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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 426 journals)
Showing 1 - 200 of 265 Journals sorted alphabetically
AAS Open Research     Open Access   (Followers: 1)
ABC Journal of Advanced Research     Open Access  
Accountability in Research: Policies and Quality Assurance     Hybrid Journal   (Followers: 22)
Acta Materialia Transilvanica     Open Access  
Acta Nova     Open Access   (Followers: 1)
Acta Scientifica Malaysia     Open Access  
Acta Scientifica Naturalis     Open Access   (Followers: 3)
Adıyaman University Journal of Science     Open Access  
Advanced Science     Open Access   (Followers: 13)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 11)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 5)
Advances in Research     Open Access  
Advances in Science and Technology     Full-text available via subscription   (Followers: 17)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 8)
Afrique Science : Revue Internationale des Sciences et Technologie     Open Access   (Followers: 2)
AFRREV STECH : An International Journal of Science and Technology     Open Access   (Followers: 4)
American Academic & Scholarly Research Journal     Open Access   (Followers: 6)
American Journal of Applied Sciences     Open Access   (Followers: 27)
American Journal of Humanities and Social Sciences     Open Access   (Followers: 17)
ANALES de la Universidad Central del Ecuador     Open Access   (Followers: 4)
Anales del Instituto de la Patagonia     Open Access  
Applied Mathematics and Nonlinear Sciences     Open Access   (Followers: 1)
Apuntes de Ciencia & Sociedad     Open Access  
Arab Journal of Basic and Applied Sciences     Open Access  
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives Internationales d'Histoire des Sciences     Partially Free   (Followers: 7)
Archives of Current Research International     Open Access  
ARO. The Scientific Journal of Koya University     Open Access  
ARPHA Conference Abstracts     Open Access   (Followers: 6)
ARPHA Proceedings     Open Access   (Followers: 5)
ArtefaCToS : Revista de estudios sobre la ciencia y la tecnología     Open Access   (Followers: 1)
Asia-Pacific Journal of Science and Technology     Open Access  
Asian Journal of Advanced Research and Reports     Open Access   (Followers: 2)
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 2)
Asian Journal of Scientific Research     Open Access   (Followers: 3)
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 7)
Australian Field Ornithology     Full-text available via subscription   (Followers: 4)
Australian Journal of Social Issues     Hybrid Journal   (Followers: 7)
AZimuth     Full-text available via subscription   (Followers: 2)
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 10)
Berkeley Scientific Journal     Full-text available via subscription  
BIBECHANA     Open Access   (Followers: 2)
BibNum     Open Access  
Bilge International Journal of Science and Technology Research     Open Access   (Followers: 1)
Bioethics Research Notes     Full-text available via subscription   (Followers: 16)
Bistua : Revista de la Facultad de Ciencias Básicas     Open Access  
BJHS Themes     Open Access   (Followers: 1)
Black Sea Journal of Engineering and Science     Open Access  
Borneo Journal of Resource Science and Technology     Open Access  
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Bulletin de la Société Royale des Sciences de Liège     Open Access  
Bulletin of the National Research Centre     Open Access  
Butlletí de la Institució Catalana d'Història Natural     Open Access  
Central European Journal of Clinical Research     Open Access  
Chain Reaction     Full-text available via subscription  
Ciencia & Natura     Open Access   (Followers: 1)
Ciencia Amazónica (Iquitos)     Open Access   (Followers: 1)
Ciencia en Desarrollo     Open Access   (Followers: 3)
Ciencia en su PC     Open Access   (Followers: 1)
Ciencia Ergo Sum     Open Access  
Ciência ET Praxis     Open Access  
Ciencia y Tecnología     Open Access  
Ciencia, Docencia y Tecnología     Open Access  
Ciencias Holguin     Open Access   (Followers: 2)
CienciaUAT     Open Access   (Followers: 1)
Citizen Science : Theory and Practice     Open Access   (Followers: 2)
Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
Communications in Applied Sciences     Open Access  
Comprehensive Therapy     Hybrid Journal   (Followers: 3)
Comunicata Scientiae     Open Access   (Followers: 1)
ConCiencia     Open Access  
Conference Papers in Science     Open Access   (Followers: 2)
Configurations     Full-text available via subscription   (Followers: 10)
COSMOS     Hybrid Journal   (Followers: 1)
Crea Ciencia Revista Científica     Open Access   (Followers: 2)
Cuadernos de Investigación UNED     Open Access  
Current Issues in Criminal Justice     Hybrid Journal   (Followers: 15)
Current Research in Geoscience     Open Access   (Followers: 8)
Dalat University Journal of Science     Open Access  
Data     Open Access   (Followers: 5)
Data Curation Profiles Directory     Open Access   (Followers: 5)
Dhaka University Journal of Science     Open Access  
Dharmakarya     Open Access  
Diálogos Interdisciplinares     Open Access  
Digithum     Open Access   (Followers: 2)
Discover Sustainability     Open Access   (Followers: 3)
Einstein (São Paulo)     Open Access  
Ekaia : EHUko Zientzia eta Teknologia aldizkaria     Open Access  
Elkawnie : Journal of Islamic Science and Technology     Open Access  
Emergent Scientist     Open Access  
Enhancing Learning in the Social Sciences     Open Access   (Followers: 9)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Entramado     Open Access  
Entre Ciencia e Ingeniería     Open Access   (Followers: 1)
Epiphany     Open Access   (Followers: 4)
Ergo     Open Access  
Estação Científica (UNIFAP)     Open Access   (Followers: 1)
Ethiopian Journal of Education and Sciences     Open Access   (Followers: 6)
Ethiopian Journal of Science and Technology     Open Access  
Ethiopian Journal of Sciences and Sustainable Development     Open Access   (Followers: 5)
European Online Journal of Natural and Social Sciences     Open Access   (Followers: 12)
European Scientific Journal     Open Access   (Followers: 10)
Evidência - Ciência e Biotecnologia - Interdisciplinar     Open Access  
Exchanges : the Warwick Research Journal     Open Access   (Followers: 2)
Experimental Results     Open Access   (Followers: 1)
Extensionismo, Innovación y Transferencia Tecnológica     Open Access   (Followers: 3)
Facets     Open Access  
Fides et Ratio : Revista de Difusión Cultural y Científica     Open Access   (Followers: 1)
Fırat University Turkish Journal of Science & Technology     Open Access  
Fontanus     Open Access  
Forensic Science Policy & Management: An International Journal     Hybrid Journal   (Followers: 378)
Frontiers for Young Minds     Open Access  
Frontiers in Climate     Open Access   (Followers: 3)
Frontiers in Science     Open Access   (Followers: 1)
Fundamental Research     Open Access  
Futures & Foresight Science     Hybrid Journal   (Followers: 4)
Gaudium Sciendi     Open Access   (Followers: 1)
Gazi University Journal of Science     Open Access  
Ghana Studies     Full-text available via subscription   (Followers: 15)
Global Journal of Pure and Applied Sciences     Full-text available via subscription  
Global Journal of Science Frontier Research     Open Access   (Followers: 2)
Globe, The     Full-text available via subscription   (Followers: 4)
HardwareX     Open Access  
Heidelberger Jahrbücher Online     Open Access  
Heliyon     Open Access  
Himalayan Journal of Science and Technology     Open Access   (Followers: 1)
History of Science and Technology     Open Access   (Followers: 1)
Hoosier Science Teacher     Open Access  
Iberoamerican Journal of Science Measurement and Communication     Open Access  
Impact     Open Access   (Followers: 2)
Indian Journal of History of Science     Hybrid Journal   (Followers: 2)
Indonesian Journal of Fundamental Sciences     Open Access  
Indonesian Journal of Science and Mathematics Education     Open Access   (Followers: 4)
Indonesian Journal of Science and Technology     Open Access  
Ingenieria y Ciencia     Open Access   (Followers: 1)
Innovare : Revista de ciencia y tecnología     Open Access  
Instruments     Open Access  
Integrated Research Advances     Open Access  
Interciencia     Open Access   (Followers: 1)
Interface Focus     Full-text available via subscription  
International Annals of Science     Open Access  
International Archives of Science and Technology     Open Access  
International Journal of Academic Research in Business, Arts & Science     Open Access   (Followers: 2)
International Journal of Advanced Multidisciplinary Research and Review     Open Access  
International Journal of Applied Science     Open Access  
International Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
International Journal of Computational and Experimental Science and Engineering (IJCESEN)     Open Access  
International Journal of Culture and Modernity     Open Access   (Followers: 3)
International Journal of Engineering, Science and Technology     Open Access  
International Journal of Innovation and Applied Studies     Open Access   (Followers: 12)
International Journal of Innovative Research and Scientific Studies     Open Access   (Followers: 6)
International Journal of Network Science     Hybrid Journal   (Followers: 3)
International Journal of Recent Contributions from Engineering, Science & IT     Open Access   (Followers: 1)
International Journal of Research in Science     Open Access   (Followers: 2)
International Journal of Science & Emerging Technologies     Open Access   (Followers: 1)
International Journal of Social Sciences and Management     Open Access   (Followers: 3)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 7)
International Letters of Social and Humanistic Sciences     Open Access   (Followers: 1)
International Review of Applied Sciences     Open Access  
InterSciencePlace     Open Access   (Followers: 1)
Investiga : TEC     Open Access  
Investigación Joven     Open Access  
Investigación Valdizana     Open Access  
Investigacion y Ciencia     Open Access   (Followers: 1)
Iranian Journal of Science and Technology, Transactions A : Science     Hybrid Journal  
iScience     Open Access   (Followers: 2)
Issues in Science & Technology     Free   (Followers: 7)
Ithaca : Viaggio nella Scienza     Open Access  
J : Multidisciplinary Scientific Journal     Open Access  
Jaunujų mokslininkų darbai     Open Access   (Followers: 1)
Journal de la Recherche Scientifique de l'Universite de Lome     Full-text available via subscription   (Followers: 2)
Journal of Chromatography & Separation Techniques     Open Access   (Followers: 12)
Journal of Advanced Research     Open Access   (Followers: 3)
Journal of Al-Qadisiyah for Pure Science     Open Access   (Followers: 1)
Journal of Alasmarya University     Open Access   (Followers: 3)
Journal of Analytical Science & Technology     Open Access   (Followers: 6)
Journal of Applied Science and Technology     Full-text available via subscription   (Followers: 1)
Journal of Applied Sciences and Environmental Management     Open Access   (Followers: 3)
Journal of Big History     Open Access   (Followers: 3)
Journal of Composites Science     Open Access   (Followers: 3)
Journal of Critical Thought and Praxis     Open Access   (Followers: 2)
Journal of Deliberative Mechanisms in Science     Open Access  
Journal of Diversity Management     Open Access   (Followers: 6)
Journal of Indian Council of Philosophical Research     Hybrid Journal  
Journal of Institute of Science and Technology     Open Access  
Journal of Integrated Science and Technology     Open Access  
Journal of Interaction Science     Open Access   (Followers: 1)
Journal of Kerbala University     Open Access   (Followers: 1)
Journal of King Saud University - Science     Open Access   (Followers: 1)
Journal of Mathematical and Fundamental Sciences     Open Access  
Journal of Natural Sciences and Mathematics Research     Open Access  
Journal of Natural Sciences Research     Open Access   (Followers: 4)
Journal of Negative and No Positive Results     Open Access  
Journal of Responsible Technology     Open Access   (Followers: 1)
Journal of Science (JSc)     Open Access  
Journal of Science and Engineering     Open Access  
Journal of Science and Technology     Open Access   (Followers: 2)
Journal of Science and Technology     Open Access   (Followers: 1)

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Journal of Composites Science
Number of Followers: 3  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2504-477X
Published by MDPI Homepage  [238 journals]
  • J. Compos. Sci., Vol. 5, Pages 225: Powder Epoxy for One-Shot Cure,
           Out-of-Autoclave Applications: Lap Shear Strength and Z-Pinning Study

    • Authors: Thomas Noble, James R. Davidson, Christophe Floreani, Ankur Bajpai, William Moses, Thomas Dooher, Alistair McIlhagger, Edward Archer, Conchúr M. Ó Brádaigh, Colin Robert
      First page: 225
      Abstract: Large composite structures manufactured out-of-autoclave require the assembly and bonding of multiple parts. A one-shot cure manufacturing method is demonstrated using powder epoxy. Lap shear plates were manufactured from powder epoxy and glass fiber-reinforced plastic with four different bonding cases were assessed: secondary bonding using standard adhesive film, secondary bonding using powder epoxy, co-curing, and co-curing plus a novel Z-pinning method. This work investigates the lap shear strength of the four cases in accordance with ISO 4587:2003. Damage mechanisms and fracture behavior were explored using digital image correlation (DIC) and scanning electron microscopy (SEM), respectively. VTFA400 adhesive had a load at break 24.8% lower than secondary bonding using powder epoxy. Co-curing increased the load at break by 7.8% compared to powder epoxy secondary bonding, with the co-cured and pinned joint resulting in a 45.4% increase. In the co-cured and co-cured plus pinned cases, DIC indicated premature failure due to resin spew. SEM indicated shear failure of resin areas and a large amount of fiber pullout in both these cases, with pinning delaying fracture phenomena resulting in increased lap joint strength. This highlights the potential of powder epoxy for the co-curing of large composite structures out-of-autoclave.
      Citation: Journal of Composites Science
      PubDate: 2021-08-24
      DOI: 10.3390/jcs5090225
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 226: Improving the Alignment of Dynamic
           Sheet-Formed Mats by Changing Nozzle Geometry and Their Reinforcement of
           Polypropylene Matrix Composites

    • Authors: Tom Sunny, Kim L. Pickering, John McDonald-Wharry
      First page: 226
      Abstract: The main objective of this study was to improve the orientation of fibres within the mats produced using dynamic sheet forming (DSF). DSF is used to make fibre mats by forcing a fibre suspension through a nozzle onto a rotating drum. In this research, the effect of nozzle geometry on the orientation of hemp fibres within DSF mats was investigated. The orientation of fibres within the mats produced was assessed using ImageJ (OrientationJ) and X-ray diffraction. It was found that, as the contraction ratio of the nozzle increased, the orientation of fibres within the fibre mats increased. It was also found that the composite tensile strength increased with increased fibre orientation.
      Citation: Journal of Composites Science
      PubDate: 2021-08-27
      DOI: 10.3390/jcs5090226
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 227: Bioactive Calcium Phosphate-Based
           Composites for Bone Regeneration

    • Authors: Marta Tavoni, Massimiliano Dapporto, Anna Tampieri, Simone Sprio
      First page: 227
      Abstract: Calcium phosphates (CaPs) are widely accepted biomaterials able to promote the regeneration of bone tissue. However, the regeneration of critical-sized bone defects has been considered challenging, and the development of bioceramics exhibiting enhanced bioactivity, bioresorbability and mechanical performance is highly demanded. In this respect, the tuning of their chemical composition, crystal size and morphology have been the matter of intense research in the last decades, including the preparation of composites. The development of effective bioceramic composite scaffolds relies on effective manufacturing techniques able to control the final multi-scale porosity of the devices, relevant to ensure osteointegration and bio-competent mechanical performance. In this context, the present work provides an overview about the reported strategies to develop and optimize bioceramics, while also highlighting future perspectives in the development of bioactive ceramic composites for bone tissue regeneration.
      Citation: Journal of Composites Science
      PubDate: 2021-08-27
      DOI: 10.3390/jcs5090227
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 228: Mechanical and Microstructural
           Response of Aluminum Composites Reinforced with Ceramic Micro-Particles

    • Authors: José A. Castillo-Robles, Alicia P. Dimas-Muñoz, José A. Rodríguez-García, Carlos A. Calles-Arriaga, Eddie N. Armendáriz-Mireles, Wilian J. Pech-Rodríguez, Enrique Rocha-Rangel
      First page: 228
      Abstract: Aluminum matrix composites have recently taken an important role in advanced applications because they have a good combination of physical and chemical properties. For this reason, in this work, aluminum composites, with additions of ceramic particles (mullite or tungsten carbide), were manufactured in order to determine the effect of those particles on the mechanical properties and microstructure of aluminum. The manufacture of the composites was carried out by means of powder metallurgy. We studied composites with additions of 0.5 and 1 vol.% of the respective ceramic. Composites were sintered at 580 and 601 °C, which corresponds to 88 and 91% of the melting point of aluminum, respectively. Observations in SEM, together with EDX analysis, confirm that mullite particles are located at intragranular and transgranular positions of the aluminum matrix, while tungsten carbide particles were found mostly at intragranular areas of the matrix. From the analysis of the studied ceramics, it was found that with the use of mullite, there are greater improvements in the hardness and elastic modulus of the manufactured composite.
      Citation: Journal of Composites Science
      PubDate: 2021-08-27
      DOI: 10.3390/jcs5090228
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 229: An Efficient Thermal Cure Profile for
           Thick Parts Made by Reactive Processing of Acrylic Thermoplastic
           Composites

    • Authors: Barbara Palmieri, Angelo Petriccione, Giuseppe De Tommaso, Michele Giordano, Alfonso Martone
      First page: 229
      Abstract: The process of curing of large thick composite parts needs attention regarding the formation of residual stresses. Similarly, novel reactive thermoplastics need investigating to produce an efficient thermal cure profile that decreases the risk of warpage and residual stress. In this work, the polymerization kinetics of the Elium resin system is investigated by differential scanning calorimetry (DSC) tests, the analysis of thermo-grams, and the parameters of Kamal and Sourour’s semi-empirical model. A numerical model based on finite elements was set up to reproduce the temperature fields during part consolidation. Several processing conditions were investigated (dwell temperature, environment, heat exchange) in order to predict the thermal gradient within the part. The optimal cure profile was identified as a function of process parameters with the aim of minimizing the thermal gradient within the composite element. The analysis revealed that, for the reactive thermoplastic Elium, the consolidation in facilities with high thermal exchange may increase the risk of residual stresses within the parts, erasing the advantage of short cure cycles.
      Citation: Journal of Composites Science
      PubDate: 2021-08-29
      DOI: 10.3390/jcs5090229
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 230: Cumulative Shear Damage Mechanism to
           Short Fiber Type C/SiC

    • Authors: Yuta Tobata, Shinsuke Takeuchi, Ken Goto
      First page: 230
      Abstract: A cumulative damage mechanism for short fiber type C/SiC during shear loading–unloading testing was examined and quantified using Iosipescu specimens parallel in the in-plane and through-thickness plane, and by using modified fracture and damage mechanics theory referring to measured damage characteristics (crack length, number and angle). A nonlinear stress–strain relation was found for both specimens. Decrease in the apparent modulus was confirmed with increased peak stress, although permanent strain increased. Inelastic strain of the decomposed tensile direction derived from shear stress was greater than that of the compressive one. Cracks propagated perpendicularly to the tensile direction, intruding on the boundary of the transverse fibers and connecting to other cracks. The theoretical damage mechanics model succeeded to predict the stress–strain relation, proposing that the shear mechanical properties are predictable by measuring the damage characteristics.
      Citation: Journal of Composites Science
      PubDate: 2021-08-30
      DOI: 10.3390/jcs5090230
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 231: Green Ceramic Machining: Determination
           of the Recommended Feed Rate for Y-TZP Milling

    • Authors: Anthonin Demarbaix, Marylou Mulliez, Edouard Rivière-Lorphèvre, Laurent Spitaels, Charles Duterte, Nicolas Preux, Fabrice Petit, François Ducobu
      First page: 231
      Abstract: Manufacturing of advanced ceramic parts exhibiting complex geometries is laborious and expensive. Traditionally, the machining is carried out on a so-called ‘green ceramic’: a compact composed of ceramic powder held with the help of a binder. This difficulty is due not only to the composition of the material, but also to the lack of methods that determine optimal machining parameters. The goal of this paper is to apply the method based on ductile material behavior to determine a feed rate working range to ensure a machining quality. Indeed, a previous study demonstrated the limits of this method in determining cutting speed. In this case, two material removal mechanisms are observed: a mechanism dominated by pulling of the material and a proper machining mechanism. This demonstrates that the specific cutting energy is a reliable indicator for machining quality assessment. In the studied case, the recommended machining parameters to ensure quality machining of Y-TZP green ceramic with a 3 mm diameter cylindrical tool are: a cutting speed of 250 m/min, a feed per tooth of 0.037 mm/tooth, an axial depth of cut of 0.7 mm, and a radial depth of cut of 3 mm.
      Citation: Journal of Composites Science
      PubDate: 2021-09-01
      DOI: 10.3390/jcs5090231
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 232: Modified Polylactic Acid with Improved
           Impact Resistance in the Presence of a Thermoplastic Elastomer and the
           Influence of Fused Filament Fabrication on Its Physical Properties

    • Authors: Samir Kasmi, Julien Cayuela, Bertrand De Backer, Eric Labbé, Sébastien Alix
      First page: 232
      Abstract: The standard polylactic acid (PLA), as a biodegradable thermoplastic polymer, is commonly used in various industrial sectors, food, and medical fields. Unfortunately, it is characterized by a low elongation at break and low impact energy. In this study, a thermoplastic copolyester elastomer (TPCE) was added at different weight ratios to improve the impact resistance of PLA. DSC analysis revealed that the two polymers were immiscible. A good balance of impact resistance and rigidity was reached using the formulation that was composed of 80% PLA and 20% TPCE, with an elongation at break of 155% compared to 4% for neat PLA. This new formulation was selected to be tested in a fused filament fabrication process. The influence of the nozzle and bed temperatures as printing parameters on the mechanical and thermal properties was explored. Better impact resistance was observed with the increase in the two thermal printing parameters. The crystallinity degree was not influenced by the variation in the nozzle temperature. However, it was increased at higher bed temperatures. Tomographic observations showed an anisotropic distribution of the porosity, where it was mostly present between the adjacent printed filaments and it was reduced with the increase in the nozzle and bed temperatures.
      Citation: Journal of Composites Science
      PubDate: 2021-09-02
      DOI: 10.3390/jcs5090232
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 233: Polyaniline/Nanomaterial Composites
           for the Removal of Heavy Metals by Adsorption: A Review

    • Authors: Hind Hajjaoui, Amal Soufi, Wafaa Boumya, Mohamed Abdennouri, Noureddine Barka
      First page: 233
      Abstract: Heavy metals represent one of the most important kinds of pollutants, causing serious threats to the ecological balance. Thus, their removal from aqueous solution is a major environmental concern worldwide. The process of adsorption—being very simple, economical, and effective—is widely applied for the decontamination of wastewaters from heavy metals. In this process, the adsorbent is the key factor affecting the performance; for this reason, significant efforts have been made to develop highly efficient and selective adsorbents with outstanding properties. This paper presents a detailed overview of the research on different methods of synthesis of nanocomposite materials based on the polymer polyaniline combined with nanomaterials, along with the influence of the synthesis method on their size, morphology, and properties. In addition, the study evaluates the adsorption efficiency of various developed nanocomposites for the adsorption of heavy metals from aqueous solution. From an economical and environmental point of view, the regeneration studies of the nanocomposites are also reported.
      Citation: Journal of Composites Science
      PubDate: 2021-09-03
      DOI: 10.3390/jcs5090233
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 234: Mechanical Properties of a
           Biocomposite Based on Carbon Nanotube and Graphene Nanoplatelet Reinforced
           Polymers: Analytical and Numerical Study

    • Authors: Marwane Rouway, Mourad Nachtane, Mostapha Tarfaoui, Nabil Chakhchaoui, Lhaj El Hachemi Omari, Fouzia Fraija, Omar Cherkaoui
      First page: 234
      Abstract: Biocomposites based on thermoplastic polymers and natural fibers have recently been used in wind turbine blades, to replace non-biodegradable materials. In addition, carbon nanofillers, including carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), are being implemented to enhance the mechanical performance of composites. In this work, the Mori–Tanaka approach is used for homogenization of a polymer matrix reinforced by CNT and GNP nanofillers for the first homogenization, and then, for the second homogenization, the effective matrix was used with alfa and E-glass isotropic fibers. The objective is to study the influence of the volume fraction Vf and aspect ratio AR of nanofillers on the elastic properties of the composite. The inclusions are considered in a unidirectional and random orientation by using a computational method by Digimat-MF/FE and analytical approaches by Chamis, Hashin–Rosen and Halpin–Tsai. The results show that CNT- and GNP-reinforced nanocomposites have better performance than those without reinforcement. Additionally, by increasing the volume fraction and aspect ratio of nanofillers, Young’s modulus E increases and Poisson’s ratio ν decreases. In addition, the composites have enhanced mechanical characteristics in the longitudinal orientation for CNT- reinforced polymer and in the transversal orientation for GNP-reinforced polymer.
      Citation: Journal of Composites Science
      PubDate: 2021-09-03
      DOI: 10.3390/jcs5090234
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 235: Milling of an Aluminium Matrix
           Composite Using MCD-Tipped Tools with Adjusted Corner and Minor Cutting
           Edge Geometries

    • Authors: Benjamin Clauß, Andreas Schubert
      First page: 235
      Abstract: Aluminium matrix composites (AMCs) represent suitable materials for lightweight design applications. The abrasive ceramic reinforcements typically require diamond cutting materials to prevent excessive tool wear. In milling with diamond cutting materials the influence of cutting parameters was already examined to a significant extent. Investigations concerning the effect of modified tool geometries are limited and the potentials with regard to the geometrical and physical surface properties are unclear. Accordingly, experimental investigations in milling of a 10 vol.% SiC particle-reinforced aluminium wrought alloy EN AW-2017 T4 were addressed. The effect of modified corner and minor cutting edge geometries were investigated based on mono crystalline diamond (MCD)-tipped tools to benefit stable process conditions. The results indicated achievable areal roughness values in the range around 0.2μm. Especially the application of the lowest cutting edge angle and a trailing minor cutting edge led to strong fluctuations of the surface parameters. The lowest valley void volumes were achieved with an arched minor cutting edge. Generally, finish machining led to stronger compressive residual stresses compared to the state prior to machining. The strongest increase was achieved using a corner radius combined with a straight minor cutting edge. It is concluded that reduced effective radii generating the surface enable an acceptable surface structure and strong compressive residual stresses and should be addressed in further investigations.
      Citation: Journal of Composites Science
      PubDate: 2021-09-04
      DOI: 10.3390/jcs5090235
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 236: Hemoglobin–Polyaniline Composite and
           Electrochemical Field Effective Transistors

    • Authors: Mai Ichikawa, Hiromasa Goto
      First page: 236
      Abstract: A composite of hemoglobin/polyaniline was prepared. The chemical structure of this obtained composite was confirmed using infrared absorption spectroscopy measurement. The luminol reaction of the composite manifested chemical emissions from the composite. Furthermore, electrochemical transistors using the composite were created. The hemoglobin/polyaniline-based electrochemical transistor could switch to external current flow via an electrochemical reaction. The color of the transistor surface changed from green to red upon applying electrochemical potential.
      Citation: Journal of Composites Science
      PubDate: 2021-09-04
      DOI: 10.3390/jcs5090236
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 237: Mechanical and Durability
           Characteristics Assessment of Geopolymer Composite (GPC) at Varying Silica
           Fume Content

    • Authors: Ankur Gupta, Nakul Gupta, Kuldeep Kumar Saxena
      First page: 237
      Abstract: The present study aimed at assessing mechanical and durability characteristics of ground granulated blast furnace slag (GGBS)-based geopolymer composites at 5%, 10%, 15%, 20%, 25%, and 30% replacement proportion of silica fume at 12 molarity of NaOH. Mechanical properties were assessed using compression and tension tests, whereas durability characteristics were evaluated using ultrasonic pulse velocity test (UPV), acid test, and rapid chloride permeability test (RCPT), and water absorption (WA) test. Additionally, reduction in mass and strength were also determined due to the acid action on the developed composites. A correlation of compressive strength was also established with the splitting tensile strength, UPV, RCPT, and WA. The presence of silica fume and high NaOH concentration in GPC tends to improve the mechanical strength up toa certain level. UPV values obtained were falling in the range of medium to good category. Chloride ion penetration and water absorption values were reduced by around 23% and 26%, respectively, at 10% silica fume replacement. Mass loss and strength loss were reduced as the % of silica fume increased. A good correlation of compressive strength was obtained with tensile strength, UPV, and RCPT with a coefficient of determination of 0.9681, 0.9665, and 0.9208, respectively. Poor correlation was obtained between compressive strength and water absorption.
      Citation: Journal of Composites Science
      PubDate: 2021-09-05
      DOI: 10.3390/jcs5090237
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 238: Error Analysis of Non-Destructive
           Ultrasonic Testing of Glass Fiber-Reinforced Polymer Hull Plates

    • Authors: Zhiqiang Han, Jaewon Jang, Sang-Gyu Lee, Dongkun Lee, Daekyun Oh
      First page: 238
      Abstract: Glass fiber-reinforced polymer (GFRP) ship structures are generally fabricated by hand lay-up; thus, the environmental factors and worker proficiency influence the fabrication process and presence of error in the non-destructive evaluation results. In this study, the ultrasonic testing of GFRP hull plate prototypes was conducted to investigate the statistical significance of the influences of the design parameters, e.g., the glass fiber weight fraction (Gc) and thickness variations, on the measurement error. The GFRP hull plate prototypes were fitted with E-glass fiber chopped strand mats (40 wt % content) with different thicknesses (7.72 mm, 14.63 mm, and 18.24 mm). The errors in the thickness measurements were investigated by conducting pulse-echo ultrasonic A-scan. The thickness variation resulted in increased error. Furthermore, hull plate burn-off tests were conducted to investigate the fabrication qualities. Defects such as voids did not have a significant influence on the results. The statistical analysis of the measurement errors confirmed that the thickness variations resulted in a strong ultrasonic interference between the hull plates, although the hull plates had similar specific gravity values. Therefore, the ultrasonic interference of the layer group interface should be considered to decrease the GFRP hull NDE errors with respect to an increase in the thickness and Gc.
      Citation: Journal of Composites Science
      PubDate: 2021-09-07
      DOI: 10.3390/jcs5090238
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 239: Energy Direction in Ultrasonic
           Impregnation of Continuous Fiber-Reinforced Thermoplastics

    • Authors: Julian Popp, Michael Wolf, Tobias Mattner, Dietmar Drummer
      First page: 239
      Abstract: As a new and innovative processing method for fabrication for fiber-reinforced thermoplastic composites (CFRTs), the feasibility of ultrasonic welding technology was proven in several studies. This method offers potential for the direct manufacturing of CFRT–metal structures via embedded pin structures. Despite the previous studies, a deeper understanding of the process of energy input and whether fibers work as energy directors and consequently can, in combination with chosen processing parameters, influence the consolidation quality of the CFRTs, is still unknown. Consequently, the aim of this work is to establish a deeper process understanding of the ultrasonic direct impregnation of fiber-reinforced thermoplastics with an emphasis on the fiber’s function as energy directors. Based on the generated insights, a better assessment of the feasibility of direct, hybrid part manufacturing is possible. The produced samples were primarily evaluated by optical and mechanical test methods. It is demonstrated that with higher welding time and amplitude, a better consolidation quality can be achieved and that independent of the process parameters chosen in this study, no significant fiber breakage occurs. This is interpreted as a sign of a gentle impregnation process. Furthermore, based on the examination of single roving and 5-layer set-ups, it is shown that the glass fibers function as energy directors and can influence the transformation of sonic energy into thermal energy. In comparison to industrially available CFRT material, the mechanical properties are weaker, but materials and processes offer potential for significant improvement. Based on these findings, proposals for a direct impregnation and joining process are made.
      Citation: Journal of Composites Science
      PubDate: 2021-09-07
      DOI: 10.3390/jcs5090239
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 240: Hydrogen Bonds in Blends of
           Poly(N-isopropylacrylamide), Poly(N-ethylacrylamide) Homopolymers, and
           Carboxymethyl Cellulose

    • Authors: Alberto García-Peñas, Weijun Liang, Saud Hashmi, Gaurav Sharma, Mohammad Reza Saeb, Florian J. Stadler
      First page: 240
      Abstract: Recently, it was reported that the physical crosslinking exhibited by some biopolymers could provide multiple benefits to biomedical applications. In particular, grafting thermoresponsive polymers onto biopolymers may enhance the degradability or offer other features, as thermothickening behavior. Thus, different interactions will affect the different hydrogen bonds and interactions from the physical crosslinking of carboxymethyl cellulose, the lower critical solution temperatures (LCSTs), and the presence of the ions. This work focuses on the study of blends composed of poly(N-isopropylacrylamide), poly(N-ethylacrylamide), and carboxymethyl cellulose in water and water/methanol. The molecular features, thermoresponsive behavior, and gelation phenomena are deeply studied. The ratio defined by both homopolymers will alter the final properties and the gelation of the final structures, showing that the presence of the hydrophilic groups modifies the number and contributions of the diverse hydrogen bonds.
      Citation: Journal of Composites Science
      PubDate: 2021-09-08
      DOI: 10.3390/jcs5090240
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 241: Editorial for the Special Issue on
           Advanced Fiber-Reinforced Polymer Composites

    • Authors: Mohammad H. Malakooti, Christopher C. Bowland
      First page: 241
      Abstract: Fiber-reinforced polymer (FRP) composites are ubiquitous structural materials owing to their high specific strength, impact resistance, and scalable manufacturing [...]
      Citation: Journal of Composites Science
      PubDate: 2021-09-10
      DOI: 10.3390/jcs5090241
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 242: Toughening and Healing of CFRPs by
           Electrospun Diels–Alder Based Polymers Modified with Carbon Nano-Fillers
           

    • Authors: Athanasios Kotrotsos, Constantinos Rouvalis, Anna Geitona, Vassilis Kostopoulos
      First page: 242
      Abstract: In the present investigation, thermo-reversible bonds formed between maleimide and furan groups (Diels–Alder (DA)-based bis-maleimides (BMI)) have been generated to enable high-performance unidirectional (UD) carbon fiber-reinforced plastics (CFRPs) with self-healing (SH) functionality. The incorporation of the SH agent (SHA) was performed locally, only in areas of interest, with the solution electrospinning process (SEP) technique. More precisely, reference and modified CFRPs with (a) pure SHA, (b) SHA modified with multi-walled carbon nano-tubes (MWCNTs) and (c) SHA modified with graphene nano-platelets (GNPs) were fabricated and further tested under Mode I loading conditions. According to experimental results, it was shown that the interlaminar fracture toughness properties of modified CFRPs were considerably enhanced, with GNP-modified ones to exhibit the best toughening performance. After the first fracture and the activation of the healing process, C-scan inspections revealed, macroscopically, a healing efficiency (H.E.) of 100%; however, after repeating the tests, a low recovery of mechanical properties was achieved. Finally, optical microscopy (OM) examinations not only showed that the epoxy matrix at the interface was partly infiltrated by the DA resin, but it also revealed the presence of pulled-out fibers at the fractured surfaces, indicating extended fiber bridging between crack flanks due to the presence of the SHA.
      Citation: Journal of Composites Science
      PubDate: 2021-09-10
      DOI: 10.3390/jcs5090242
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 243: Tackling the Circular Economy
           Challenges—Composites Recycling: Used Tyres, Wind Turbine Blades, and
           Solar Panels

    • Authors: Kinga Korniejenko, Barbara Kozub, Agnieszka Bąk, Ponnambalam Balamurugan, Marimuthu Uthayakumar, Gabriel Furtos
      First page: 243
      Abstract: Transformation of waste into resources is an important part of the circular economy. Nowadays, the recovery of materials in the most effective way is crucial for sustainable development. Composite materials offer great opportunities for product development and high performance in use, but their position in a circular economy system remains challenging, especially in terms of material recovery. Currently, the methods applied for recycling composites are not always effective. The aim of the article is to analyse the most important methods of material recovery from multilateral composites. The manuscript presents three case studies related to the recycling of products manufactured from composites: used tyres, wind turbine blades, and solar panels. It shows the advantages and disadvantages of currently applied methods for multilateral composite utilisation and presents further trends in composite recycling. The results show that increasing volumes of end-of-life composites have led to increased attention from government, industry, and academia.
      Citation: Journal of Composites Science
      PubDate: 2021-09-11
      DOI: 10.3390/jcs5090243
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 244: New Perspectives on Zirconia
           Composites as Biomaterials

    • Authors: Giuseppe Magnani, Paride Fabbri, Enrico Leoni, Elena Salernitano, Francesca Mazzanti
      First page: 244
      Abstract: Zirconia–alumina composites couple the high toughness of zirconia with the peculiar properties of alumina, i.e., hardness, wear, and chemical resistance, so they are considered promising materials for orthopedic and dental implants. The design of high performance zirconia composites needs to consider different aspects, such as the type and amount of stabilizer and the sintering process, that affect the mechanics of toughening and, hence, the mechanical properties. In this study, several stabilizers (Y2O3, CuO, Ta2O5, and CeO2) were tested together with different sintering processes to analyze the in situ toughening mechanism induced by the tetragonal–monoclinic (t–m) transformation of zirconia. One of the most important outcomes is the comprehension of the opposite effect played by the grain size and the tetragonality of the zirconia lattice on mechanical properties, such as fracture toughness and bending strength. These results allow for the design of materials with customized properties and open new perspectives for the development of high-performance zirconia composites for orthopedic implants with high hydrothermal resistance. Moreover, a near-net shape forming process based on the additive manufacturing technology of digital light processing (DLP) was also studied to produce ceramic dental implants with a new type of resin–ceramic powder mixture. This represents a new frontier in the development of zirconia composites thanks to the possibility to obtain a customized component with limited consumption of material and reduced machining costs.
      Citation: Journal of Composites Science
      PubDate: 2021-09-11
      DOI: 10.3390/jcs5090244
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 245: Conducting-Polymer Nanocomposites as
           Synergistic Supports That Accelerate Electro-Catalysis: PEDOT/Nano
           Co3O4/rGO as a Photo Catalyst of Oxygen Production from Water

    • Authors: Mohammed Alsultan, Anwer M. Ameen, Amar Al-keisy, Gerhard F. Swiegers
      First page: 245
      Abstract: This work describes how conducting polymer nanocomposites can be employed as synergistic supports that significantly accelerate the rate of electro-catalysis. The nanocomposite PEDOT/nano-Co3O4/rGO is discussed as an example in this respect, which is specific for photo electro-catalytic oxygen (O2) generation from water using light (PEDOT = poly (3,4-ethylenedioxythiophene); rGO = reduced graphene oxide). We show that the conducting polymer PEDOT and the conductive additive rGO may be used to notably amplify the rate of O2-generation from water by the nano catalyst, Co3O4. A composite film containing the precise molar ratio 7.18 (C; PEDOT):1 (Co):5.18 (C; rGO) exhibited high photocatalytic activity (pH 12) for the oxygen evolution reaction (OER) at 0.80 V (vs. Ag/AgCl), with a current density of 1000 ± 50 μA/cm2 (including a photocurrent of 500 μA/cm2), achieved after >42 h of operation under illumination with a light of intensity 0.25 sun. By comparison, the best industrial catalyst, Pt, yielded a much lower 150 μA/cm2 under the same conditions. Oxygen gas was the sole product of the reaction.
      Citation: Journal of Composites Science
      PubDate: 2021-09-12
      DOI: 10.3390/jcs5090245
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 246: Laser Butt Welding of Thin Ti6Al4V
           Sheets: Effects of Welding Parameters

    • Authors: Peter Omoniyi, Rasheedat Mahamood, Nana Arthur, Sisa Pityana, Samuel Skhosane, Yasuhiro Okamoto, Togo Shinonaga, Martin Maina, Tien-Chien Jen, Esther Akinlabi
      First page: 246
      Abstract: Titanium and its alloys, particularly Ti6Al4V, which is widely utilized in the marine and aerospace industries, have played a vital role in different manufacturing industries. An efficient and cost-effective way of joining this metal is by laser welding. The effect of laser power and welding speed on the tensile, microhardness, and microstructure of Ti6Al4V alloy is investigated in this paper. Results show that the microhardness is highest at the fusion zone and reduces towards the base metal. The microstructure at the fusion zone shows a transformed needle-like lamellar α phase, with a martensitic α’ phase observed within the heat affected zone. Results of tensile tests show an improved tensile strength compared to the base metal.
      Citation: Journal of Composites Science
      PubDate: 2021-09-14
      DOI: 10.3390/jcs5090246
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 247: Synthesis and Fabrication of
           Co1−xNixCr2O4 Chromate Nanoparticles and the Effect of Ni Concentration
           on Their Bandgap, Structure, and Optical Properties

    • Authors: Muhammad Saeed, Malika Rani, Kiran Batool, Hafiza Batool, Aisha Younus, Sikander Azam, Arshad Mehmood, Bakhtiarul Haq, Thamraa Alshahrani, Ghafar Ali, Muhammad Maqbool
      First page: 247
      Abstract: In the present work, cobalt-chromite-based pigment Co1-xNixCr2O4 chromate powder and nanoparticles with various transition metal concentrations (x = 0.2, 0.4, 0.6, and 0.8) were manufactured by applying aqueous synthesis approaches and sol–gel synthesis routes. XRD analysis of the powder shows that all samples formulated by the sol–gel method were crystalline with a spinel structure. Chromites show green color with a higher nickel concentration, while Co-substituent shows blackish pigments. Samples were annealed at distinct temperatures ranging from 600 °C to 750 °C. The nanoparticles obtained were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy (RS), photoluminescence (PL), and energy-dispersive X-ray spectroscopy (EDS). The particle size of the parent compound (CoCr2O4) ranges from 100 nm to 500 nm, as measured by SEM. The tendency of particles to form aggregates with increasing annealing temperature was observed. These compounds may be successfully used as an effective doped nickel-cobalt ceramic pigment.
      Citation: Journal of Composites Science
      PubDate: 2021-09-14
      DOI: 10.3390/jcs5090247
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 248: Experimental Investigation of In-Plane
           Shear Behaviour of Thermoplastic Fibre-Reinforced Composites under
           Thermoforming Process Conditions

    • Authors: Nikita Pyatov, Harish Karthi Natarajan, Tim A. Osswald
      First page: 248
      Abstract: In order to meet environmental regulations and achieve resource efficiency in the series production of vehicles, recyclable polymer composites with a high strength-to-weight ratio are increasingly being used as materials for structural components. Particularly with thermoplastic fibre-reinforced polymers or organo-sheets, the advantage lies in the tailored mechanical properties of the final component by adapting the orientation of fibres based on the direction of loads. These components produced by thermoforming organo-sheets also offer a cost benefit and short cycle times. During the thermoforming process, the shear behaviour of the organo-sheet is the most dominant and determines the mechanical properties and quality of the resulting component. However, the current standard for characterising the shear behaviour of organo-sheets does not consider the strain and cooling rates inherent in the thermoforming process. This research investigates the influence of thermoforming process parameters on the shear behaviour of organo-sheets with a new methodology combining DSC and DMA experiments. During the thermoforming process, the transition of the matrix material from a molten state to a solid state is dictated by the crystallisation kinetics and their dependence on heating and cooling rates. Thus, non-isothermal DSC scans, which correspond to a temperature cycle in a thermoforming process, are used in the DSC experiments to establish the relationship between the recrystallisation temperature of the organo-sheet material and the cooling/heating rates in the thermoforming process. In order to achieve thermoforming-process-relevant cooling rates, fast scanning calorimetry (Flash DSC) is used in addition to conventional DSC measurements. DMA experiments carried out with 45° fibre orientation show that the recrystallisation temperature consequently influences the shear storage modulus of the organo-sheet. The results from DSC measurements show a shift of recrystallisation temperatures to lower temperatures as the cooling rate increases. The combined analysis of results from the DSC and DMA experiments supports the findings and shows the influence of the process temperature, cooling rate and strain rate on the recrystallisation temperature and, in turn, the shear behaviour of organo-sheets. Thus, a recommendation for establishing a new standard for characterising the shear behaviour of organo-sheets is made.
      Citation: Journal of Composites Science
      PubDate: 2021-09-15
      DOI: 10.3390/jcs5090248
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 249: Electrical and Mechanical Properties
           of Sugarcane Bagasse Pyrolyzed Biochar Reinforced Polyvinyl Alcohol
           Biocomposite Films

    • Authors: Kawsar Ahmed, Mahbub Hasan, Julfikar Haider
      First page: 249
      Abstract: Biochar obtained from the oxygen-deficient thermochemical processing of organic wastes is considered to be an effective reinforcing agent in biocomposite development. In the present research, biocomposite film was prepared using sugarcane bagasse pyrolyzed biochar and polyvinyl alcohol (PVA), and its electrical and mechanical properties were assessed. The biocomposite films were produced by varying content (5 wt.%, 8 wt.% and 12 wt.%) of the biochar produced at 400 °C, 600 °C, 800 °C and 1000 °C and characterized using X-Ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy. The experimental findings revealed that biochar produced at a higher pyrolyzing temperature could significantly improve the electrical conductance of the biocomposite film. A maximum electrical conductance of 7.67 × 10−2 S was observed for 12 wt.% addition of biochar produced at 1000 °C. A trend of improvement in the electrical properties of the biocomposite films suggested a threshold wt.% of the biochar needed to make a continuous conductive network across the biocomposite film. Rapid degradation of tensile strength was observed with an increasing level of biochar dosage. The lowest tensile strength 3.12 MPa was recorded for the film with 12 wt.% of biochar produced at 800 °C. Pyrolyzing temperature showed a minor impact on the mechanical strength of the biocomposite. The prepared biocomposites could be used as an electrically conductive layer in electronic devices.
      Citation: Journal of Composites Science
      PubDate: 2021-09-18
      DOI: 10.3390/jcs5090249
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 250: Benzoxazine Copolymers with Mono- and
           Difunctional Epoxy Active Diluents with Enhanced Tackiness and Reduced
           Viscosity

    • Authors: Natalia V. Bornosuz, Roman F. Korotkov, Vyacheslav V. Shutov, Igor S. Sirotin, Irina Yu. Gorbunova
      First page: 250
      Abstract: The influence of epoxy active diluents, 1,4-butanediol diglycidyl ether (BD) and furfuryl glycidyl ether (FUR), in the mixtures with benzoxazine monomer based on bisphenol A, formaldehyde and m-toluidine (BA-mt), on the properties of a matrix was disclosed in this work. Resins were modified to achieve good tackiness at room temperature and reduced viscosity. The influence of mono- and difunctional modifiers on the process of curing was studied by way of differential scanning calorimetry and oscillatory rheology. The addition of BD and FUR shifted the curing peak to higher temperatures and significantly reduced viscosity. Preferable tackiness at ambient temperature was achieved with 10 phr of epoxy components in mixtures. However, cured blends with difunctional epoxy BD had an advantage over monofunctional FUR in enhanced tensile strength with remaining glass transition temperature at the level of neat benzoxazine (217 °C).
      Citation: Journal of Composites Science
      PubDate: 2021-09-18
      DOI: 10.3390/jcs5090250
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 251: Progressive Fatigue Failure Analysis
           of a Filament Wound Ring Specimen with a Hole

    • Authors: Eivind Hugaas, Nils Petter Vedvik, Andreas T. Echtermeyer
      First page: 251
      Abstract: A progressive FEA mechanical fatigue degradation model for composites was developed and implemented using a UMAT user material subroutine in Abaqus. Numerical results were compared to experimental strain field data from high frequency digital image correlation (DIC) of split disk fatigue testing of pressure vessel cut outs with holes. The model correctly predicted the onset and evolution of damage in the matrix as well as the onset of fiber failure. The model uses progressive failure analysis based on the maximum strain failure criterion, the cycle jump method, and Miner’s sum damage accumulation rule. A parameter study on matrix properties was needed to capture the scatter in strain fields observed experimentally by DIC. S-N curve for the matrix material had to be lowered by 0% to 60% to capture the experimental scatter. The onset of local fiber failure had to be described by local S-N curves measured by DIC having 2.5 times greater strain than that of S-N curves found from standard coupon testing.
      Citation: Journal of Composites Science
      PubDate: 2021-09-18
      DOI: 10.3390/jcs5090251
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 252: Magnetic Behavior of an Iron
           Gluconate/Polyaniline Composite

    • Authors: Yusuke Koshikawa, Hiromasa Goto
      First page: 252
      Abstract: Oxidative polymerization conducted the synthesis of polyaniline in the presence of iron gluconate in the water. Iron gluconate is present in the resulting polyaniline (PANI). The PANI composite exhibited multiple signals in electron spin resonance, including half-field resonance of multiple spin states, the center-field resonance of polarons as radical cations in conducting polymer, and a signal from a defect in the main chain. Infrared (IR) absorption spectroscopy measurements confirmed the chemical structure of the PANI composite. The composite exhibits the mixed magnetism of PANI as a conducting polymer and Fe ions in the composite according to superconducting interference device (SQUID) measurements. Combining organic-conjugated polymers and inorganic materials can result in a unique magnetism.
      Citation: Journal of Composites Science
      PubDate: 2021-09-19
      DOI: 10.3390/jcs5090252
      Issue No: Vol. 5, No. 9 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 195: Edge Race-Tracking during Film-Sealed
           Compression Resin Transfer Molding

    • Authors: Mario Vollmer, Swen Zaremba, Pierre Mertiny, Klaus Drechsler
      First page: 195
      Abstract: Edge race-tracking is a frequently reported issue during resin transfer molding. It is caused by highly permeable channels and areas between the preform edge and cavity, which can significantly change the preform impregnation pattern. To date, information is scarce on the effect of edge race-tracking in compression resin transfer molding (CRTM). To close this gap, laboratory equipment was developed to study the CRTM preform impregnation via flow visualization experiments. The preform was thereby encapsulated in thin thermoplastic films sealing its impregnation. Film-sealed compression resin transfer molding (FS-CRTM) experiments of preforms with a small geometrical aspect ratio showed fast filling of the injection gap and a subsequent through-thickness preform impregnation. Creating an edge race-tracking channel, an additional lateral in-plane flow from the channel towards the preform center was observed, initiating soon after the injection started and caused by the spatial connection between the injection gap and the race-tracking channel. To diminish edge race-tracking, a passive flow control strategy was implemented via a split design of the upper tool to spatially isolate the injection gap from the channel and to pre-compact the preform edge. A delayed and reduced lateral race-tracking flow was observed, showing that the passive flow control strategy increases the process robustness of FS-CRTM regarding edge race-tracking effects.
      Citation: Journal of Composites Science
      PubDate: 2021-07-21
      DOI: 10.3390/jcs5080195
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 196: Effect of Filler Morphology on the
           Electrical and Thermal Conductivity of PP/Carbon-Based Nanocomposites

    • Authors: Marta Zaccone, Alberto Frache, Luigi Torre, Ilaria Armentano, Marco Monti
      First page: 196
      Abstract: In this paper, we studied the effect of different carbon-based nanostructures on the electrical and mechanical properties of polypropylene (PP) nanocomposites. Multi-walled carbon nanotubes (MWCNT), expanded graphite (EG), and two different carbon black nanoparticles (CB) have been dispersed at several weight contents in the polymer matrix through a melt extrusion process. The produced nanocomposites have been used to obtain samples for the characterization by injection molding. The dispersion of the nanoparticles in the matrix has been evaluated by scanning electron microscopy (SEM) analysis. The electrical characterization has been performed both in DC and in AC configuration. The mechanical properties have been evaluated with both tensile test and impact strength (Izod). The thermal conductivity has been also evaluated. As a result, MWCNTs are the nanoadditive with the lowest electrical percolation threshold. This allows MWCNT nanocomposite to drastically change the electrical behavior without a significant embrittlement observed with the other nanoadditives. However, CB with the lowest surface area allows the highest conductivity, even though at a high particle content. EG has a limited effect on electrical properties, but it is the only one with a significant effect on thermal conductivity.
      Citation: Journal of Composites Science
      PubDate: 2021-07-23
      DOI: 10.3390/jcs5080196
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 197: Stress-Function Variational Method for
           Accurate Free-Edge Interfacial Stress Analysis of Adhesively Bonded
           Single-Lap Joints and Single-Sided Joints

    • Authors: Xiang-Fa Wu, Youhao Zhao, Oksana Zholobko
      First page: 197
      Abstract: Large free-edge interfacial stresses induced in adhesively bonded joints (ABJs) are responsible for the commonly observed debonding failure in ABJs. Accurate and efficient stress analysis of ABJs is important to the design, structural optimization, and failure analysis of ABJs subjected to external mechanical and thermomechanical loads. This paper generalizes the high-efficiency semi-analytic stress-function variational methods developed by the authors for accurate free-edge interfacial stress analysis of ABJs of various geometrical configurations. Numerical results of the interfacial stresses of two types of common ABJs, i.e., adhesively bonded single-lap joints and adhesively single-sided joints, are demonstrated by using the present method, which are further validated by finite element analysis (FEA). The numerical procedure formulated in this study indicates that the present semi-analytic stress-function variational method can be conveniently implemented for accurate free-edge interfacial stress analysis of various type of ABJs by only slightly modifying the force boundary conditions. This method is applicable for strength analysis and structural design of broad ABJs made of multi-materials such as composite laminates, smart materials, etc.
      Citation: Journal of Composites Science
      PubDate: 2021-07-23
      DOI: 10.3390/jcs5080197
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 198: Correlation of Process Conditions,
           Porosity Levels and Crystallinity in Atmospherically Plasma Sprayed
           Yb2Si2O7 Environmental Barrier Coatings

    • Authors: Robert Vaßen, Emine Bakan, Doris Sebold, Yoo Jung Sohn
      First page: 198
      Abstract: Environmental barrier coatings are necessary to protect fibre reinforced ceramics from high recession rates in fast and hot water vapor-containing gases as they typically are found in the hot gas sections of gas turbines. A standard material to protect SiC/SiC composites is atmospherically plasma sprayed (APS) Yb2Si2O7. For this material, it is difficult to obtain at reasonable substrate temperatures both low porosity and high crystallinity levels during APS. In this paper results of coatings prepared by a so-called high velocity APS process and also more conventional processes are presented. All coatings have been prepared by a single layer deposition method which avoids inter passage porosity bands. Furthermore, the samples were heat-treated in air at 1300 °C for 100 h and the influence of the topcoat density on the growth of the silica scale on the used silicon bond coat was studied.
      Citation: Journal of Composites Science
      PubDate: 2021-07-28
      DOI: 10.3390/jcs5080198
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 199: Dynamic Gelation of Conductive Polymer
           Nanocomposites Consisting of Poly(3-hexylthiophene) and ZnO Nanowires

    • Authors: Franceska A. Santos, Dana J. Christensen, Ryan Y. Cox, Spencer A. Schultz, Raymond H. Fernando, Shanju Zhang
      First page: 199
      Abstract: The sol–gel transition of conductive nanocomposites consisting of poly(3-hexylthiophene) (P3HT) and ZnO nanowires in o-dichlorobenzene (o-DCB) has been investigated rheologically. The physical gelation of P3HT in o-DCB spontaneously occurs upon adding the small amount of ZnO nanowires. The rheological properties of the P3HT/ZnO nanocomposite gels have been systematically studied by varying factors such as polymer concentration, nanowire loading, and temperature. The nanocomposite gel exhibits shear-thinning in the low shear rate range and shear-thickening in the high shear rate range. The elastic storage modulus of the nanocomposite gel gradually increases with gelation time and is consistently independent of frequency at all investigated ranges. The isothermal gelation kinetics has been analyzed by monitoring the storage modulus with gelation time, and the data are well fitted with a first-order rate law. The structural analysis data reveal that the polymer forms the crystalline layer coated on ZnO nanowires. A fringed micelle model is proposed to explain the possible gelation mechanism.
      Citation: Journal of Composites Science
      PubDate: 2021-07-30
      DOI: 10.3390/jcs5080199
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 200: Cellulose Nanocomposites of Cellulose
           Nanofibers and Molecular Coils

    • Authors: Doug Henderson, Xin Zhang, Yimin Mao, Liangbing Hu, Robert M. Briber, Howard Wang
      First page: 200
      Abstract: All-cellulose nanocomposites have been produced from cellulose nanofiber (CNF) suspensions and molecular coil solutions. Morphology and small-angle neutron scattering studies show the exfoliation and dispersion of CNFs in aqueous suspensions. Cellulose solutions in mixtures of ionic liquid and organic solvents were homogeneously mixed with CNF suspensions and subsequently dried to yield cellulose composites comprising CNF and amorphous cellulose over the entire composition range. Tensile tests show that stiffness and strength quantities of cellulose nanocomposites are the highest value at ca. 20% amorphous cellulose, while their fracture strain and toughness are the lowest. The inclusion of amorphous cellulose in cellulose nanocomposites alters their water uptake capacity, as measured in the ratio of the absorbed water to the cellulose mass, reducing from 37 for the neat CNF to less than 1 for a composite containing 35% or more amorphous cellulose. This study offers new insights into the design and production of all-cellulose nanocomposites.
      Citation: Journal of Composites Science
      PubDate: 2021-07-30
      DOI: 10.3390/jcs5080200
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 201: Influence of Rigid Brazilian Natural
           Fiber Arrangements in Polymer Composites: Energy Absorption and Ballistic
           Efficiency

    • Authors: Fabio C. Garcia Filho, Fernanda S. Luz, Michelle S. Oliveira, Wendell B. A. Bezerra, Josiane D. V. Barbosa, Sergio N. Monteiro
      First page: 201
      Abstract: Since the mid-2000s, several studies were carried out regarding the development of ballistic resistant materials based on polymeric matrix composites reinforced with natural lignocellulosic fibers (NLFs). The results reported so far are promising and are often comparable to commonly used materials such as KevlarTM, especially when used as an intermediate layer in a multilayer armor system (MAS). However, the most suitable configuration for these polymer composites reinforced with NLFs when subjected to high strain rates still lacks investigation. This work aimed to evaluate four possible arrangements for epoxy matrix composite reinforced with a stiff Brazilian NLF, piassava fiber, regarding energy absorption, and ballistic efficiency. Performance was evaluated against the ballistic impact of high-energy 7.62 mm ammunition. Obtained results were statistically validated by means of analysis of variance (ANOVA) and Tukey’s honest test. Furthermore, the micromechanics associated with the failure of these composites were determined. Energy absorption of the same magnitude as KevlarTM and indentation depth below the limit predicted by NIJ standard were obtained for all conditions.
      Citation: Journal of Composites Science
      PubDate: 2021-08-01
      DOI: 10.3390/jcs5080201
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 202: Green Nanocomposites for Energy
           Storage

    • Authors: Ayesha Kausar
      First page: 202
      Abstract: The green nanocomposites have elite features of sustainable polymers and eco-friendly nanofillers. The green or eco-friendly nanomaterials are low cost, lightweight, eco-friendly, and highly competent for the range of energy applications. This article initially expresses the notions of eco-polymers, eco-nanofillers, and green nanocomposites. Afterward, the energy-related applications of the green nanocomposites have been specified. The green nanocomposites have been used in various energy devices such as solar cells, batteries, light-emitting diodes, etc. The main focus of this artifact is the energy storage application of green nanocomposites. The capacitors have been recognized as corporate devices for energy storage, particularly electrical energy. In this regard, high-performance supercapacitors have been proposed based on sustainable nanocomposites. Consequently, this article presents various approaches providing key knowledge for the design and development of multi-functional energy storage materials. In addition, the future prospects of the green nanocomposites towards energy storage have been discussed.
      Citation: Journal of Composites Science
      PubDate: 2021-08-02
      DOI: 10.3390/jcs5080202
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 203: Engineering Properties of Hybrid Fibre
           Reinforced Ternary Blend Geopolymer Concrete

    • Authors: V. Sathish Kumar, N. Ganesan, P. V. Indira
      First page: 203
      Abstract: The primary aim of this research is to find an alternative for Portland cement using inorganic geopolymers. This study investigated the effect of steel and polypropylene fibres hybridisation on ternary blend geopolymer concrete (TGPC) engineering properties using fly ash, ground granulated blast furnace slag (GGBS) and metakaolin as the source materials. The properties like compressive strength, splitting tensile strength, flexural strength and modulus of elasticity of ternary blend geopolymer concrete. The standard tests were conducted on TGPC with steel fibres, polypropylene fibres and a combination of steel and polypropylene fibres in hybrid form. A total number of 45 specimens were tested and compared to determine each property. The grade of concrete considered was M55. The variables studied were the volume fraction of fibres, viz. steel fibres (0%, 0.5% and 1%) and polypropylene fibres (0%, 0.1%, 0.15%, 0.2% and 0.25%). The experimental results reveal that the addition of fibres in a hybrid form enhances the mechanical properties of TGPC. The increase in the compressive strength was nominal, and a significant improvement was observed in splitting tensile strength, flexural strength, and modulus of elasticity. Also, an attempt to obtain the relation between the different engineering properties was made with different volume fractions of fibre.
      Citation: Journal of Composites Science
      PubDate: 2021-08-03
      DOI: 10.3390/jcs5080203
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 204: Electromagnetic Shielding
           Effectiveness of Glass Fiber/Epoxy Laminated Composites with Multi-Scale
           Reinforcements

    • Authors: Nilufar Yesmin, Vijaya Chalivendra
      First page: 204
      Abstract: In this study, an experimental investigation has been performed to understand the electromagnetic interference-shielding effectiveness (EMI-SE) of glass fiber/epoxy laminated composites embedded with carbon nanotubes (CNTs) and Fe3O4 nanoparticles, reinforced with micro carbon fibers along the thickness direction. Micro carbon fibers were reinforced along the thickness direction between the laminates using an electro-flocking process and a vacuum infusion process used to fabricate the composites. The EMI-SE of the composites was measured in the X-band frequency range (8–12 GHz). The effect of carbon fibers of three different lengths (80 µm, 150 µm, and 350 µm) with two different fiber densities (1000 and 2000 fibers/mm2) and two different amounts of Fe3O4 nanoparticles (0.5 and 1 wt.%) on total SE, absorption, and reflection was investigated. Due to the synergetic effect of Fe3O4 nanoparticles, CNTs, and carbon fibers, the final EMI shielding of the composites was mainly dominated by the absorption process. The absorption was more pronounced in the composites of longer carbon fibers with improved electrical conductivity. The presence of Fe3O4 nanoparticles also enhanced total SE values with improved magnetic permeability. The composite with micro carbon fibers of 350 µm length and 2000 fibers/mm2 density with 1 wt.% of Fe3O4 nanoparticles showed the maximum value of total SE.
      Citation: Journal of Composites Science
      PubDate: 2021-08-03
      DOI: 10.3390/jcs5080204
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 205: A Study on the Effect of Construction
           and Demolition Waste (CDW) Plastic Fractions on the Moisture and
           Resistance to Indentation of Wood-Polymer Composites (WPC)

    • Authors: Ville Lahtela, Timo Kärki
      First page: 205
      Abstract: This paper investigated the moisture and strength properties of wood-polymer composites (WPC), which were made using three different recycled polymers using wood flour as filler. The recycled polymers were acrylonitrile butadiene styrene (ABS), polypropylene (PP), and polyethylene (PE), which were collected from among the construction and demolition waste (CDW) at a local waste management center. The commercial additives, such as a coupling agent and lubricant, were also included in the materials. Composite materials were manufactured with an agglomeration and an extrusion process. Water absorption and thickness swelling properties of composites, based on the recycled ABS and PE, were restricted compared to the recycled PP. The strength properties of WPC were determined with two methods, a traditional Brinell hardness and resistance to indentation. Using an ABS polymer as a matrix in the composite, the moisture and strength properties were improved. The recycled PP polymer caused these properties to be lowered, especially in the case of moisture properties. This study has shown that the method used can affect the measured value of certain properties. In addition, the sorting of recycled polymer fractions is desirable for the appearance of improved properties.
      Citation: Journal of Composites Science
      PubDate: 2021-08-03
      DOI: 10.3390/jcs5080205
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 206: Oxide Bioceramic Composites in
           Orthopedics and Dentistry

    • Authors: Corrado Piconi, Simone Sprio
      First page: 206
      Abstract: Ceramic composites based on alumina and zirconia have found a wide field of application in the present century in orthopedic joint replacements, and their use in dentistry is spreading. The development of this class of bioceramic composites was started in the 1980s, but the first clinical applications of the total hip replacement joint were introduced in the market only in the early 2000s. Since then, several composite systems were introduced in joint replacements. These materials are classified as Zirconia-Toughened Alumina if alumina is the main component or as Alumina-Toughened Zirconia when zirconia is the main component. In addition, some of them may contain a third phase based on strontium exa-aluminate. The flexibility in device design due to the excellent mechanical behavior of this class of bioceramics results in a number of innovative devices for joint replacements in the hip, the knee, and the shoulder, as well in dental implants. This paper gives an overview of the different materials available and on orthopedic and dental devices made out of oxide bioceramic composites today on the market or under development.
      Citation: Journal of Composites Science
      PubDate: 2021-08-03
      DOI: 10.3390/jcs5080206
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 207: Fabrication of h-MoO3 Nanorods and the
           Properties of the MoO3/WEP Composite Coatings Research

    • Authors: Ying Zhou, Cuihuan Song, Zhixiang Chen, Qixin Zhou
      First page: 207
      Abstract: In this study, we prepared a novel coating composed of hexagonal molybdenum oxide (h-MoO3) nanofiller and waterborne epoxy resin (WEP) to provide corrosion protection. We optimized the h-MoO3 nanorod synthesis methodology first by changing different parameters (pH, temperature, etc.). Furthermore, the as-prepared h-MoO3 rods were characterized using a scanning electron microscope (SEM) and X-ray diffraction (XRD). Finally, the electrochemical impedance spectroscopy (EIS) test results verified that the anticorrosive performance of the composite coatings was improved by incorporation of low content of MoO3 nanofiller (0.5 wt.%) compared to pure WEP sample. This developed composite will provide a new insight for the design and fabrication of one-dimensional (1D) nanomaterial (e.g., nanorod) reinforced epoxy coating and other polymeric coating processes.
      Citation: Journal of Composites Science
      PubDate: 2021-08-04
      DOI: 10.3390/jcs5080207
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 208: Chloramphenicol Loaded Sponges Based
           on PVA/Nanocellulose Nanocomposites for Topical Wound Delivery

    • Authors: Evangelia D. Balla, Nikolaos D. Bikiaris, Stavroula G. Nanaki, Chrysanthi Papoulia, Konstantinos Chrissafis, Panagiotis A. Klonos, Apostolos Kyritsis, Margaritis Kostoglou, Alexandra Zamboulis, George Z. Papageorgiou
      First page: 208
      Abstract: In the present study, polymer sponges based on poly(vinyl alcohol) (PVA) were prepared for the topical wound administration of chloramphenicol (CHL), an antibiotic widely used to treat bacterial infections. Nanocellulose fibrils (CNF) were homogenously dispersed in PVA sponges in three different ratios (2.5, 5, and 10 wt %) to improve the mechanical properties of neat PVA sponges. Infrared spectroscopy showed hydrogen bond formation between CNF and PVA, while scanning electron microscopy photos verified the successful dispersion of CNF to PVA sponges. The addition of CNF successfully enhanced the mechanical properties of PVA sponges, exhibiting higher compressive strength as the content of CNF increased. The PVA sponge containing 10 wt % CNF, due to its higher compression strength, was further studied as a matrix for CHL delivery in 10, 20, and 30 wt % concentration of the drug. X-ray diffraction showed that CHL was encapsulated in an amorphous state in the 10 and 20 wt % samples, while some crystallinity was observed in the 30 wt % ratio. In vitro dissolution studies showed enhanced CHL solubility after its incorporation in PVA/10 wt % CNF sponges. Release profiles showed a controlled release lasting three days for the sample containing 10 wt % CHL and 1.5 days for the other two samples. According to modelling, the release is driven by a pseudo-Fickian diffusion.
      Citation: Journal of Composites Science
      PubDate: 2021-08-06
      DOI: 10.3390/jcs5080208
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 209: Influences on Textile and Mechanical
           Properties of Recycled Carbon Fiber Nonwovens Produced by Carding

    • Authors: Frank Manis, Georg Stegschuster, Jakob Wölling, Stefan Schlichter
      First page: 209
      Abstract: Nonwovens made of recycled carbon fibers (rCF) and thermoplastic (TP) fibers have excellent economic and ecological potential. In contrast to new fibers, recycled carbon fibers are significantly cheaper, and the CO2 footprint is mostly compensated by energy savings in the first product life cycle. The next step for this promising material is its industrial serial use. Therefore, we analyzed the process chain from fiber to composite material. Initially, the rCF length at different positions during the carding process was measured. Thereafter, we evaluated the influence of the TP fibers on the processing, fiber shortening, and mechanical properties. Finally, several nonwovens with different TP fibers and fiber volume contents between 15 vol% and 30 vol% were produced, consolidated by hot-pressing, and tested by four-point bending to determine the mechanical values. The fiber length reduction ranged from 20.6% to 28.4%. TP fibers cushioned the rCF against mechanical stress but held rCF fragments back due to their crimp. The resulting bending strength varied from 301 to 405 MPa, and the stiffness ranged from 16.3 to 30.1 GPa. Design recommendations for reduced fiber shortening are derived as well as material mixtures that offer better homogeneity and higher mechanical properties.
      Citation: Journal of Composites Science
      PubDate: 2021-08-06
      DOI: 10.3390/jcs5080209
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 210: Computational Investigation of
           Crack-Induced Hot-Spot Generation in Energetic Composites

    • Authors: Xingzi Yang, Liqiang Lin, Justin Wilkerson, Xiaowei Zeng
      First page: 210
      Abstract: The sensitivity of polymer-bonded explosives (PBXs) can be tuned through adjusting binder material and its volume fraction, crystal composition and morphology. To obtain a better understanding of the correlation between grain-level failure and hot-spot generation in this kind of energetic composites as they undergo mechanical and thermal processes subsequent to impact, a recently developed interfacial cohesive zone model (ICZM) was used to study the dynamic response of polymer-bonded explosives. The ICZM can capture the contributions of deformation and fracture of the binder phase as well as interfacial debonding and subsequent friction on hot-spot generation. In this study, a two-dimensional (2D) finite element (FE) computational model of energetic composite was developed. The proposed computational model has been applied to simulate hot-spot generation in polymer-bonded explosives with different grain volume fraction under dynamic loading. Our simulation showed that the increase of binder phase material volume fraction will decrease the local heat generation, resulting in a lower temperature in the specimen.
      Citation: Journal of Composites Science
      PubDate: 2021-08-10
      DOI: 10.3390/jcs5080210
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 211: A Generalized and Modular Framework
           for Digital Generation of Composite Microstructures

    • Authors: Ahmet Cecen, Berkay Yucel, Surya R. Kalidindi
      First page: 211
      Abstract: This paper presents a generalized framework for the digital generation of composite microstructures using filter-based approaches that can devise and utilize a wide variety of cost functions reflecting the desired targets on geometrical and statistical measures. The use of filter-based approaches leads to remarkable computational advantages compared to the conventional approaches used currently for microstructure generation. The framework provides a highly modular and flexible approach to generate stochastic ensembles of microstructures meeting user-defined microstructural characteristics. The proposed framework is illustrated in this paper through selected case studies.
      Citation: Journal of Composites Science
      PubDate: 2021-08-11
      DOI: 10.3390/jcs5080211
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 212: Thermal/Electrical Properties and
           Texture of Carbon Black PC Polymer Composites near the Electrical
           Percolation Threshold

    • Authors: Valentina Brunella, Beatrice Gaia Rossatto, Chiara Mastropasqua, Federico Cesano, Domenica Scarano
      First page: 212
      Abstract: Polycarbonate (PC), a thermoplastic polymer with excellent properties, is used in many advanced technological applications. When PC is blended with other polymers or additives, new properties, such as electrical properties, can be available. In this study, carbon black (CB) was melt-compounded with PC to produce polymer compounds with compositions (10–16 wt.% of CB), which are close to or above the electrical percolation threshold (13.5–14 wt.% of CB). Effects due to nanofiller dispersion/aggregation in the polymer matrix, together with phase composition, glass transition temperature, morphology and textural properties, were studied by using thermal analysis methods (thermogravimetry and differential scanning calorimetry) and scanning electron microscopy. The DC electrical properties of these materials were also investigated by means of electrical conductivity measurements and correlated with the “structure” of the CB, to better explain the behaviour of the composites close to the percolation threshold.
      Citation: Journal of Composites Science
      PubDate: 2021-08-11
      DOI: 10.3390/jcs5080212
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 213: The Direct Cause of Amplified
           Wettability: Roughness or Surface Chemistry'

    • Authors: Emmanuel E. Ubuo, Inimfon A. Udoetok, Andrew T. Tyowua, Ifiok O. Ekwere, Hamza S. Al-Shehri
      First page: 213
      Abstract: Higher contact angles or amplified wettability observed on surfaces of rough solid materials are typically expressed as a function of a physical dimension (roughness factor). Herein, we present a simple experimental approach that demonstrates that roughness may only magnify the inherent surface chemistry that seems to have direct influence on surface wettability. We investigate gradual change in surface chemistry (hydrophobisation) of rough and smooth glass surfaces, from a very low concentration (10−7 M) of dichlorodimethylsilane, DCDMS through various intermediate hydrophilic/hydrophobic states to when the surfaces are maximally hydrophobised with DCDMS at 0.1 M. The wettability of the modified glasses was studied by water contact angle measurements using drop shape analysis system (DSA). The data obtained indicate a deviation from Wenzel model, with the functionalized rough glass surfaces showing higher reactivity towards DCDMS when compared to the smooth glass surfaces, indicating that the two surfaces are not chemically identical. Our study reveals that just like transforming a solid material to powder, a well-divided glass (rough) surface may not only exhibit a greater surface area than the smooth counterpart as rightly predicted by the Wenzel model, but seems to be bloated with functional groups (–OH or –CH3) that can amplify surface interaction when such functional species dominate the solid surface.
      Citation: Journal of Composites Science
      PubDate: 2021-08-12
      DOI: 10.3390/jcs5080213
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 214: Fibre-Reinforced Geopolymer Composites
           Micro-Nanochemistry by SEM-EDS Simulations

    • Authors: Daniele Moro, Gianfranco Ulian, Giovanni Valdrè
      First page: 214
      Abstract: The focus of the present study is on fibre-reinforced geopolymer composites, whose optimization and application necessarily need a detailed chemical characterization at the micro-nanoscale. In this regard, many geopolymer composites presenting micro and nanometric architectures pose a challenge for scanning electron microscopy with energy dispersive X-ray microanalysis (SEM-EDS) quantification, because of several potential sources of errors. For this reason, the present work reports a SEM-EDS Monte Carlo approach to carefully investigate the complex physical phenomena related to the cited quantification errors. The model used for this theoretical analysis is a simplified fibre-reinforced geopolymer with basalt-derived glass fibres immersed in a potassium-poly(sialate-siloxo) matrix. The simulated SEM-EDS spectra showed a strong influence on the measured X-ray intensity of (i) the sample nano-to-micro architecture, (ii) the electron beam probing energy and (iii) the electron probe-sample-EDS detector relative position. The results showed that, compared to a bulk material, the X-ray intensity for a nano-micrometric sized specimen may give rise to potential underestimation and/or overestimation of the elemental composition of the sample. The proposed Monte Carlo approach indicated the optimal instrumental setup depending on the sample and on the specific SEM-EDS equipment here considered.
      Citation: Journal of Composites Science
      PubDate: 2021-08-12
      DOI: 10.3390/jcs5080214
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 215: Mechanical and Tribological Attributes
           of Al-CNT-Sn Composites Prepared by Press and Sintering

    • Authors: Vilas Dhore, Walmik Rathod, Kashinath Patil
      First page: 215
      Abstract: Carbon nanotubes (CNTs) have shown tremendous progress during the past two decades due to their extraordinary properties. With CNTs added as an alloying element, various engineering materials exhibit better mechanical properties. Multi-walled carbon nanotubes (MWCNT) were synthesized in-house by chemical vapor deposition process. Carbon nanotube-reinforced aluminum composites were prepared by cold pressing (or compaction) and sintering using different fractions (0.5, 1.0, 1.5, and 2.0 weight percent) of MWCNTs. The Al-CNT composites consists of tin (Sn) at 1.0 wt. % in each composition. Tin promotes the sintering of aluminum matrix composite. The effect of CNT on the density, hardness, and wear behavior of the composites were studied. Wear tests were performed to determine friction and wear under dry, wet, and hot conditions under varying loads from 5 N to 20 N. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques were used for the characterization. This investigation shows that increased CNT content significantly improves the hardness and wear resistance of the composites. The friction and wear were found to increase with operating temperature. A significant reduction in coefficient of friction and wear rate was observed with the application of oil during the wear test.
      Citation: Journal of Composites Science
      PubDate: 2021-08-12
      DOI: 10.3390/jcs5080215
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 216: Microwave Synthesis of MnO2-Lignin
           Composite Electrodes for Supercapacitors

    • Authors: Siddhi Mehta, Swarn Jha, Dali Huang, Kailash Arole, Hong Liang
      First page: 216
      Abstract: The demand for energy storage devices made from biodegradable materials has increased significantly due to sustainability. Currently, such devices possess vital issues, such as high manufacturing costs and toxicity, low reliability, as well as poor electrochemical performance. In this research, microwave synthesis was conducted to fabricate a low-cost, high-performing, plant-based electroactive material. MnO2 microparticles fabricated via microwave irradiation were deposited on two plant-based materials as substrates made of Al/lignin and Al/AC/lignin. The quasi-solid-state supercapacitors were assembled using a polymeric gel electrolyte of PVA/H3PO4. Scanning electron microscopy was performed to examine the polydispersity, morphology, and porosity of the micro-MnO2 deposited materials. FTIR and UV-vis spectroscopy were performed to study the composition and verify deposition of micro-MnO2 on the lignin-based matrixes. Cyclic voltammetry (CV) was employed to study the polarization resistance of the system. The cyclic charge-discharge (CCD) and electrochemical impedance spectroscopy (EIS) were performed to observe cyclic performance and interfacial resistances. Electrochemical tests showed that after 700 cycles of charge-discharge, both the supercapacitors exhibited high capacitance retention above 90%. Compared to the existing technology, this method enables consistent material structurization with tunable properties due to the controlled heating time and exposure to radiation with minimal waste. This work provides an alternative approach to synthesize low-cost and scalable green composite electrodes for flexible supercapacitors.
      Citation: Journal of Composites Science
      PubDate: 2021-08-13
      DOI: 10.3390/jcs5080216
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 217: New Advances and Future Possibilities
           in Forming Technology of Hybrid Metal–Polymer Composites Used in
           Aerospace Applications

    • Authors: Tomasz Trzepieciński, Sherwan Mohammed Najm, Manel Sbayti, Hedi Belhadjsalah, Marcin Szpunar, Hirpa G. Lemu
      First page: 217
      Abstract: Fibre metal laminates, hybrid composite materials built up from interlaced layers of thin metals and fibre reinforced adhesives, are future-proof materials used in the production of passenger aircraft, yachts, sailplanes, racing cars, and sports equipment. The most commercially available fibre–metal laminates are carbon reinforced aluminium laminates, aramid reinforced aluminium laminates, and glass reinforced aluminium laminates. This review emphasises the developing technologies for forming hybrid metal–polymer composites (HMPC). New advances and future possibilities in the forming technology for this group of materials is discussed. A brief classification of the currently available types of FMLs and details of their methods of fabrication are also presented. Particular emphasis was placed on the methods of shaping FMLs using plastic working techniques, i.e., incremental sheet forming, shot peening forming, press brake bending, electro-magnetic forming, hydroforming, and stamping. Current progress and the future directions of research on HMPCs are summarised and presented.
      Citation: Journal of Composites Science
      PubDate: 2021-08-13
      DOI: 10.3390/jcs5080217
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 218: New Frontiers of Composites
           Applications in Heritage Buildings: Repair of Exposed Masonry of St.
           Nicola Church in Pisa

    • Authors: Pietro Croce
      First page: 218
      Abstract: The upgrading and repair of masonry structures, which constitute a great part of built heritage, involve intricate aspects, in fact, the choice of the most suitable intervention technique is strongly dependent on its compatibility with superior preservation requirements. At present, beside more traditional approaches, many composite-based techniques are available, but, there are cases, such as exposed masonry, which are much more complicated to treat, since, to safeguard the original aspect, any intervention on the surface is precluded. In this paper, an innovative repair technique is discussed. The proposed method, highly adaptable and suitable for general application, is based on the insertion of a composite fabric into the mortar joints of the exposed masonry, partly relying on the indent repair technique traditionally used for the repair of masonry structures. Due to the peculiarities of the approach, the feasibility and efficiency of the solution cannot be demonstrated through application in the testing laboratory or on reduced samples, it was, therefore, necessary to identify a relevant case study for a field testing. After careful evaluation, duly considering the risks from the esthetic point of view, the proposed solution was implemented to repair the exposed masonry of the main façade and of the rear façade of the medieval San Nicola Church in Pisa, which is an outstanding example of the Pisan-Romanesque style. Thanks to a careful definition of the operational phases and to skilled workmanship, the solution was easily implemented in the year 2005, fully safeguarding the aesthetics of the façades, so demonstrating its feasibility. However, this successful outcome was only a first proof of the validity of the experiment, which also needed, for complete validation, the assessment of its efficiency over time. Only recently, after more than 15 years, it has been possible to ascertain that the intervention is still effective, because the crack patterns are stabilized and no reopening of the crack has occurred in the meantime, so achieving full confirmation.
      Citation: Journal of Composites Science
      PubDate: 2021-08-13
      DOI: 10.3390/jcs5080218
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 219: Green Synthesis of Gold, Silver, and
           Iron Nanoparticles for the Degradation of Organic Pollutants in Wastewater
           

    • Authors: Brajesh Kumar
      First page: 219
      Abstract: The green synthesis of nanoscale materials is of special interest to researchers all over the world. We describe a simple, robust, inexpensive, and environmentally friendly approach to the synthesis of gold, silver, and iron nanoparticles using a variety of biomolecules/phytochemicals as potential reducers and stabilizers. The green approach to the controlled synthesis of nanoparticles with different morphologies is based on the use of plant extracts. Green synthesized nanoparticles can be used as catalysts, photocatalysts, adsorbents, or alternative agents for the elimination of various organic dyes. The kinetic enhancement of nanoparticles for the degradation/removal of dyes could provide significant and valuable insights for the application of biochemically functionalized nanoparticles in engineering. In this review, current plant-mediated strategies for preparing nanoparticles of gold, silver, and iron are briefly described, and morphologically dependent nanoparticles for the degradation of organic pollutants in wastewater are highlighted. Overall, the approach presented in the article supports environmental protection and is a promising alternative to other synthesis techniques.
      Citation: Journal of Composites Science
      PubDate: 2021-08-16
      DOI: 10.3390/jcs5080219
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 220: Simplified Approach for Parameter
           Selection and Analysis of Carbon and Glass Fiber Reinforced Composite
           Beams

    • Authors: Reza Moazed, Mohammad Amir Khozeimeh, Reza Fotouhi
      First page: 220
      Abstract: In this study, a simplified approach that can be used for the selection of the design parameters of carbon and glass fiber reinforced composite beams is presented. Important design parameters including fiber angle orientation, laminate thickness, materials of construction, cross-sectional shape, and mass are considered. To allow for the integrated selection of these parameters, structural indices and efficiency metrics are developed and plotted in design charts. As the design parameters depend on mode of loading, normalized structural metrics are defined for axial, bending, torsional, and combined bending-torsional loading conditions. The design charts provide designers with an accurate and efficient approach for the determination of stiffness parameters and mass of laminated composite beams. Using the design charts, designers can readily determine optimum fiber direction, number of layers in a laminate, cross-sectional shape, and materials that will provide the desired mass and stiffness. The laminated composite beams were also analyzed through a detailed finite element analysis study. Three-dimensional solid elements were used for the finite element modelling of the beams. To confirm design accuracy, numerical results were compared with close-form solutions and results obtained from the design charts. To show the effectiveness of the design charts, the simplified method was utilized for increasing the bending and torsional stiffness of a laminated composite robotic arm. The results show that the proposed approach can be used to accurately and efficiently analyze composite beams that fall within the boundaries of the design charts.
      Citation: Journal of Composites Science
      PubDate: 2021-08-18
      DOI: 10.3390/jcs5080220
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 221: Determination of Fatigue Damage
           Initiation in Short Fiber-Reinforced Thermoplastic through Acoustic
           Emission Analysis

    • Authors: Janna Krummenacker, Joachim Hausmann
      First page: 221
      Abstract: This study investigates the damage initiation in short glass fiber-reinforced polyamide 6.6 under fatigue loading using acoustic emission analysis. An optimized specimen geometry was developed to meet the specific requirements of this testing method, at the same time allowing further micromechanical studies. Specimens were preloaded with tensile–tensile fatigue loading, varying the maximum stress and the number of load cycles. Subsequently, the acoustic emission signals in residual strength tests were compared to those of undamaged specimens. The idea behind this approach is that only the damage that has not already occurred under fatigue load can be recorded in the residual strength tests. Using the analysis of acoustic energy, a stress threshold for damage initiation was identified. Furthermore, with tension–tension fatigue tests, the SN curve of the material was determined to estimate the lifetime for the identified stress threshold. The presented approach allows us to estimate a so-called endurance limit of short glass fiber-reinforced polyamide 6.6.
      Citation: Journal of Composites Science
      PubDate: 2021-08-19
      DOI: 10.3390/jcs5080221
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 222: Qualitative Investigation of Damage
           Initiation at Meso-Scale in Spheroidized C45EC Steels by Using Crystal
           Plasticity-Based Numerical Simulations

    • Authors: Muhammad Umar, Faisal Qayyum, Muhammad Umer Farooq, Sergey Guk, Ulrich Prahl
      First page: 222
      Abstract: This research uses EBSD data of two thermo-mechanically processed medium carbon (C45EC) steel samples to simulate micromechanical deformation and damage behavior. Two samples with 83% and 97% spheroidization degrees are subjected to virtual monotonic quasi-static tensile loading. The ferrite phase is assigned already reported elastic and plastic parameters, while the cementite particles are assigned elastic properties. A phenomenological constitutive material model with critical plastic strain-based ductile damage criterion is implemented in the DAMASK framework for the ferrite matrix. At the global level, the calibrated material model response matches well with experimental results, with up to ~97% accuracy. The simulation results provide essential insight into damage initiation and propagation based on the stress and strain localization due to cementite particle size, distribution, and ferrite grain orientations. In general, it is observed that the ferrite–cementite interface is prone to damage initiation at earlier stages triggered by the cementite particle clustering. Furthermore, it is observed that the crystallographic orientation strongly affects the stress and stress localization and consequently nucleating initial damage.
      Citation: Journal of Composites Science
      PubDate: 2021-08-20
      DOI: 10.3390/jcs5080222
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 223: The Versatility of HVOF Burner Rig
           Testing for Ceramic Matrix Composite Evaluation

    • Authors: Gregory N. Morscher, Ragav P. Panakarajupally, Leland Hoffman
      First page: 223
      Abstract: Effective testing of ceramic matrix composites (CMCs) and CMC/coating systems for high temperature, high stress, high velocity and/or severe oxidation/corrosion environments is a critical need in materials/coatings evaluation for extreme environments of hot section parts in jet engine and hypersonic applications. Most current technology can evaluate two or three of the extreme conditions for a given application; however, incorporating as many of the extreme thermo-mechanical-environmental factors is highly advantageous to understand combinatorial effects. A high velocity oxygen fuel (HVOF) burner rig offers an excellent platform to evaluate many of these extreme conditions. In this work, the following three different thermo-mechanical-environmental test conditions using an HVOF rig on SiC-based CMCs are highlighted: (1) fatigue at temperature for >Mach 1 velocity and high temperature compared to typical stagnant air test environment, (2) high temperature hard particle erosion at temperature for ≤Mach 1 conditions and (3) ~Mach 5 near-hypersonic velocity conditions at very high temperature exposure.
      Citation: Journal of Composites Science
      PubDate: 2021-08-20
      DOI: 10.3390/jcs5080223
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 224: Development, Testing and
           Characterization of Al NanoTiCp Composites through Powder Metallurgy
           Techniques

    • Authors: Gaurav Bajpai, Anuradha Tiwari, Rajesh Purohit, Vijay Panchore, Rashmi Dwivedi, Kosaraju Satyanarayana
      First page: 224
      Abstract: In the present scenario, weight diminution and strength enrichment are the main requirements for escalating the application of a nano composite material in different sectors. Several industrial sectors, such as automobile, defense and aerospace, are making various components of nano composites with the help of powder metallurgy processing. In this study, Al nanoTiCp composites (2, 4 and 6 wt %) were contrived through modified powder metallurgy (PM) techniques with the help of Cold Isostatic Compaction process (CIP). The mechanical properties such as density, porosity, micro-hardness, compressive strength and indirect tensile strength were increasing with the reinforcement of nanoTiCp particles up to 4 wt % in Al metal matrix composites. Nevertheless, clustering of nanoTiCp particles were found at 6 wt %, which is also observed in SEM images.
      Citation: Journal of Composites Science
      PubDate: 2021-08-22
      DOI: 10.3390/jcs5080224
      Issue No: Vol. 5, No. 8 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 187: Micromechanical Modeling Tensile and
           Fatigue Behavior of Fiber-Reinforced Ceramic-Matrix Composites Considering
           Matrix Fragmentation and Closure

    • Authors: Longbiao Li
      First page: 187
      Abstract: In this paper, micromechanical constitutive models are developed to predict the tensile and fatigue behavior of fiber-reinforced ceramic-matrix composites (CMCs) considering matrix fragmentation and closure. Damage models of matrix fragmentation, interface debonding, and fiber’s failure are considered in the micromechanical analysis of tensile response, and the matrix fragmentation closure, interface debonding and repeated sliding are considered in the hysteresis response. Relationships between the matrix fragmentation and closure, tensile and fatigue response, and interface debonding and fiber’s failure are established. Experimental matrix fragmentation density, tensile curves, and fatigue hysteresis loops of mini, unidirectional, cross-ply, and 2D plain-woven SiC/SiC composites are predicted using the developed constitutive models. Matrix fragmentation density changes with increasing or decreasing applied stress, which affects the nonlinear strain of SiC/SiC composite under tensile loading, and the interface debonding and sliding range of SiC/SiC composite under fatigue loading.
      Citation: Journal of Composites Science
      PubDate: 2021-07-16
      DOI: 10.3390/jcs5070187
      Issue No: Vol. 5, No. 7 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 188: Organic Solvent Free Process to
           Fabricate High Performance Silicon/Graphite Composite Anode

    • Authors: Chen Fang, Haiqing Xiao, Tianyue Zheng, Hua Bai, Gao Liu
      First page: 188
      Abstract: Cycling stability is a key challenge for application of silicon (Si)-based composite anodes as the severe volume fluctuation of Si readily leads to fast capacity fading. The binder is a crucial component of the composite electrodes. Although only occupying a small amount of the total composite mass, the binder has major impact on the long-term electrochemical performance of Si-based anodes. In recent years, water-based binders including styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) have attracted wide research interest as eco-friendly and low-cost alternatives for the conventional poly(vinylidene difluoride) (PVDF) binder in Si anodes. In this study, Si-based composite anodes are fabricated by simple solid mixing of the active materials with subsequent addition of SBR and CMC binders. This approach bypasses the use of toxic and expansive organic solvents. The factors of binder, silicon, and graphite materials have been systematically investigated. It is found that the retained capacities of the anodes are more than 440 mAh/g after 400 cycles. These results indicate that organic solvent free process is a facile strategy for producing high performance silicon/graphite composite anodes.
      Citation: Journal of Composites Science
      PubDate: 2021-07-17
      DOI: 10.3390/jcs5070188
      Issue No: Vol. 5, No. 7 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 189: Effect of Twist Drill Geometry and
           Drilling Parameters on Hole Quality in Single-Shot Drilling of
           CFRP/Al7075-T6 Composite Stack

    • Authors: Muhammad Hafiz Hassan, Jamaluddin Abdullah, Gérald Franz, Chim Yi Shen, Reza Mahmoodian
      First page: 189
      Abstract: Drilling two different materials in a layer, or stack-up, is being practiced widely in the aerospace industry to minimize critical dimension mismatch and error in the subsequent assembly process, but the compatibility of the drill to compensate the widely differing properties of composite is still a major challenge to the industry. In this paper, the effect of customized twist drill geometry and drilling parameters are being investigated based on the thrust force signature generated during the drilling of CFRP/Al7075-T6. Based on ANOVA, it is found that the maximum thrust force for both CFRP and Al7075-T6 are highly dependent on the feed rate. Through the analysis of maximum thrust force, supported by hole diameter error, hole surface roughness, and chip formation, it is found that the optimum tool parameters selection includes a helix angle of 30°, primary clearance angle of 6°, point angle of 130°, chisel edge angle of 30°, speed of 2600 rev/min and feed rate of 0.05 mm/rev. The optimum parameters obtained in this study are benchmarked against existing industry practice of the capability to produce higher hole quality and efficiency, which is set at 2600 rev/min for speed and 0.1 mm/rev for feed rate.
      Citation: Journal of Composites Science
      PubDate: 2021-07-17
      DOI: 10.3390/jcs5070189
      Issue No: Vol. 5, No. 7 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 190: Recent Advances in Two-Dimensional
           Transition Metal Dichalcogenide Nanocomposites Biosensors for Virus
           Detection before and during COVID-19 Outbreak

    • Authors: Ching Ying Katherine Lam, Qin Zhang, Bohan Yin, Yingying Huang, Hui Wang, Mo Yang, Siu Hong Dexter Wong
      First page: 190
      Abstract: The deadly Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) outbreak has become one of the most challenging pandemics in the last century. Clinical diagnosis reports a high infection rate within a large population and a rapid mutation rate upon every individual infection. The polymerase chain reaction has been a powerful and gold standard molecular diagnostic technique over the past few decades and hence a promising tool to detect the SARS-CoV-2 nucleic acid sequences. However, it can be costly and involved in complicated processes with a high demand for on-site tests. This pandemic emphasizes the critical need for designing cost-effective and fast diagnosis strategies to prevent a potential viral source by ultrasensitive and selective biosensors. Two-dimensional (2D) transition metal dichalcogenide (TMD) nanocomposites have been developed with unique physical and chemical properties crucial for building up nucleic acid and protein biosensors. In this review, we cover various types of 2D TMD biosensors available for virus detection via the mechanisms of photoluminescence/optical, field-effect transistor, surface plasmon resonance, and electrochemical signals. We summarize the current state-of-the-art applications of 2D TMD nanocomposite systems for sensing proteins/nucleic acid from different types of lethal viruses. Finally, we identify and discuss the advantages and limitations of TMD-based nanocomposites biosensors for viral recognition.
      Citation: Journal of Composites Science
      PubDate: 2021-07-18
      DOI: 10.3390/jcs5070190
      Issue No: Vol. 5, No. 7 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 191: Enhanced Tensile Strength of
           Monolithic Epoxy with Highly Dispersed TiO2-Graphene Nanocomposites

    • Authors: Yanshuai Wang, Siyao Guo, Biqin Dong, Feng Xing
      First page: 191
      Abstract: The functionalization of graphene has been reported widely, showing special physical and chemical properties. However, due to the lack of surface functional groups, the poor dispersibility of graphene in solvents strongly limits its engineering applications. This paper develops a novel green “in-situ titania intercalation” method to prepare a highly dispersed graphene, which is enabled by the generation of the titania precursor between the layer of graphene at room temperature to yield titania-graphene nanocomposites (TiO2-RGO). The precursor of titania will produce amounts of nano titania between the graphene interlayers, which can effectively resist the interfacial van der Waals force of the interlamination in graphene for improved dispersion state. Such highly dispersed TiO2-RGO nanocomposites were used to modify epoxy resin. Surprisingly, significant enhancement of the mechanical performance of epoxy resin was observed when incorporating the titania-graphene nanocomposites, especially the improvements in tensile strength and elongation at break, with 75.54% and 176.61% increases at optimal usage compared to the pure epoxy, respectively. The approach presented herein is easy and economical for industry production, which can be potentially applied to the research of high mechanical property graphene/epoxy composite system.
      Citation: Journal of Composites Science
      PubDate: 2021-07-18
      DOI: 10.3390/jcs5070191
      Issue No: Vol. 5, No. 7 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 192: Innovative Carbon-Doped Composite
           Pavements with Sensing Capability and Low Environmental Impact for
           Multifunctional Infrastructures

    • Authors: Hasan Borke Birgin, Antonella D’Alessandro, Simon Laflamme, Filippo Ubertini
      First page: 192
      Abstract: Recently, smart composites that serve as multi-functional materials have gained popularity for structural and infrastructural applications yielding condition assessment capabilities. An emerging application is the monitoring and prediction of the fatigue of road infrastructure, where these systems may benefit from the ability to detect and estimate vehicle loads via weigh-in-motion (WIM) sensing without interrupting the traffic flow. However, off-the-shelf applications of WIM can be improved in terms of cost and durability, both on the hardware and software sides. This study proposes a novel multi-functional pavement material that can be utilized as a pavement embedded weigh-in-motion system. The material consists of a composite fabricated using an eco-friendly synthetic binder material called EVIzero, doped with carbon microfiber inclusions. The composite material is piezoresistive and, therefore, has strain-sensing capabilities. Compared to other existing strain-sensing structural materials, it is not affected by polarization and exhibits a more rapid response time. The study evaluates the monitoring capabilities of the novel composite according to the needs of a WIM system. A tailored data acquisition setup with distributed line electrodes is developed for the detection of moving loads. The aim of the paper is to demonstrate the sensing capabilities of the newly proposed composite pavement material and the suitability of the proposed monitoring system for traffic detection and WIM. Results demonstrate that the material is promising in terms of sensing and ready to be implemented in the field for further validation in the real world.
      Citation: Journal of Composites Science
      PubDate: 2021-07-20
      DOI: 10.3390/jcs5070192
      Issue No: Vol. 5, No. 7 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 193: Vanadium Dioxide–Iridium Composite
           Development: Specific Near Infrared Surface Plasmon Resonance

    • Authors: Adrian Ionut Bercea, Corinne Champeaux, Catalin Daniel Constantinescu, Frédéric Dumas-Bouchiat
      First page: 193
      Abstract: This work serves as a roadmap for the development of a Vanadium dioxide (VO2)–Iridium composite based on the self-assembly of closely packed colloidal polystyrene microspheres (P-spheres) coupled with a Pulsed Laser Deposition (PLD) process. The self-assembly of a monolayer of PS is performed on an Al2O3-c substrate, using an adapted Langmuir–Blodgett (LB) process. Then, on the substrate covered with P-spheres, a 50-nanometer Iridium layer is deposited by PLD. The Iridium deposition is followed by the removal of PS with acetone, revealing an array of triangular shaped metallic elements formed on the underlaying substrate. In a last deposition step, 50-, 100- and 200-nanometer thin films of VO2 are deposited by PLD on top of the substrates covered with the Iridium quasi-triangles, forming a composite. Adapting the size of the P-spheres leads to control of both the size of the Iridium micro-triangle and, consequently, the optical transmittance of the composite. Owing to their shape and size the Iridium micro-triangles exhibit localized surface plasmon resonance (LSPR) characterized by a selective absorption of light. Due to the temperature dependent properties of VO2, the LSPR properties of the composite can be changeable and tunable.
      Citation: Journal of Composites Science
      PubDate: 2021-07-20
      DOI: 10.3390/jcs5070193
      Issue No: Vol. 5, No. 7 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 194: Urethane Diols through Non-Isocyanate
           Approach and Their Application in MF Coating

    • Authors: Kuanchen Huang, Zichen Ling, Qixin Zhou
      First page: 194
      Abstract: In this work, two urethane diols with different middle chain lengths were prepared by the non-isocyanate approach from 1,4-diaminobutane or 1,6-diaminohexane with ethylene cyclic carbonate at room temperature without the aid of a catalyst. Different weight percentages of hexa(methoxymethyl) melamine (HMMM) crosslinker was mixed with urethane diols then cured under elevated temperature to generate the melamine-formaldehyde (MF) coating films. Two different linear diols without urethane linkage were chosen to crosslink with HMMM as the control group. The mechanical properties of these MF coatings were investigated by tensile test, adhesion test, and conical mandrel bend test. It was found that coatings incorporated with urethane diols exhibited enhanced mechanical properties and flexibility. These properties were also influenced by the weight percentage of HMMM crosslinker. This study provided a facile non-isocyanate way to produce urethane diols and successfully applied them in MF coating.
      Citation: Journal of Composites Science
      PubDate: 2021-07-20
      DOI: 10.3390/jcs5070194
      Issue No: Vol. 5, No. 7 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 285: Crashworthiness of a Composite Bladder
           Fuel Tank for a Tilt Rotor Aircraft

    • Authors: Carmen Simona Paciello, Claudio Pezzella, Marika Belardo, Simone Magistro, Francesco Di Caprio, Vincenzo Musella, Giuseppe Lamanna, Luigi Di Palma
      First page: 285
      Abstract: The fulfilment of the crash is a demanding requirement for a Tiltrotor. Indeed, such a kind of aircraft, being a hybrid between an airplane and a helicopter, inherits the requirements mainly from helicopters (EASA CS 29) due to its hovering ability. In particular, the fuel storage system must be designed in such a manner that it is crash resistant, under prescribed airworthiness requirements, in order to avoid the fuel leakage during such an event, preventing fire and, thus, increasing the survival chances of the crew and the passengers. The present work deals with the evaluation of crashworthiness of the fuel storage system of a Tiltrotor (bladder tank), and, in particular, it aims at describing the adopted numerical approach and some specific results. Crash resistance requirements are considered from the earliest design stages, and for this reason they are mainly addressed from a numerical point of view and by simulations that treat both single components and small/medium size assemblies. The developed numerical models include all the main parts needed for simulating the structural behavior of the investigated wing section: the tank, the structural components of the wing, the fuel sub-systems (fuel lines, probes, etc.) and the fuel itself. During the crash event there are several parts inside the tanks that can come into contact with the tank structure; therefore, it is necessary to evaluate which of these parts can be a damage source for the tank itself and could generate fuel loss. The SPH approach has been adopted to discretise fuel and to estimate the interaction forces with respect to the tank structure. Experimental data were used to calibrate the fuel tank and foam material models and to define the acceleration time-history to be applied. Thanks to the optimized foam’s configuration, the amount of dissipated impact energy is remarkable, and the evaluation of tanks/fuel system stress distribution allows estimating any undesired failure due to a survivable crash event.
      Citation: Journal of Composites Science
      PubDate: 2021-10-22
      DOI: 10.3390/jcs5110285
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 286: Mechanical and Microstructural
           Assessment of Inhomogeneities in Oxide Ceramic Matrix Composites Detected
           by Air-Coupled Ultrasound Inspection

    • Authors: Jan Roßdeutscher, Peter Mechnich, Ferdinand Flucht, Yuan Shi, Raouf Jemmali
      First page: 286
      Abstract: Ceramic Matrix Composites (CMC) are promising materials for high-temperature applications where damage tolerant failure behavior is required. Non-destructive testing is essential for process development, monitoring, and quality assessment of CMC parts. Air-coupled ultrasound (ACU) is a fast and cost-efficient tool for non-destructive inspections of large components with respect to the detection of material inhomogeneities. Even though ACU inspection is usually used for visual inspection, the interpretation of C-scan images is often ambiguous with regard to critical defects and their impact on local material properties. This paper reports on a new approach to link the local acoustic damping of an oxide CMC plate obtained from ACU analysis with subsequent destructive mechanical testing and microstructural analyses. Local damping values of bending bars are extracted from ACU maps and compared with the results of subsequent resonant frequency damping analysis and 3-point bending tests. To support data interpretation, the homogeneous and inhomogeneous CMC areas detected in the ACU map are further analyzed by X-ray computed tomography and scanning electron microscopy. The results provide strong evidence that specific material properties such as Young’s modulus are not predictable from ACU damping maps. However, ACU shows a high, beneficial sensitivity for narrow but large area matrix cracks or delaminations, i.e., local damping is significantly correlated with specific properties such as shear moduli and bending strengths.
      Citation: Journal of Composites Science
      PubDate: 2021-10-23
      DOI: 10.3390/jcs5110286
      Issue No: Vol. 5, No. 11 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 253: The Use of Agricultural Waste in the
           Modification of Poly(lactic acid)-Based Composites Intended for 3D
           Printing Applications. The Use of Toughened Blend Systems to Improve
           Mechanical Properties

    • Authors: Jacek Andrzejewski, Karolina Grad, Wojciech Wiśniewski, Joanna Szulc
      First page: 253
      Abstract: The presented research focused on improving the mechanical properties of PLA-based composites reinforced with buckwheat husks (BH) particles. The research work was carried out in two stages. Firstly, the blend was prepared with the addition of polybutylene adipate terephthalate (PBAT) and thermoplastic starch (TPS), manufactured by injection molding technique, then the selected materials were prepared with the addition of BH filler, and the samples were prepared using the fused deposition modeling method (FDM). All samples were subjected to the assessment of material properties. Thermal and thermomechanical properties were evaluated using differential scanning calorimetry analysis (DSC) and dynamic thermal mechanical analysis (DMTA). Mechanical characteristic was evaluated using static tensile and flexural measurements and Charpy impact resistance tests. The research was supplemented with scanning electron microscopy analysis (SEM). It was found that the addition of PBAT and TPS greatly improves impact strength and elongation, especially with the addition of reactive compatibilizer. As expected, TPS, PBAT, and BH reduced the stiffness of the composites during DMTA testing. The presence of BH particles in the polymer matrix was observed to improve the crystallization behavior of PLA. The optimal content of BH filler in the composite was found to be 10%, which allowed to preserve good mechanical properties.
      Citation: Journal of Composites Science
      PubDate: 2021-09-22
      DOI: 10.3390/jcs5100253
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 254: Tribological Characterization of
           Carbon Nanotube/Aluminum Functionally Graded Materials Fabricated by
           Centrifugal Slurry Methods

    • Authors: Hideaki Tsukamoto
      First page: 254
      Abstract: Although carbon nanotube (CNT) is a promising material due to its excellent mechanical and functional properties, CNT has not been effectively used for high performance composites due to the degradation of its mechanical properties as a result of insufficient dispersibility of CNT in its matrix. In this study, CNT/aluminum (Al) matrix functionally graded materials (FGMs) were fabricated by centrifugal slurry methods. The dispersion of CNT was carried out with the solvent of dimethylacetamide (DMAs), and the dispersant of potassium carbonate (K2CO3) under ultrasonic sonication conditions. Tribological characteristics on the FGMs were investigated using a ball-on-disk tribometer. It was demonstrated that the presence of CNT contributed to an increase of the coefficients of friction and an enhancement of wear resistances.
      Citation: Journal of Composites Science
      PubDate: 2021-09-24
      DOI: 10.3390/jcs5100254
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 255: Effect of Ce Content on Properties of
           Al-Ce-Based Composites by Powder-in-Tube Method

    • Authors: Mairym Vázquez, Oscar Marcelo Suárez, Michael Thompson, Haneul Jang, Na Gong, David Weiss, Orlando Rios
      First page: 255
      Abstract: Al-Ce based alloys have gained recent interest and have proven to have excellent strength without heat treatment and high thermal stability. Challenges with the production of Al-Ce samples from elemental powders arise due to the elemental material before alloying being susceptible to rapid oxidation. The methodology for making superconductive wire, powder-in-tube, was used as a consolidate Al and Ce elemental powder, and Al-8 wt % Ce-10 wt % Mg composite powder into bulk nanostructured material. Powder samples are fabricated in an inert controlled atmosphere, then sealed in a tube to avoid oxidation of powders. Therefore, most of the powder is used without much loss. We used 316 stainless-steel tubes as a sheathing material. For Al-xCe wt % (x = 8 to 14) samples of elemental powder, liquid phase sintering was used and for Al-Ce-Mg powder solid-state sintering. Characterization of the bulk consolidated material after sintering, and before and after heat treatment, was made using optical and Scanning Electron Microscope imaging, Energy Dispersive Spectroscopy, Microhardness and Rockwell Hardness test. We demonstrated that microstructure stability in Al-Ce-based specimens can be retained after thermomechanical processing. Densification was achieved and oxidation of powder was avoided in most samples. In addition, we found that Fe and Ni in the sheathing material react with Al in the process, and Ce concentration modifies the reactivity the sheath.
      Citation: Journal of Composites Science
      PubDate: 2021-09-25
      DOI: 10.3390/jcs5100255
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 256: Reducing the Weakening Effect in
           Fibre-Reinforced Polymers Caused by Integrated Film Sensors

    • Authors: Alexander Kyriazis, Julia Feder, Korbinian Rager, Chresten von der Heide, Andreas Dietzel, Michael Sinapius
      First page: 256
      Abstract: Integrating foil sensors into fibre-reinforced plastics offers the advantage of making manufacturing measurable with spatial resolution and thus simplifies quality control. One challenge here is the possible negative influence of the integrated sensors on the mechanical behaviour of the structure. This article shows how the different parts of a film sensor influence important mechanical strength parameters of fibre composites. A comparison of two thermoplastic carrier films shows that by choosing polyetherimide (PEI) instead of polyimide (PI), a considerably more advantageous failure behaviour of the composite is achieved. While integrated PI films reduce the interlaminar shear strength by 68%, no impairment is noticeable due to PEI films. For the critical energy release rate, PEI-based film sensors even lead to a significant increase, while a significant deterioration of 85% can be observed for PI-based sensors. However, not only the film substrate plays a decisive role for the interlaminar shear strength, but also the sensor structures themselves. In this article, sensor structures made of gold were investigated. The decisive parameter for the impairment seems to be the area share of gold structures in the sensor. For a sensor pattern made of gold lines with an area filling of 50%, a reduction of the interlaminar shear strength of up to 25% was observed depending on the angle between the shear stress and the gold lines. No impairment was observed for sensor structures with less gold area. The results show that PEI substrates can be a superior alternative for sensor integration into fibre composites and suggest that there is a trade-off between sensitivity and degradation of mechanical properties when designing interdigital sensors.
      Citation: Journal of Composites Science
      PubDate: 2021-09-28
      DOI: 10.3390/jcs5100256
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 257: Influence of Component Ratio on
           Thermal and Mechanical Properties of Terpenoid-Sulfur Composites

    • Authors: Charini P. Maladeniya, Rhett C. Smith
      First page: 257
      Abstract: Terpenoids are potentially sustainable replacements for petrochemical olefins. Sulfur is a waste product produced in large quantities from fossil fuel refining. Several composites with attractive properties have recently been made from terpenoids and sulfur. This report details the extent to which the ratio of sulfur to terpenoid and the terpenoid olefin content influences the thermal and mechanical properties of such terpenoid-sulfur composites. The terpenoids selected were diunsaturated geraniol and triunsaturated farnesol that, upon their inverse vulcanization with elemental sulfur, yield composites GerSx and FarSx, respectively (x = wt % sulfur). The wt % sulfur in the monomer feed was varied from 30–95 for this study, providing twelve materials. Mechanical analysis of these materials was undertaken by compressive and tensile strength techniques. Differential scanning calorimetric analysis revealed both polymeric and orthorhombic sulfur present in the materials with glass transition temperatures (Tg) of −37 °C to −13 °C and melt temperatures (Tm) of 119 to 104 °C. The crystallinity of composites decreases as the weight fraction of sulfur decreases and composites having the highest olefin content exhibit no detectable crystalline microstructures. The compressive strength of the materials showed increasing strength for higher olefin-content materials for both GerSx (with compressive strength of up to 32 MPa) and FarSx (with compressive strength of up to 43 MPa). The improved strength with increasing olefin content levels off at around 80–85% of terpenoid, after which point both tensile and compressive strength diminish.
      Citation: Journal of Composites Science
      PubDate: 2021-09-28
      DOI: 10.3390/jcs5100257
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 258: The Effects of Some
           Phosphorus-Containing Fire Retardants on the Properties of Glass
           Fibre-Reinforced Composite Laminates Made from Blends of Unsaturated
           Polyester and Phenolic Resins

    • Authors: Latha Krishnan, Baljinder. K. Kandola, John R. Ebdon
      First page: 258
      Abstract: This study investigated the effects of phosphorus fire retardants (FRs) in matrices from co-cured blends of an unsaturated polyester (UP) with inherently fire-retardant phenolic resoles (PH) on the mechanical and flammability properties of resultant glass fibre-reinforced composites. Three different phenolic resoles with UP have been used: (i) an ethanol soluble (PH-S), (ii) an epoxy-functionalised (PH-Ep), and (iii) an allyl-functionalised resin (PH-Al) with two different phosphorus FRs: resorcinol bis (diphenyl phosphate) (RDP) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The flammabilities of the resultant composites were evaluated using cone calorimetry and the UL-94 test. Cone calorimetric results showed reductions in peak heat release rate (PHRR) and total heat released (THR) as expected compared to those of UP and respective UP/PH composite laminates without FRs. UL-94 tests results showed that while all composites had HB rating, FR containing samples self-extinguished after removal of the flame. The mechanical properties of the composites were evaluated using flexural, tensile and impact tests. All FRs reduced the mechanical properties, and the reduction in mechanical properties was more severe in UP/PH-S (least compatible blends) composites with FRs than in UP/PH-Al (most compatible blends) composites with FRs. Amongst the different composites, those from UP/PH-Al with DOPO showed the best fire retardancy with little deterioration of mechanical performance.
      Citation: Journal of Composites Science
      PubDate: 2021-09-28
      DOI: 10.3390/jcs5100258
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 259: Toughening of Bioceramic Composites
           for Bone Regeneration

    • Authors: Zahid Abbas, Massimiliano Dapporto, Anna Tampieri, Simone Sprio
      First page: 259
      Abstract: Bioceramics are widely considered as elective materials for the regeneration of bone tissue, due to their compositional mimicry with bone inorganic components. However, they are intrinsically brittle, which limits their capability to sustain multiple biomechanical loads, especially in the case of load-bearing bone districts. In the last decades, intense research has been dedicated to combining processes to enhance both the strength and toughness of bioceramics, leading to bioceramic composite scaffolds. This review summarizes the recent approaches to this purpose, particularly those addressed to limiting the propagation of cracks to prevent the sudden mechanical failure of bioceramic composites.
      Citation: Journal of Composites Science
      PubDate: 2021-09-29
      DOI: 10.3390/jcs5100259
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 260: Improving the Combustion Properties of
           Corncob Biomass via Torrefaction for Solid Fuel Applications

    • Authors: Segun Emmanuel Ibitoye, Tien-Chien Jen, Rasheedat Modupe Mahamood, Esther Titilayo Akinlabi
      First page: 260
      Abstract: The overdependence on fossils as the primary energy source has led to climate change, global warming, and the emission of greenhouse gas. As a result, the United Nations, while setting the goals for the year 2030, has made the provision of a green environment and energy one of the top priorities. In this study, the suitability of corncob for green energy production was investigated. The improvement of corncob’s thermal and combustion properties via the torrefaction process was considered for solid fuel applications. The raw corncob was collected, sorted, and dried for seven days before being used for the torrefaction experiment. Different torrefaction temperatures (200, 240, and 260 °C) and residence times (20, 40, 60 min) were studied. There was no particle reduction—samples were torrefied as collected (whole corncob). The results show that torrefaction temperature and residence time affect the torrefaction products yields along with their properties. Thermal and combustion properties were improved with an increase in torrefaction temperature and residence time. The higher heating value and energy density of the torrefied corncob varied between 17.26 and 18.89 MJ/kg, and 3.23 and 5.66 GJ/m3, respectively. High torrefaction temperature and residence time lead to low solid yield; however, liquid and gas yields increase with torrefaction temperature and residence time. The solid yields varied from 27.57 to 52.23%, while the liquid and gas yields varied from 31.56 to 44.78% and 16.21 to 27.65%, respectively. The properties of corncob improve after torrefaction and are suitable for solid fuel application.
      Citation: Journal of Composites Science
      PubDate: 2021-10-01
      DOI: 10.3390/jcs5100260
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 261: Optimization of Milling Parameters of
           Unmodified Calotropis Procera Fiber-Reinforced PLA Composite (UCPFRPC)

    • Authors: Hassan K. Langat, Fredrick M. Mwema, James N. Keraita, Esther T. Akinlabi, Job M. Wambua, Tien-Chien Jen
      First page: 261
      Abstract: This study involves the optimization of the milling parameters of unmodified Calotropis Procera fiber-reinforced PLA composite (UCPFRPC). The material is prepared from the combination of 20% Calotropis-Procera and 80% of PLA by weight. The experiments are designed using the Taguchi methodology, where 16 experiments are obtained using the spindle rotational speed, depth of cut, and feed rate as the parameters. These experiments were conducted while obtaining thermal images using an infrared camera and recording the machining time. The change in mass was then determined and the material removal rate computed. The machined workpieces were then investigated for surface roughness. The study shows that the optimal milling parameters in the machining of UCPFRPC for the lowest surface roughness are 400 rpm, 400 mm/min, and 0.2 mm, for the rotational spindle speed, feed rate, and depth of cut. The parameters were 400 rpm, 100 mm/min, and 1.2 mm for the largest MRR, and 400 rpm, 400 mm/min, and 0.2 mm for the least average milling temperature. In all the responses, the depth of cut is the most significant factor.
      Citation: Journal of Composites Science
      PubDate: 2021-10-01
      DOI: 10.3390/jcs5100261
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 262: Carbonization Temperature and Its
           Effect on the Mechanical Properties, Wear and Corrosion Resistance of
           Aluminum Reinforced with Eggshell

    • Authors: Ndudim H. Ononiwu, Chigbogu G. Ozoegwu, Nkosinathi Madushele, Esther T. Akinlabi
      First page: 262
      Abstract: In this paper, the effect of the carbonization temperature on the mechanical properties, density, wear and corrosion resistance of AA 6063 reinforced with eggshells was investigated. The selected fabrication route for this investigation was stir casting while the weight fraction of the eggshells was kept constant at 5 wt.%. The carbonization temperature was varied at 900, 1000, 1100, and 1200 °C. The microstructure revealed that the eggshells were fairly uniformly dispersed on the individual grains and along the grain boundaries of the base metal. It was also shown that the presence of agglomeration increased with increasing carbonization temperature. The densities of the eggshell-reinforced AMCs were lower than that of the base metal. The analysis of the microhardness showed an improvement of 40.79, 22.93, 25.70, and 29.43% for the 900, 1000, 1100, and 1200 °C carbonized eggshell samples, respectively. The compressive strength studies showed that the addition of carbonized eggshells improved the compressive strength of the composites compared to the base metal. The tribology studies showed that the wear resistance improved for the 900 and 1200 °C samples, while the electrochemical studies revealed that the corrosion resistance improved for the 900 and 1000 °C samples only.
      Citation: Journal of Composites Science
      PubDate: 2021-10-01
      DOI: 10.3390/jcs5100262
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 263: Polymer Blends and Polymer
           Nanocomposites for Photovoltaic (PV) Cells and an Investigation of the
           Material Deposition Techniques in PV Cell Fabrication

    • Authors: George Ntanovasilis, Ioannis Zaverdas, Tarig Ahmed, Foivos Markoulidis, Constantina Lekakou
      First page: 263
      Abstract: Polymer photovoltaics (PV) offer the advantage of low-cost, mass-produced, flexible PV films, but they generally suffer from a low-power conversion efficiency (PCE) compared to silicon. This paper studies ITO/PEDOT:PSS/bulk heterojunction/Al PV cells, where two different bulk heterojunction blends are researched: P3HT/PC61BM and PCDTBT/PC70BM. The addition of multiwall carbon nanotubes (CNT) is explored as a conductive network to accelerate the electron transport and extraction to the outer aluminium current collector while reducing the chance of charge recombinations. Several layer deposition techniques are investigated: spin coating and casting, as well as techniques that would induce transverse orientation of polymer grains, including inkjet printing, electrophoresis and the application of a transverse AC field during annealing. Transverse orientation techniques produced architectures that would facilitate charge transport without recombinations, but it is recommended to avoid such techniques for the deposition of conductive PEDOT:PSS and CNT layers as they create a high surface roughness that leads to short circuiting. The best performing PV cell is the ITO/PEDOT:PSS/PCDTBT/PC70BM/CNT/Al structure with a PCE of 11%.
      Citation: Journal of Composites Science
      PubDate: 2021-10-09
      DOI: 10.3390/jcs5100263
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 264: Numerical and Experimental Evaluation
           of Mechanical and Ring Stiffness Properties of Preconditioning Underground
           Glass Fiber Composite Pipes

    • Authors: Mohamed K. Hassan, Ahmed F. Mohamed, Khalil Abdelrazek Khalil, Mohammed Y. Abdellah
      First page: 264
      Abstract: The mechanical and ring stiffness of glass fiber pipes are the most determining factors for their ability to perform their function, especially in a work environment with difficult and harmful conditions. Usually, these pipes serve in rough underground environments of desert and petroleum fields; therefore, they are subjected to multi-type deterioration and damage agents. In polymers and composite materials, corrosion is identified as the degradation in their properties. In this study, tension and compression tests were carried out before and after preconditioning in a corrosive agent for 60 full days to reveal corrosion influences. Moreover, the fracture toughness is measured using a standard single edge notch bending. Ring stiffness of such pipes which, are considered characteristic properties, is numerically evaluated using the extended finite element method before and after preconditioning. The results reported that both tensile and compressive strengths degraded nearly more than 20%. Besides the fracture toughness decrease, the stiffness ring strength is reduced, and the finite element results are in good agreement with the experimental findings.
      Citation: Journal of Composites Science
      PubDate: 2021-10-10
      DOI: 10.3390/jcs5100264
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 265: Post-Fire Mechanical Properties of
           Concrete Reinforced with Spanish Broom Fibers

    • Authors: Sandra Juradin, Lidia Karla Vranješ, Dražan Jozić, Ivica Boko
      First page: 265
      Abstract: In this study, we conducted an initial investigation of the post-fire mechanical properties of concrete reinforced with Spanish broom fibers. The mechanical properties were determined at room temperature, and the post-fire mechanical properties were determined at elevated temperature, so that the fire resistance of the concrete could be determined. Five mixtures were considered: three with differently treated Spanish broom fibers, a polypropylene fiber mixture, and a reference concrete mixture. The concrete and reinforced concrete samples were first dried to 100 °C, then heated to 400 °C, and left to cool to room temperature. The samples were tested immediately and 96 h after cooling. The compressive strength, weight loss, ultrasonic pulse velocity, and dynamic modulus of elasticity were determined and compared. The cross-sectional images of the concrete samples captured through an optical microscope were observed and analyzed. The changes in fiber structure were monitored by TG/DTG analysis. The results of the study indicate that even the reference concrete mixture did not have satisfactory residual properties. The reinforced concretes did not improve the residual properties of the reference concrete, but reduced the spalling and explosive failure performance under a compressive load. The concrete reinforced with Spanish broom fibers showed improved residual properties compared with concrete reinforced with polypropylene fibers.
      Citation: Journal of Composites Science
      PubDate: 2021-10-11
      DOI: 10.3390/jcs5100265
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 266: Inverse Proportionality of Thermal
           Conductivity and Complex Permittivity to Filler-Diameter in Epoxy Resin
           Composites with Silica

    • Authors: Yoshimichi Ohki, Naoshi Hirai, Takahiro Umemoto, Hirotaka Muto
      First page: 266
      Abstract: We prepared six kinds of epoxy resin nanocomposites with silica and an epoxy resin with no silica. The nanocomposites contain silica with different diameters (10, 50, and 100 nm) while their silica contents are 1, 5, 10, and 20 vol%. At 25 and 100 °C, the thermal conductivity has a nearly proportional dependence on the silica content and exhibits an almost reciprocal proportionality to the diameter of the silica. The latter result indicates that the interaction at filler-resin interfaces plays a significant role in heat transfer. However, this view contradicts an easy-to-understand thought that the filler-resin interfaces should work as a barrier for heat transfer. This in turn indicates that the interaction at filler-resin interfaces controls the bulk properties of the resin when the filler is in a nm size. Although the dielectric constant increases with the addition of the silica filler, its increment from the resin with no silica is the smallest in the resin with the 10-nm silica. Therefore, the addition of the 10-nm silica is adequate for electrical insulation purposes.
      Citation: Journal of Composites Science
      PubDate: 2021-10-11
      DOI: 10.3390/jcs5100266
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 267: Synthesis and Characterization of
           Novel Fe3O4/PVA/Eggshell Hybrid Nanocomposite for Photodegradation and
           Antibacterial Activity

    • Authors: Piyush Kumar Gupta, Senthilkumar Palanisamy, Tamilarasi Gopal, Ranjithkumar Rajamani, Soumya Pandit, Somya Sinha, Vijay Kumar Thakur
      First page: 267
      Abstract: In the 21st century, hybrid nanocomposites were widely used in bioelectronic, biosensing, photocatalytic, and biomedical applications. In the present study, we fabricated a novel Fe3O4/PVA/Eggshell hybrid nanocomposite and physicochemically characterized it using powder XRD, EDS, FTIR, VSM, and HR-TEM analysis. The XRD spectrum revealed the crystalline and FCC configuration of Fe3O4 NPs with average crystal size of 16.28 nm, and the HRTEM image indicates the prepared hybrid nanocomposite is of spherical shape with less agglomeration. This hybrid nanocomposite showed a significant photodegradation property in degrading organic pollutants such as congo red and crystal violet dyes under the sunlight irradiation. In addition, the hybrid nanocomposite also displayed a potent antibacterial property against different Gram +ve and Gram −ve bacterial pathogens. This study provides a significant example in the overview of fabrication of cost effectively, eco-friendly, and multiple-application hybrid nanocomposites through eggshell membrane fibers.
      Citation: Journal of Composites Science
      PubDate: 2021-10-12
      DOI: 10.3390/jcs5100267
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 268: Strain-Mediated Magneto-Electric
           Effects in Coaxial Nanofibers of Y/W-Type Hexagonal Ferrites and
           Ferroelectrics

    • Authors: Ying Liu, Peng Zhou, Bingfeng Ge, Jiahui Liu, Jitao Zhang, Wei Zhang, Tianjing Zhang, Gopalan Srinivasan
      First page: 268
      Abstract: Nanofibers of Y- or W-type hexagonal ferrites and core–shell fibers of hexagonal ferrites and ferroelectric lead zirconate titanate (PZT) or barium titanate (BTO) were synthesized by electrospinning. The fibers were found to be free of impurity phases, and the core–shell structure was confirmed by electron and scanning probe microscopy. The values of magnetization of pure hexagonal ferrite fibers compared well with bulk ferrite values. The coaxial fibers showed good ferroelectric polarization, with a maximum value of 0.85 μC/cm2 and 2.44 μC/cm2 for fibers with BTO core–Co2W shell and PZT core–Ni2Y shell structures, respectively. The magnetization, however, was much smaller than that for bulk hexaferrites. Magneto-electric (ME) coupling strength was characterized by measuring the ME voltage coefficient (MEVC) for magnetic field-assembled films of coaxial fibers. Among the fibers with Y-type, films with Zn2Y showed a higher MEVC than films with Ni2Y, and fibers with Co2W had a higher MEVC than that of those with Zn2W. The highest MEVC of 20.3 mV/cm Oe was measured for Co2W–PZT fibers. A very large ME response was measured in all of the films, even in the absence of an external magnetic bias field. The fibers studied here have the potential for use in magnetic sensors and high-frequency device applications.
      Citation: Journal of Composites Science
      PubDate: 2021-10-13
      DOI: 10.3390/jcs5100268
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 269: Thermal, X-ray Diffraction and
           Oedometric Analyses of Silt-Waste/NaOH-Activated Metakaolin Geopolymer
           Composite

    • Authors: Daniele Moro, Riccardo Fabbri, Jennifer Romano, Gianfranco Ulian, Antonino Calafato, Abbas Solouki, Cesare Sangiorgi, Giovanni Valdrè
      First page: 269
      Abstract: The present research investigates the possibility to create a silt-waste reinforced composite through a NaOH-activated, metakaolin-based geopolymerization process. In this regard, we used thermal exo–endo analysis, X-ray diffraction (XRD), and oedometric mechanical tests to characterize the produced composites. In our experimental conditions, the tested material mixtures presented exothermic peaks with maximum temperatures of about 100 °C during the studied geopolymerization process. In general, the XRD analyses showed the formation of amorphous components and new mineral phases of hydrated sodalite, natrite, thermonatrite and trona. From oedometric tests, we observed a different behavior of vertical deformation related to pressure (at RT) for the various produced composites. The present work indicated that the proposed geopolymerization process to recycle silt-waste produced composite materials with various and extended mineralogy and chemical–physical properties, largely depending on both the precursors and the specific alkaline-activating solution. Thermal analysis, XRD, and oedometric mechanical tests proved to be fundamental to characterize and understand the behavior of the newly formed composite material.
      Citation: Journal of Composites Science
      PubDate: 2021-10-13
      DOI: 10.3390/jcs5100269
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 270: Effects of Surface Modification with
           Stearic Acid on the Dispersion of Some Inorganic Fillers in PE Matrix

    • Authors: Thanh Tung Nguyen, Van Khoi Nguyen, Thi Thu Ha Pham, Thu Trang Pham, Trung Duc Nguyen
      First page: 270
      Abstract: To evaluate the effects of surface modification with stearic acid on the dispersion of some inorganic fillers in polyethylene (PE) matrix, masterbatches containing 20–40 wt% of stearic acid uncoated and coated inorganic fillers and the linear low-density polyethylene (LLDPE) films containing 3–7% stearic acid uncoated and coated inorganic fillers were prepared. Two types of inorganic fillers used in the masterbatch included bentonite and silica. The structural change of inorganic fillers, whose surface was modified with stearic acid, was studied using IR spectroscopy. The dispersion of inorganic fillers in LLDPE matrix was evaluated using scanning electron microscope (masterbatch samples) and optical microscope (film samples). Changes in the melting temperature of LLDPE in the presence of inorganic fillers were evaluated by using differential scanning calorimeter (DSC). The mechanical properties of the films were evaluated according to ASTM D882. Surface-treated fillers with stearic acid dispersed in the masterbatches and films better than untreated fillers did. Stearic acid did not change the melting temperature of the filler/PE masterbatches. The mechanical properties of the films containing stearic acid coated fillers were higher than those containing unmodified fillers.
      Citation: Journal of Composites Science
      PubDate: 2021-10-13
      DOI: 10.3390/jcs5100270
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 271: Random Forest Modeling for Fly
           Ash-Calcined Clay Geopolymer Composite Strength Detection

    • Authors: Priyanka Gupta, Nakul Gupta, Kuldeep K. Saxena, Sudhir Goyal
      First page: 271
      Abstract: Geopolymer is an eco-friendly material used in civil engineering works. For geopolymer concrete (GPC) preparation, waste fly ash (FA) and calcined clay (CC) together were used with percentage variation from 5, 10, and 15. In the mix design for geopolymers, there is no systematic methodology developed. In this study, the random forest regression method was used to forecast compressive strength and split tensile strength. The input content involved were caustic soda with 12 M, 14 M, and 16 M; sodium silicate; coarse aggregate passing 20 mm and 10 mm sieve; crushed stone dust; superplasticizer; curing temperature; curing time; added water; and retention time. The standard age of 28 days was used, and a total of 35 samples with a target-specified compressive strength of 30 MPa were prepared. In all, 20% of total data were trained, and 80% of data testing was performed. Efficacy in terms of mean absolute error (MAE), root mean square error (RMSE), coefficient of determination (R2), and MSE (mean squared error) is suggested in the model. The results demonstrated that the RFR model is likely to predict GPC compressive strength (MAE = 1.85 MPa, MSE = 0.05 MPa, RMSE = 2.61 MPa, and R2 = 0.93) and split tensile strength (MAE = 0.20 MPa, MSE = 6.83 MPa, RMSE = 0.24 MPa, and R2 = 0.90) during training.
      Citation: Journal of Composites Science
      PubDate: 2021-10-13
      DOI: 10.3390/jcs5100271
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 272: Effects of Resin/Filler Adhesion on
           the Thermal and Electrical Conductivity of Polyimide Nanocomposites

    • Authors: Yoshimichi Ohki, Naoshi Hirai
      First page: 272
      Abstract: With an aim to develop a good coil winding insulation film, fillers of boehmite alumina in the shape of a roughly rectangular plate were added with ratios of 10 and 20 wt% to polyimide. The filler surface was untreated or treated with a methacrylic or an epoxy silane coupling agent. Such prepared polyimide nanocomposites were subjected to various tests to measure the tensile strength, elastic modulus, complex permittivity, and thermal conductivity. It was found that samples with fillers treated using the methacrylic silane coupling agent have the strongest adhesion at the filler/polyimide interfaces and the lowest dielectric loss factor at high temperatures. A positive relationship between the filler/polyimide adhesion and the thermal conductivity is also indicated. These findings are significant since they indicate that the adhesion status at the filler/polymer interface exerts a strong influence on the thermal and electrical conduction processes in the polymer.
      Citation: Journal of Composites Science
      PubDate: 2021-10-14
      DOI: 10.3390/jcs5100272
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 273: Is Surface Metastability of Today’s
           Ceramic Bearings a Clinical Issue'

    • Authors: Alessandro Alan Porporati, Laurent Gremillard, Jérôme Chevalier, Rocco Pitto, Marco Deluca
      First page: 273
      Abstract: Recent studies on zirconia-toughened alumina (ZTA) evidenced that in vivo aged implants display a much higher monoclinic zirconia content than expected from in vitro simulations by autoclaving. At the moment, there is no agreement on the source of this discrepancy: Some research groups ascribe it to the effect of mechanical impact shocks, which are generally not implemented in standard in vitro aging or hip walking simulators. Others invoke the effect of metal transfer, which should trigger an autocatalytic reaction in the body fluid environment, accelerating the kinetics of tetragonal-to-monoclinic transformation in vivo. Extrapolations of the aging kinetics from high (autoclave) to in vivo temperature are also often disputed. Last, Raman spectroscopy is by far the preferred method to quantify the amount of monoclinically transformed zirconia. There are, however, many sources of errors that may negatively affect Raman results, meaning that the final interpretation might be flawed. In this work, we applied Raman spectroscopy to determine the monoclinic content in as-received and in vitro aged ZTA hip joint implants, and in one long-term retrieval study. We calculated the monoclinic content with the most used equations in the literature and compared it with the results of X-ray diffraction obtained on a similar probe depth. Our results show, contrary to many previous studies, that the long-term surface stability of ZTA ceramics is preserved. This suggests that the Raman technique does not offer consistent and unique results for the analysis of surface degradation. Moreover, we discuss here that tetragonal-to-monoclinic transformation is also necessary to limit contact damage and wear stripe extension. Thus, the surface metastability of zirconia-containing ceramics may be a non-issue.
      Citation: Journal of Composites Science
      PubDate: 2021-10-14
      DOI: 10.3390/jcs5100273
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 274: Flame Retardancy of Lightweight
           Sandwich Composites

    • Authors: Fabienne Samyn, Roland Adanmenou, Serge Bourbigot, Sophie Duquesne, Maude Jimenez, Marieke Van Marle, Sebastiaan Weij
      First page: 274
      Abstract: This study proposes an innovative solution to flame-retard a sandwich composite made of unsaturated polyester resin, glass fibre skins and polyester nonwoven core material. The strategy uses the core material as flame-retardant carrier, while the resin is also flame-retarded with aluminum trihydroxide (ATH). A screening of the fire-retardant performances of the core materials, covered with different types of phosphorous flame-retardant additives (phosphate, phosphinate, phosphonate), was performed using cone calorimetry. The best candidate was selected and evaluated in the sandwich panel. Great performances were obtained with ammonium polyphosphate (AP422) at 262 g/m2. The core material, when tested alone, did not ignite, and when used in the laminate, improved the fire behaviour by decreasing the peak of heat release rate (pHRR) and the total heat release (THR): the second peak in HRR observed for the references (full glass monolith and sandwich with the untreated core) was suppressed in this case. This improvement is attributed to the interaction occurring between the two FR additives, which leads to the formation of aluminophosphates, as shown using Electron Probe Micro-Analysis (EPMA), X-ray Diffraction (XRD) and solid-state 31P Nuclear Magnetic Resonance (NMR). The influence of the FR add-on on the core, as well as the ATH loading in the matrix, was studied separately to optimize the material performances in terms of smoke and heat release. The best compromise was obtained using AP422 at 182 g/m2 and 160 phr of ATH.
      Citation: Journal of Composites Science
      PubDate: 2021-10-14
      DOI: 10.3390/jcs5100274
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 275: Method for the Microstructural
           Characterisation of Unidirectional Composite Tapes

    • Authors: Nico Katuin, Daniël M. J. Peeters, Clemens A. Dransfeld
      First page: 275
      Abstract: The outstanding properties of carbon fibre-reinforced polymer composites are affected by the development of its microstructure during processing. This work presents a novel approach to identify microstructural features both along the tape thickness and through the thickness. Voronoi tessellation-based evaluation of the fibre volume content on cross-sectional micrographs, with consideration of the matrix boundary, is performed. The method is shown to be robust and is suitable to be automated. It has the potential to discriminate specific microstructural features and to relate them to processing behaviour removing the need for manufacturing trials.
      Citation: Journal of Composites Science
      PubDate: 2021-10-14
      DOI: 10.3390/jcs5100275
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 276: Triangular Functionally Graded Porous
           Moderately Thick Plates—Deformations and Free Vibrations

    • Authors: Aleksander Muc
      First page: 276
      Abstract: Since the finite element analysis of deformations for plates made of functionally graded materials cannot be carried out with the use of commercial FE packages, aconsistent method of analytical analysis is proposed in the paper. The method of the analysis is based on the application of the weighted residuals and the Bubnov–Galerkin method. The 2D formulation of moderately thick plates is adopted herein for classical and transverse shear deformation plate models (first and third order). Plate deformations subjected to uniform normalpressure and free vibrations are considered. The validity of the analytical model was verified by the comparison of results with FE analysis for isotropic plates. Two correction multipliers were proposed in order to take into account the unsymmetric composition of functionally graded porous plate walls.
      Citation: Journal of Composites Science
      PubDate: 2021-10-15
      DOI: 10.3390/jcs5100276
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 277: Using Graphene Nanoplatelets Nanofluid
           in a Closed-Loop Evacuated Tube Solar Collector—Energy and Exergy
           Analysis

    • Authors: Soudeh Iranmanesh, Mahyar Silakhori, Mohammad S. Naghavi, Bee C. Ang, Hwai C. Ong, Alireza Esmaeilzadeh
      First page: 277
      Abstract: Recently, nanofluid application as a heat transfer fluid for a closed-loop solar heat collector is receiving great attention among the scientific community due to better performance. The performance of solar systems can be assessed effectively with the exergy method. The present study deals with the thermodynamic performance of the second law analysis using graphene nanoplatelets nanofluids. Second law analysis is the main tool for explaining the exergy output of thermodynamic and energy systems. The performance of the closed-loop system in terms of energy and exergy was determined by analyzing the outcome of field tests in tropical weather conditions. Moreover, three parameters of entropy generation, pumping power and Bejan number were also determined. The flowrates of 0.5, 1 and 1.5 L/min and GNP mass percentage of 0.025, 0.5, 0.075 and 0.1 wt% were used for these tests. The results showed that in a flow rate of 1.5 L/min and a concentration of 0.1 wt%, exergy and thermal efficiencies were increased to about 85.5 and 90.7%, respectively. It also found that entropy generation reduced when increasing the nanofluid concentration. The Bejan number surges up when increasing the concentration, while this number decreases with the enhancement of the volumetric flow rate. The pumping power of the nanofluid-operated system for a 0.1 wt% particle concentration at 0.5 L/min indicated 5.8% more than when pure water was used as the heat transfer fluid. Finally, this investigation reveals the perfect conditions that operate closest to the reversible limit and helps the system make the best improvement.
      Citation: Journal of Composites Science
      PubDate: 2021-10-15
      DOI: 10.3390/jcs5100277
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 278: Calcium-Based Biomineralization: A
           Smart Approach for the Design of Novel Multifunctional Hybrid Materials

    • Authors: Elisabetta Campodoni, Margherita Montanari, Chiara Artusi, Giada Bassi, Franco Furlani, Monica Montesi, Silvia Panseri, Monica Sandri, Anna Tampieri
      First page: 278
      Abstract: Biomineralization consists of a complex cascade of phenomena generating hybrid nano-structured materials based on organic (e.g., polymer) and inorganic (e.g., hydroxyapatite) components. Biomineralization is a biomimetic process useful to produce highly biomimetic and biocompatible materials resembling natural hard tissues such as bones and teeth. In detail, biomimetic materials, composed of hydroxyapatite nanoparticles (HA) nucleated on an organic matrix, show extremely versatile chemical compositions and physical properties, which can be controlled to address specific challenges. Indeed, different parameters, including (i) the partial substitution of mimetic doping ions within the HA lattice, (ii) the use of different organic matrices, and (iii) the choice of cross-linking processes, can be finely tuned. In the present review, we mainly focused on calcium biomineralization. Besides regenerative medicine, these multifunctional materials have been largely exploited for other applications including 3D printable materials and in vitro three-dimensional (3D) models for cancer studies and for drug testing. Additionally, biomineralized multifunctional nano-particles can be involved in applications ranging from nanomedicine as fully bioresorbable drug delivery systems to the development of innovative and eco-sustainable UV physical filters for skin protection from solar radiations.
      Citation: Journal of Composites Science
      PubDate: 2021-10-15
      DOI: 10.3390/jcs5100278
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 279: Effect of Hybrid Fibres on the
           Durability Characteristics of Ternary Blend Geopolymer Concrete

    • Authors: V. Sathish Kumar, N. Ganesan, P. V. Indira
      First page: 279
      Abstract: The need to develop sustainable concrete in the civil infrastructure industry increases day by day, resulting in new eco-friendly materials such as geopolymer concrete. Geopolymer concrete is one of the eminent alternatives to conventional concrete for sustainable development by reducing the carbon footprint. Ternary blend geopolymer concrete (TGPC) is a sustainable and environmentally friendly concrete produced with three different source materials to form a binder. The main advantage of TGPC is that it possesses densely packed particles of different shapes and sizes, which results in improved properties. This paper deals with the experimental investigations to evaluate the durability properties of plain and hybrid fibre reinforced TGPC. The durability of concrete is defined as the ability to withstand a safe level of serviceability and different environmental exposure conditions without any significant repair and rehabilitation throughout the service life. Conventional concrete is vulnerable to cracking due to its low tensile and durability properties. The TGPC considered in this work consists of fly ash, GGBS and metakaolin as source materials, selected mainly based on the material’s silica and alumina content, shape, size, and availability. The grade of concrete considered was M55. The main variables considered in this study were the proportions of crimped steel fibres (Vf), viz., 0.5% and 1% and proportions of polypropylene fibres (Vp)viz., 0.1%, 0.15%, 0.20% and 0.25%. The durability properties like water absorption, sorptivity, resistance to marine attack, acid attack, sulphate attack, and abrasion were studied in this investigation. The experimental test results were compared with the requirements provided in the standard/literature and found to be well within limits. The study also indicates that the inclusion of fibres in a hybrid form significantly improves the durability parameters of TGPC. The TGPC with 1% steel fibre and 0.15% polypropylene fibre performs better than the other combination of fibres considered in this experimental investigation.
      Citation: Journal of Composites Science
      PubDate: 2021-10-15
      DOI: 10.3390/jcs5100279
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 280: Influence of Heat Treatment on the
           Corrosion Behaviour of Aluminium Silver Nano Particle/Calcium Carbonate
           Composite

    • Authors: Omolayo Michael Ikumapayi, Esther T. Akinlabi, Olayinka Oluwatosin Abegunde, Precious Ken-Ezihuo, Henry A. Benjamin, Sunday Adeniran Afolalu, Stephen A. Akinlabi
      First page: 280
      Abstract: Corrosion is one of the leading sources of material failure and deterioration in society. Scholars have proposed different techniques to mitigate corrosion. This research study explores and validates one of these techniques. An Aluminium metal matrix (AMC) was produced using the stir casting method with various weight percentages of AgNp and CaCO3 reinforcements. Heat treatment was performed on the samples to enhance the metallurgical and corrosion properties of the materials. The corrosion rate of the AMC samples was tested in different corrosive media (neutral and acidic) with different concentrations using the weight loss analysis technique for several days. It was observed that the corrosion rate of the AMC relies on the nature of the electrolyte and the percentage concentration of this electrolyte. The heat treatment improves the corrosion resistance of the AMC samples. In addition, an increase in the % weight composition of the reinforcement (AgNp + CaCO3) results in a reduction in the corrosion rate of the AMC in both corrosive media. The optimal %weight composition was found to be 4% for the hybrid reinforcement of AgNp + CaCO3 and 6% for the CaCO3 reinforcement in both the untreated and heat-treated samples.
      Citation: Journal of Composites Science
      PubDate: 2021-10-16
      DOI: 10.3390/jcs5100280
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 281: Mechanically Stable β-TCP Structural
           Hybrid Scaffolds for Potential Bone Replacement

    • Authors: Matthias Ahlhelm, Sergio H. Latorre, Hermann O. Mayr, Christiane Storch, Christian Freytag, David Werner, Eric Schwarzer-Fischer, Michael Seidenstücker
      First page: 281
      Abstract: The authors report on the manufacturing of mechanically stable β-tricalcium phosphate (β-TCP) structural hybrid scaffolds via the combination of additive manufacturing (CerAM VPP) and Freeze Foaming for engineering a potential bone replacement. In the first step, load bearing support structures were designed via FE simulation and 3D printed by CerAM VPP. In the second step, structures were foamed-in with a porous and degradable calcium phosphate (CaP) ceramic that mimics porous spongiosa. For this purpose, Fraunhofer IKTS used a process known as Freeze Foaming, which allows the foaming of any powdery material and the foaming-in into near-net-shape structures. Using a joint heat treatment, both structural components fused to form a structural hybrid. This bone construct had a 25-fold increased compressive strength compared to the pure CaP Freeze Foam and excellent biocompatibility with human osteoblastic MG-63 cells when compared to a bone grafting Curasan material for benchmark.
      Citation: Journal of Composites Science
      PubDate: 2021-10-17
      DOI: 10.3390/jcs5100281
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 282: Flexural Property of a Composite
           Biomaterial in Three Applications

    • Authors: Masao Irie, Yukinori Maruo, Goro Nishigawa, Takuya Matsumoto
      First page: 282
      Abstract: Resin composite is widely used in the dental field in clinics as a biomaterial. For example, it has been used as a composite material, a type of biomaterial, to repair caries and restore masticatory function, and as a luting agent to adhere the restoration to the tooth substrate. In order to demonstrate its function, we have measured the mechanical strength. From such basic research, we explain the potential of a dental material through the measurement of flexural strength and modulus of elasticity. In this research, we introduce commercial products that are actually used as composite materials suitable for tooth substrate and provide readers with their properties based on flexural strength and modulus of elasticity. In clinical performance, it might be advisable to delay polishing when a composite material is used for a luting material, a filling material and a core build-up material, as the flexural strength and the flexural modulus of elasticity were improved after 1 day of storage, and flexural strength and characteristics are considered as important mechanical properties of oral biomaterials.
      Citation: Journal of Composites Science
      PubDate: 2021-10-18
      DOI: 10.3390/jcs5100282
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 283: Recent Advances in Strain-Hardening
           UHPC with Synthetic Fibers

    • Authors: Jian-Guo Dai, Bo-Tao Huang, Surendra P. Shah
      First page: 283
      Abstract: This paper summarizes recent advances in strain-hardening ultra-high-performance concretes (UHPC) with synthetic fibers, with emphasis on their tensile properties. The composites described here usually contain about 2.0% high-density polyethylene (PE) fibers. Compared to UHPC with steel fibers, strain-hardening UHPC with synthetic fibers generally show a higher tensile ductility, lower modulus in the cracked state, and relatively lower compressive strength. The tensile strain capacity of strain-hardening UHPC with synthetic fibers increases with increasing tensile strength. The f’cftεt/w index (compressive strength × tensile strength × tensile strain capacity/tensile crack width) is used to compare the overall performance of strain-hardening UHPC. Moreover, a probabilistic approach is applied to model the crack width distributions of strain-hardening UHPC, and estimate the critical tensile strain in practical applications, given a specific crack width limit and cumulative probability. Recent development on strain-hardening UHPC with the use of seawater, sea-sand and PE fibers are also presented.
      Citation: Journal of Composites Science
      PubDate: 2021-10-18
      DOI: 10.3390/jcs5100283
      Issue No: Vol. 5, No. 10 (2021)
       
  • J. Compos. Sci., Vol. 5, Pages 284: The Factors That Affect the Expansion
           of the Tape for It to Avoid Side Effects in the Production of Composites
           in Online LATP Technology

    • Authors: Svetlana Risteska, Samoil Samak, Vele Samak
      First page: 284
      Abstract: During LATP (laser automated tape placement), the compaction roller contacts the prepreg and affects the pressure distribution directly. Moreover, the design parameters of the roller are optimized with the aim of improving pressure uniformity. This paper examines the impact of the contact line and surface that depends on the compaction force, the design of the roller, the angle of inclination and the angle of inclination of the strip. These factors significantly affect the expansion of the tape, and it is important to determine it to avoid side effects in the production of composites (formation of gaps or overlaps). Their presence increases the percentage of pores of the final material and thus reduces the mechanical properties. The results show that the pressure uniformity can be improved significantly by design optimization of the roller, which indicates that higher bond quality between layers is achieved. The lower the speed and higher the compact force in this technology give better intimate contact with a lower percentage of voids and good mechanical characteristics.
      Citation: Journal of Composites Science
      PubDate: 2021-10-19
      DOI: 10.3390/jcs5100284
      Issue No: Vol. 5, No. 10 (2021)
       
 
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