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  Subjects -> ENGINEERING (Total: 2270 journals)
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ENGINEERING (1199 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Full-text available via subscription   (Followers: 5)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 216)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 4)
Advanced Science     Open Access   (Followers: 4)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
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Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
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Advances in Fuzzy Systems     Open Access   (Followers: 5)
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Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
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Advances in Remote Sensing     Open Access   (Followers: 35)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 28)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 27)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 8)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 7)
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Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
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Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 2)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 7)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
Batteries     Open Access   (Followers: 3)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 9)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 3)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 38)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Full-text available via subscription   (Followers: 13)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 40)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Thermal Engineering     Open Access   (Followers: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 9)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 4)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
Coatings     Open Access   (Followers: 2)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 23)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 252)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 177)
Composites Part B : Engineering     Hybrid Journal   (Followers: 222)
Composites Science and Technology     Hybrid Journal   (Followers: 165)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
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Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 41)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 24)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  

        1 2 3 4 5 6 | Last

Journal Cover Composites Science and Technology
  [SJR: 1.512]   [H-I: 144]   [165 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0266-3538
   Published by Elsevier Homepage  [3031 journals]
  • Interfacial layer thickness design for exploiting the reinforcement
           potential of nanocellulose in cellulose triacetate matrix
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Hiroto Soeta, Shuji Fujisawa, Tsuguyuki Saito, Akira Isogai
      The contribution of the interfacial layer thickness to composite properties was investigated using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofiber (TOCN) and cellulose triacetate (CTA). To control the interfacial layer thickness, the surface of the TOCNs was modified by grafting amine-terminated poly(ethylene glycol) (PEG-NH2) with different molecular weights. Neat TOCNs or PEG-grafted TOCNs were compounded with CTA to prepare nanocomposite films with different interfacial layer thicknesses. We demonstrated that thinner interfacial layers enhanced the stiffness of the nanocomposite films, whereas thicker interfacial layers enhanced their ductility. The high transparency and low birefringence of the CTA films were preserved even with the addition of TOCNs or PEG-grafted TOCNs. Although the thermal expansion of the nanocomposite films was suppressed by TOCN addition, the presence of PEG layers on the TOCN surfaces had a negative impact on their restraint of the thermal expansion. These results suggest that the interfacial layer thickness plays an important role in the mechanical and thermal properties of nanocellulose-reinforced composites.
      Graphical abstract image

      PubDate: 2017-05-18T07:16:16Z
       
  • Unique liquid-to-solid transition of carbon filler filled polystyrene
           melts
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Yihu Song, Lingbin Zeng, Qiang Zheng
      Nanoparticle reinforcement beyond the hydrodynamics regime has been predominantly assigned to filler networking effect. Herein a unique hydrodynamics-to-nonhydrodynamics transition has been disclosed by creating master curves of relative dynamic modulus as a function of scaled frequency. Such conclusion is drawn for polystyrene filled with four different carbon fillers, i.e., carbon black, fullerene, multi-walled carbon nanotubes and graphite nanoplatelets. Additional rheological contribution of the filler phase beyond the hydrodynamics regime disclosed is sensitive to the filler type. The study may provide guidance for fundamental researches on the simultaneous reinforcement and dissipation of composites varying with filler topology.

      PubDate: 2017-05-13T01:34:59Z
       
  • Significantly improved dielectric properties and energy density of polymer
           nanocomposites via small loaded of BaTiO3 nanotubes
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Zhongbin Pan, Lingmin Yao, Jiwei Zhai, Bo Shen, Haitao Wang
      Flexible dielectric polymeric films are highly desirable materials with potential applications in power-conditioning equipment and pulsed-plasma thrusters due to their high dielectric constant, low dielectric loss, and fast energy uptake and delivery. In this work, 1–3 type nanocomposites combining BaTiO3 nanotubes (BT NTs) and poly(vinylidene fluoride) (PVDF) were prepared by a solution cast method. The BT NTs were synthesized by facile coaxial electrospinning and were coated with a dense and robust dopamine layer, which effectively improved the filler-matrix distributional homogeneity and compatibility. The 10.8 vol% BT-DA NTs/PVDF nanocomposites possessed an excellent dielectric constant of 47.05, which is approximately 569% greater that of the pristine PVDF (8.26) and 150%–350% higher than that of the other PVDF nanocomposites loaded with similar ceramic filler contents, e.g., nanoparticles, nanowires, and nanofibers. The highest energy density of 7.03 J cm−3 at a relatively low field of 330 MV m-1 was obtained via small loaded of the fillers, which is approximately 625% greater than for biaxially oriented polypropylenes (BOPP) (1.2 J cm−3 at the field of 640 MV m−1). The approach employed in this study may be further applied to the fabrication of similar polymeric nanocomposites for next-generation electronic components.

      PubDate: 2017-05-13T01:34:59Z
       
  • Flexible, elastic, and superhydrophobic silica-polymer composite aerogels
           by high internal phase emulsion process
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Dinesh B. Mahadik, Hae-Noo-Ree Jung, Wooje Han, Hyung Hee Cho, Hyung-Ho Park
      Flexible, elastic, low density, superhydrophobic, and low thermal conductive silica-polymer composite aerogel materials were prepared by a high internal phase emulsion (HIPE) process followed with sol-gel process. Flexible silica aerogels were grown in the scaffold of macro-porous flexible polymer monolith to overcome the brittle nature of silica aerogels. Initially, porous polymer monolith was prepared by HIPE and was used as a scaffold for preparation of flexible silica aerogels by sol-gel process followed by supercritical drying. Polymer monolith was soaked in a pre-hydrolyzed methyltrimethoxysilane (MTMS) based silica sol and gelation was achieved by two step sol-gel process. Composite monolith possess extreme properties such as high flexibility, elasticity, superhydrophobicity (165°), low density (0.045 g/cm3) and thermal conductivity (0.040 W/m·K). This novel way of preparation allows us to overcome the fragile nature of MTMS based flexible silica aerogels while maintaining textural, physical, and functional properties. Hence such materials are highly useful for corrosion resistant thermal insulation in various fields.

      PubDate: 2017-05-13T01:34:59Z
       
  • Anisotropic thermal property of magnetically oriented carbon
           nanotube/graphene polymer composites
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Bin Li, Shuai Dong, Xuan Wu, Caiping Wang, Xiaojie Wang, Jun Fang
      A method was developed to magnetically align multi-walled carbon nanotubes (MWCNTs) as well as graphene nanoplates (GNPs) within a poly (dimethylsiloxane) (PDMS) matrix. The MWCNTs and GNPs polymer composites treated with magnetic field forming chain structures would be expected to produce anisotropic thermal conductivity. Firstly, the MWCNTs and GNPs were functionalized by γ-methacryloxy propyl trimethoxyl silane (KH570) in order to improve their compatibility with polymer matrix, and then different contents of the MWCNTs and GNPs were incorporated into PDMS and cured under a magnetic field up to 10 T to generate anisotropic MWCNTs/PDMS and GNPs/PDMS composites. The polarized Raman spectra and scanning electron microscopy (SEM) were applied to investigate the structures of MWCNTs and GNPs dispersion in the composites. The thermal conductivity of all samples was measured by using hot wire method. The results showed that the magnetically aligned MWCNTs/GNPs polymer composites feature high anisotropy in thermal conductivity. Thermal conductivity in the aligned direction of 10.0 T-treated PDMS composites with 3wt% GNPs content showed enhancements of 174% and 49%, compared to pure PDMS and non-magnetically treated GNP/PDMS composites, respectively. Compared with the MWCNTs fillers, the GNPs showed better performance in improvement of the thermal conductivity of the polymer composites.

      PubDate: 2017-05-13T01:34:59Z
       
  • Multifunctional structural lithium ion batteries based on carbon fiber
           reinforced plastic composites
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Yalin Yu, Boming Zhang, Mengjie Feng, Guocheng Qi, Fangyu Tian, Qihang Feng, Jiping Yang, Shubin Wang
      In this study, the feasibility of multifunctional structural lithium ion batteries (LIBs) based on carbon fiber reinforced plastic (CFRP) composites was investigated. T700S carbon fabrics undertook the roles of both reinforcements and electrode materials in structural batteries. The co-continuous structural electrolytes were prepared by in-situ cure of liquid electrolyte and epoxy resin with the abilities of both load bearing and lithium ion transport. The structural electrolytes were cured with the carbon fabrics to process the CFRP composites. With the increase of liquid electrolyte/epoxy mass ratio, a trade-off relationship was found between the mechanical performance and electrochemical properties of both the structural electrolytes and the corresponding CFRP composites. The CFRP composites based on liquid/epoxy structural electrolytes were proved to have the ability to insert and extract lithium, and can be considered as the potential candidate for the multifunctional structural LIBs. The strategy of functionalizing the LIBs with structural performance via CFRP composites could be helpful for the overall system to provide a mass reduction as well as increase the energy efficiency at a system-level.

      PubDate: 2017-05-13T01:34:59Z
       
  • Mechanical and electrical properties of ethylene-1-octene and
           polypropylene composites filled with carbon nanotubes
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): I. Burmistrov, N. Gorshkov, I. Ilinykh, D. Muratov, E. Kolesnikov, E. Yakovlev, I. Mazov, J.-P. Issi, D. Kuznetsov
      In the present work, the effect of carbon nanotubes (CNTs) addition on the electrical conductivity and mechanical properties of thermoplastic polymers was investigated. CNTs were incorporated into the polymer matrix either in high concentrations (masterbatch) or as an additive in small quantity (dilution source of masterbatches in a polymeric binder). Masterbatches containing a 5–20% by weight of CNTs and composites obtained through their addition in polypropylene - the actual content of CNTs in polymer 0.1 and 0.01 wt% - were synthesized and characterized by mechanical tests and scanning electron microscopy. Also, the frequency dependence of the AC electrical conductivity of masterbatches and dilute composites were measured. It has been shown that the introduction of masterbatches containing 10 wt% of CNT provides a more efficient reinforcement of the composite than those using masterbatches with 5 and 20 wt% of CNTs. It is also found that the alternating current (AC) conductivities display two or three regions: regions of constant conductivity and regions where the conductivity increases with increasing frequency (following the percolation scaling law). It was also observed that the conductivity increases drastically with increasing CNT content in the investigated concentration range (from 0 to 20 wt%).

      PubDate: 2017-05-13T01:34:59Z
       
  • Core-shell rubber nanoparticle reinforcement and processing of high
           toughness fast-curing epoxy composites
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): A. Keller, H.M. Chong, A.C. Taylor, C. Dransfeld, K. Masania
      To simultaneously address the lower toughness and the build-up of internal heat for fast-curing epoxy matrices, the influence of nominal 100 nm and 300 nm core-shell rubber (CSR) particles on the properties and rheo-kinetics were studied. The fracture energy was enhanced by a factor of 14.5, up to 2572 ± 84 J m−2 with 14.5 wt% of the nominal 300 nm diameter CSR particles, with evidence of cavitation and plastic void growth of the rubber core combined with shear band yielding of the epoxy matrix. These toughening mechanisms were modelled with an approximately linear increase up to 10 wt% for both particle types. At higher concentrations, deviation between the measured and modelled data was observed due to insufficient epoxy to dissipate additional energy. The CSR particles were not filtered out or damaged during the manufacturing of composites and reduced the total heat of reaction with a linear correlation, demonstrating a multi-functionality of simultaneous toughening and reduction of the exothermic peak.

      PubDate: 2017-05-13T01:34:59Z
       
  • Influence of manufacturing defects on modal properties of composite
           pyramidal truss-like core sandwich cylindrical panels
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Jin-Shui Yang, Li Ma, Mauricio Chaves-Vargas, Tian-Xiang Huang, Kai-Uwe Schröder, Rüdiger Schmidt, Lin-Zhi Wu
      Defects can easily appear in composite lattice truss core sandwich structures during the complex preparation process, which may significantly affect the structural response and decrease the load-carrying capability. The purpose of this paper is to investigate the manufacturing defect sensitivity of modal vibration responses of carbon fiber composite pyramidal truss-like core sandwich cylindrical panels by modal experiments and finite element analysis. Defects including debonding between face sheets and truss cores (DFT), truss missing (DTM), face sheet wrinkling (DFW) and gap reinforcing (DGR) are introduced into the present intact specimen artificially and modal testing is conducted to study their dynamic behavior under free-free boundary conditions. Finite element models consistent with the experiments are then developed to further study the effect of defect extents, locations and forms on the modal parameters of the present sandwich cylindrical panels. Results indicate that the degree of sensitivity of natural frequencies of the present sandwich cylindrical panels mainly depends on the vibration modes, defect extents, locations and forms. In addition, damping loss factors are much more sensitive than their corresponding frequencies. Some conclusions and essential mechanisms are summarized, which is helpful to vibration-based non-destructive evaluation (NDE) of such kind of composite lattice sandwich structures.

      PubDate: 2017-05-13T01:34:59Z
       
  • A computationally-efficient hierarchical scaling law to predict damage
           accumulation in composite fibre-bundles
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Soraia Pimenta
      Unidirectional composites under longitudinal tension develop damage through the accumulation and clustering of fibre–breaks, which may lead to catastrophic failure of an entire structure. This paper uses a hierarchical scaling law to predict the kinetics of fibre–breakage and its effect on the stress–strain response of composites under longitudinal tension; due to its analytical formulation based on the statistical analysis of hierarchical fibre–bundles, the scaling law predicts the response of composite bundles up to virtually any size in less than one second. Model predictions for the accumulation and clustering of fibre–breaks are successfully validated against experiments from the literature. These results show that the present model is a much more computationally–efficient alternative to other state–of–the–art models based on Monte–Carlo simulations, without sacrificing the accuracy of predictions when compared against experiments.

      PubDate: 2017-05-13T01:34:59Z
       
  • Rational design of adhesion promoter for organic/inorganic composites
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Yong Ding, Zongzhi Yu, Junping Zheng
      Weak interfacial interaction between organic matrix and inorganic particles poses immense challenges for the application of organic/inorganic composites in science and technology. This article systematically studied the influence of adhesion promoters' structure on interfacial properties of organic/inorganic nanocomposites. The structure of adhesion promoters was designed to differ in polymerizable group, charged group and chain length. Silica and polymethyl methacrylate were selected as inorganic nanoparticles and organic matrix, respectively. Our study shows adhesion promoter with charged group, polymerizable group as well as hexyl chain has the best ability to improve the interfacial adhesion of organic/inorganic nanocomposites. This study provides a new insight into choosing adhesion promoters for organic/inorganic nanocomposites with desired interfacial properties.

      PubDate: 2017-05-08T08:33:02Z
       
  • Development of PLA/Mg composite for orthopedic implant: Tunable
           degradation and enhanced mineralization
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Changli Zhao, Hongliu Wu, Jiahua Ni, Shaoxiang Zhang, Xiaonong Zhang
      Polylactic acid (PLA) orthopedic devices suffer from low degradation rate and inadequate osteoconductivity, and often lose efficacy in the late stage of implantation because of inflammatory response of acid products and inability integration to bone. In this work, 2 wt% and 5 wt% magnesium particles reinforced PLA were fabricated using solvent casting and investigated in terms of in vitro degradation and biomineralization. The uniformly distributed Mg particles slightly decreased the crystallinity of PLA. The pH value and variations in mass analysis during the in vitro degradation showed that the Mg incorporation could effectively neutralize the acidic products of PLA, as well as induce more apatite deposition. Great decrease in molecular weight of 2 wt% and 5 wt% Mg/PLA composites as compared to the neat PLA after 8 weeks' immersion made it possible to modulate the degradation rate of the PLA by controlling the proportion of Mg content and other key factors such as size and shape of the Mg reinforcements. In vitro cell culture revealed good biocompatibility of Mg/PLA, and the favorable characteristic for osteoblastic cells to adhere and spread. The cellular biomineralization results demonstrated significantly higher bone-like nodules deposition (both in number and area) achieved on the composite surfaces than that on PLA surface after 14 and 28 days culture. The promoting bone-forming ability derives from the degradation of Mg particles. The study elucidated the positive effects of Mg incorporated to PLA matrix on the degradation and osteogenesis, and provide an alternative for the currently used PLA implants.

      PubDate: 2017-05-08T08:33:02Z
       
  • Influence of nitrodopamine-functionalized barium titanate content on the
           piezoelectric response of poly(vinylidene fluoride) based polymer-ceramic
           composites
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Juliette Defebvin, Sophie Barrau, Joël Lyskawa, Patrice Woisel, Jean-Marc Lefebvre
      Piezocomposites were elaborated by incorporating barium titanate (BT) ceramic particles into a poly(vinylidene fluoride) (PVDF) matrix. A key issue of the process is to obtain the electroactive β crystal phase in PVDF by stretching the polymer-ceramic composite. For this purpose, as well as in view of enabling the poling step of the composite film, the interfacial cohesion between ceramic and polymer has to be efficient and this has been achieved by nitrodopamine functionalization of the ceramic surface (nBT). The structural evolution associated to the deformation-induced α-β crystal phase transformation in the presence of nBT has been analyzed in situ under stretching. The piezoelectric properties of these composites have been characterized in parallel poling. In the range of nBT filler loading under investigation, it is shown that the d33 piezoelectric coefficient of the composite is modulated by the ceramic content. Polymer matrix dominated response yields a negative d33 value at low nBT content. Interestingly enough, the piezoelectric response is null at 26 wt% nBT loading and the piezoelectric coefficient becomes positive beyond that filler fraction.

      PubDate: 2017-05-08T08:33:02Z
       
  • A novel laminate analogy to calculate the strength of two-dimensional
           randomly oriented short-fiber composites
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): M.M. Shokrieh, H. Moshrefzadeh-Sani
      In this paper, a new laminate analogy for progressive damage modeling of two-dimensional randomly oriented short-fiber composites is developed. In the present model, two-dimensional randomly oriented short-fiber composite is replaced by an equivalent laminated composite, which contain several unidirectional layers oriented between 0° to 180°. An incremental algorithm is presented to simulate the stress-strain behavior of composites up to the final failure. In the first step, using the shear-lag theory and the Halpin-Tsai method, the on-axis stiffness and strength of each layer were calculated. Then, using the Tsai-Wu failure criterion, damaged layers were detected and the residual moduli of damaged layers were calculated by a random based approach. After failure of each layer, undamaged layers must sustain more stresses. Therefore, the continuum damage mechanics was used to calculate the effective stress in each load increment. A comparison of results of the present model with experimental data available in the literature shows the capability of the model.

      PubDate: 2017-05-08T08:33:02Z
       
  • Fabrication of injectable and expandable PMMA/PAASf bone cements
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Yufei Tang, Lei Chen, Zixiang Wu, Kang Zhao, Quanchang Tan
      The volume of polymethyl methacrylate (PMMA) bone cement shrank by 3.82%–7.08% during solidification. Such volume shrinkage generated a residual stress that induces minor cracking in bone–cement interface and affected the long-term stability and mechanical property of vertebral body. In this study, injectable and expandable PMMA/sodium polyacrylate short fiber (PAASf) composite bone cements were fabricated, and water absorption and swelling properties of PAASf were taken into account. Effects of PAASf volume fraction in PMMA/PAASf bone cements on absorption ratios of simulated body fluid (SBF) and volume expansion ratios were investigated. When the volume fraction of PAASf was lower than 30%, PMMA/PAASf bone cements were stable and did not fall apart after expansion in SBF, and the maximum volume expansion ratio was 33.4%. When PAASf content increased from 10 vol% to 30 vol%, solidification time of PMMA/PAASf bone cements increased and their injection and mechanical properties decreased, although the PMMA/PAASf bone cements (9:1) still satisfy the requirements for clinical application. The absorption expansion mechanism of PMMA/PAASf bone cements in SBF in the first stage of expansion (global expansion before solidification) and in the second stage of expansion (local surface expansion after solidification) was analyzed through micro-computed tomography and SEM. Cytotoxicity of PMMA bone cement and PMMA/PAASf bone cements were compared, and results suggested that their cytotoxicity did not significantly vary. These findings indicated that injectable and expandable PMMA/PAASf bone cements can be used in clinical treatments.

      PubDate: 2017-05-08T08:33:02Z
       
  • Enhancement of dielectric and electrical properties in BFN/Ni/PVDF
           three-phase composites
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Zhuo Wang, Tian Wang, Mingrui Fang, Chun Wang, Yujia Xiao, Yongping Pu
      To develop dielectric materials with high dielectric constant and low dielectric loss, a novel three-phase composite was prepared by embedding the nano-sized Ba(Fe0.5Nb0.5)O3 (BFN) crystallites and Ni crystallites into poly(vinylidene fluoride) (PVDF) matrix. The structure, dielectric and electrical properties of the composites were investigated. The superiority of this method is that, when compared with the two-phase Ni/PVDF composites, three-phase composites not only show significantly increased dielectric constants but also have lower dielectric loss. Our results show that a high dielectric constant of 475 and a relatively low loss of 0.61 were achieved at 100 Hz with 25 vol.% Ni and 50 vol.% BFN, respectively. The enhancement of dielectric constant of polymer based composites can be interpreted by the mini-capacitor principle and the interfacial polarization. The relatively low dielectric loss could be attributed to the isolation effect of BFN fillers. These composites with high dielectric constant and low dielectric loss are found to be potentially useful for embedded capacitor applications.

      PubDate: 2017-05-02T09:33:12Z
       
  • Effect of MWCNTs-GO hybrids on tribological performance of hybrid
           PTFE/Nomex fabric/phenolic composite
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Guina Ren, Zhaozhu Zhang, Yuanming Song, Xiangming Li, Jingyong Yan, Yuyan Wang, Xiaotao Zhu
      Filler reinforcing is an effective way of improving the tribological performance of fabric composites. However, the interface stability between fillers and the polymer matrix is critical for filler reinforced composites. To address this problem, hybrids of MWCNTs and graphene oxide (GO) are developed to improve the mechanical and tribological performances of hybrid PTFE/Nomex fabric/phenolic composite. Pin-on-disk wear tests show that the wear rates of hybrid fillers filled fabric/phenolic composites are significantly reduced, when hybrid filler of 1 wt% MWCNTs and 2 wt% GO is employed. We also investigated the effect of filler content on the mechanical and tribological property of the fabric composites. The wear mechanisms of the composites are discussed based on the characterizations.

      PubDate: 2017-05-02T09:33:12Z
       
  • Influence of filler surface characteristics on morphological, physical,
           acoustic properties of polyurethane composite foams filled with inorganic
           fillers
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Giwook Sung, Jung Hyeun Kim
      In modern automobiles, noise pollution is a critical issue, and polyurethane foam is commonly used due to its high sound absorption and ease of production. In this study, polyurethane composite foams were fabricated using inorganic fillers (Talc, Zinc Borate, and Aluminum Hydroxide), and the morphological and physical properties were assessed. The cavity and pore sizes of composite foams with hydrophobic fillers were smaller than those of foams with hydrophilic fillers due to differences in the cell collapsing phenomena. This difference in the surface properties of the filler also significantly affects the physical strength of the composite materials, and it is further related to the sound absorption efficiency of the foams. This sound absorption coefficient revealed the same trend with the loss modulus reflecting a measure of the dissipated energy between the polymer chains and fillers through microstructural deformations.

      PubDate: 2017-05-02T09:33:12Z
       
  • Preparation of epoxy nanocomposites containing well-dispersed graphene
           nanosheets
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Haiqing Yao, Spencer A. Hawkins, Hung-Jue Sue
      To take full advantage of the potential of graphene nanosheets as reinforcing agents for polymer nanocomposites, good exfoliation, homogenous dispersion, and strong affinity of graphene nanosheets in a polymer matrix are needed. In this research, homogeneous dispersion of graphene nanosheets in epoxy is achieved via chemical functionalization of graphene oxide with 4-nitrobenzenediazonium salt. Optical microscopy and transmission electron microscopy demonstrate that graphene nanosheets are well-exfoliated in organic solvents and in epoxy. While only a marginal increase in Young's modulus is observed, significant improvements in tensile strength (>30%) and elongation at break (>50%) for epoxy nanocomposites with a graphene concentration of 0.8 wt.% are achieved. The thermal conductivity of an epoxy nanocomposite with modified graphene nanosheets at 5 wt.% increases to 0.56 W/mK, approximately 2.5 times that of the neat epoxy. The possible mechanisms that account for the observed improvements in tensile properties and thermal conductivity are discussed.

      PubDate: 2017-05-02T09:33:12Z
       
  • Highly electrically conductive and stretchable copper nanowires-based
           composite for flexible and printable electronics
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Wangping Huang, Jinhui Li, Songfang Zhao, Fei Han, Guoping Zhang, Rong Sun, Ching-Ping Wong
      Copper nanowires (CuNWs) have been considered for the promising application as conductive element of stretchable conductors due to ultrahigh aspect ratio, outstanding conductivity, great flexibility and low-cost. However, controllable synthesis, surface oxidation, poor dispersity have always been main limitations to their application in stretchable conductors. Herein, highly conductive, stretchable and fully printable CuNWs-based composites (PNCNs) by infiltrating CuNWs into poly(styrene-blockbutadiene-block-styrene) (SBS) with a facile, cost-effective and scalable method were reported. CuNWs of high quality, chemical treatment by vacuum filtration way and special dispersion method facilitate fabrication of PNCNs of high performance. As-prepared PNCNs have superior electrical conductivity of 1858 S cm−1, high break elongation of 920%. Moreover, PNCNs are stable after 1000 cycles for a bend radius of 4.0 mm and electric performance was not affected by twisting. Importantly, PNCNs can be printed on paper to fabricate flexible circuits which exhibit excellent electric performance at different tension conditions.

      PubDate: 2017-05-02T09:33:12Z
       
  • The GaNMn3-Epoxy composites with tunable coefficient of thermal expansion
           and good dielectric performance
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Jianchao Lin, Peng Tong, Kui Zhang, Xiaohang Ma, Haiyun Tong, Xinge Guo, Cheng Yang, Ying Wu, Meng Wang, Shuai Lin, Wenhai Song, Yuping Sun
      GaNMn3/Epoxy composites were prepared by using negative thermal expansion GaNMn3 powders as the metallic filler. By increasing the loading level of GaNMn3 powders, the hardness and heat conductivity were improved comparing with that of neat epoxy. When the loading level lies in 42 vol.% - 58 vol.% for GaNMn3-0.7 μm and 26 vol.% - 43 vol.% for GaNMn3-2.3 μm, the composites present low thermal expansion (the absolute value of linear thermal coefficient is less than 10 ppm/K), weak dielectric loss (less than 0.04), and the dielectric constants exceed 25, exhibiting great potential for applications in embedded-capacitor fields.

      PubDate: 2017-05-02T09:33:12Z
       
  • High-performance green nanocomposites using aligned bacterial cellulose
           and soy protein
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Muhammad M. Rahman, Anil N. Netravali
      Maximum potential of any fibers as reinforcing agent in composite materials can be obtained through their preferential alignment. In this study, a facile method has been developed to fabricate high-performance green composites based on aligned bacterial cellulose (BC) as reinforcing agent and soy protein as bio-resin. Aligned BC nanofibrils were produced by cultivating it inside polydimethylsiloxane (PDMS) tubes followed by an optimum wet-stretching. The curved geometry of the inner tube surface provided the bacteria a preferred direction for growth. Further improvement in alignment was obtained with optimized stretching of the tube-shaped BC (TBC) at a crosshead speed of 0.03 mm/min and draw ratio of 1.20. Stretched TBC showed superior mechanical properties in comparison to the conventionally-grown BC pellicle. Stretched TBC resulted in higher tensile strength (230% increase), modulus (330% increase), and orientation indices (135% increase) compared to the conventional BC pellicle. Soy protein isolate (SPI)-based fully green composites reinforced with TBC were prepared by a vacuum-assisted resin impregnation process, and the same stretching method was applied to the TBC-SPI gel. The stretched and cured composites showed significant improvements in the tensile strength (from 40 MPa to 150 MPa) and modulus (from 2 GPa to 8 GPa) in comparison to the conventional BC reinforced composite because of the enhanced alignment of BC nanofibrils.
      Graphical abstract image

      PubDate: 2017-05-02T09:33:12Z
       
  • High-performance rubber/boehmite nanoplatelets composites by judicious in
           situ interfacial design
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Chengfeng Zhang, Zhenghai Tang, Baochun Guo
      Interfacial interaction plays a vital role in the final properties of polymer composites as it affects the filler dispersion and stress transfer in the composites. In this study, we utilized two types of phosphate ester, hydroxyethyl methylacrylate phosphate (PH) and butyl phosphate (PB), as modifiers in boehmite (BM)-filled styrene-butadiene rubber (SBR) to tailor the interfacial structures in the composites. The modification mechanism of phosphate ester on BM and the interfacial structure in the composites are characterized. In PH-modified BM/SBR composites, a covalently bonding interface is obtained because PH can act as molecular bridge that can form covalent linkage with both BM and SBR chains. Consequently, the resulting composites show significantly improvements in the physical and mechanical properties of the composites. While in PB-modified BM/SBR composites, the properties of the composites are slightly improved due to the lack of covalent linkage in the interface.

      PubDate: 2017-05-02T09:33:12Z
       
  • Thermal conductivity of aerogel composites with oriented nitrogen-doped
           graphene
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Chenwu Yue, Jian Feng, Junzong Feng, Yonggang Jiang
      Aerogels with oriented sheets show better thermal insulation properties. However, it is difficult to prepare bulk oriented aerogels. In this paper, we prepared this kind of aerogels by using aligned fibers as the wall of galleries. This simple method makes the N-doped graphene sheets align along the in-plane orientation during impregnating. The as-prepared aerogel composites not only show much lower through-plane thermal conductivity (26.6–29.8 mW m−1 K−1) compared to their in-plane thermal conductivity (44.9–55.1 mW m−1 K−1), but also exhibit high tensile strength (higher than 3 MPa). After being heat treated at 300 °C, the through-plane thermal conductivity (23.3 mW m−1 K−1) is even lower than the thermal conductivity of pure aerogels. These properties significantly contribute to their applications in thermal insulation. Besides, the simple method is also useful in preparing other materials with oriented sheets and high strength.

      PubDate: 2017-05-02T09:33:12Z
       
  • Fracture behavior and crack sensing capability of bonded carbon fiber
           composite joints with carbon nanotube-based polymer adhesive layer under
           Mode I loading
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Tomo Takeda, Fumio Narita
      This paper presents a study on the Mode I fracture behavior and crack monitoring of bonded carbon fiber reinforced polymer (CFRP) composite joints with carbon nanotube (CNT)-based polymer adhesive layer. Bonded joints were fabricated using woven carbon/epoxy composite substrates and CNT-based epoxy adhesives. Mode I fracture tests were carried out with double cantilever beam (DCB) bonded joint specimens, and the dependence of the critical energy release rate at the onset of crack growth, i.e., fracture toughness, on the nanotube content in the adhesive layer and the adhesive layer thickness was examined. The electrical resistance of the bonded joint specimens was monitored during the tests. An analytical model based on the electrical conduction mechanism of CNT-based polymers was also employed to describe the electrical resistance change due to crack propagation in the bonded joint specimens, and a good correlation was obtained between the predicted and measured results. The electrical resistance change is found to result in quantitative assessment of crack length based on resistance measurement. It is demonstrated that the bonded CFRP composite joints with CNT-based polymer adhesive layer have improved fracture properties together with crack sensing capability.

      PubDate: 2017-04-25T17:47:48Z
       
  • Tunable morphology and hydrophilicity to epoxy resin from copper oxide
           nanoparticles
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Anu Tresa Sunny, Miran Mozetic, Gregor Primc, Suresh Mathew, Sabu Thomas
      Nanosized copper (I) oxide particles (nCOP) synthesized through chemical reduction reaction was employed to formulate an epoxy based novel nanocomposite material. Wetting characteristics of the nanocomposites were studied through contact angle measurements as a function of filler content. The contact angle of epoxy with water decreased from 79° to 35° when the filler content is varied from 0 to 10 phr indicating an upsurge in the hydrophilicity of the material. When the nCOP content is increased from 0 to 10phr, the surface free energy and work of adhesion endured a hike around 50% by magnitude, interfacial free energy suffered a decrease by half of its initial value, spreading coefficient became more positive while Girifalco-Good's interaction parameter changed by around 10%. The improvement in hydrophilicity of nanocomposite was attributed to the enrichment of the polymer surface with nanoparticles. The contact angle values of the nanocomposites were theoretically predicted using Li- Neumann- Young equation and compared with the experimental observations. The microstructure development in the nanocomposites was analyzed through plasma etching followed by electron microscopic imaging. Finally the tuning of the hydrophilicity of the epoxy resin in presence of varying nCOP content have been correlated with the morphology and microstructure development in the nanocomposites.

      PubDate: 2017-04-25T17:47:48Z
       
  • Crystallization derivation of amine functionalized T12 polyhedral
           oligomeric silsesquioxane-conjugated poly(ethylene terephthalate)
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Albert S. Lee, Hyeonyeol Jeon, Seung-Sock Choi, Jeyoung Park, Sung Yeon Hwang, Jonggeon Jegal, Dongyeop X. Oh, Byoung Chul Kim, Seung Sang Hwang
      Most inorganic nucleating agents for poly(ethylene terephthalate) (PET) have limited nucleating ability due to poor compatibility with PET. Polyhedral oligomeric silsesquioxanes (POSS) is a type of cage-shaped organic/inorganic hybrid nanoparticles with three different particle sizes: octameric (T8), decameric (T10), and dodecameric (T12). POSS is considered as a promising nucleating agent for PET because the inorganic moieties contribute to high thermal stability and nucleation and the organic moieties can be tethered to PET chains. In contrast to T8 POSS, the nucleation ability of T12 POSS for PET has been poorly reported. In this study, our newly synthesized aminopropyl functionalized T12 POSS (A-POSS) is proposed as a potential nucleating agent for PET. The amine group of A-POSS is able to be chemically conjugated to PET chains, thereby giving a more homogeneous dispersion of T12 POSS in PET than non-functional T12 Phenyl POSS (N-POSS). Its PET composites gave a ∼1.2 fold higher crystallization temperature and ∼2.7 fold higher shear-induced crystallization rate over pristine PET. Such nucleating effects for PET is more effective than those of non-functional T12 POSS and the more widely studied T8 POSS. This strategy is potentially beneficial for the high-shear melt processes of PET such as spinning and film extrusion.

      PubDate: 2017-04-25T17:47:48Z
       
  • Fatigue threshold-stress determination in AFP laminates containing gaps
           using IR thermography
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Yasser M. Elsherbini, Suong V. Hoa
      The existence of gaps during manufacturing using automated fiber placement (AFP) is unavoidable. It is of interest to determine the threshold stress value below which no effect of the gaps on fatigue life exists. This work aims to use infrared thermography and apply Risitano method on AFP laminates containing gaps to provide a quick method for obtaining the threshold value. This method has a great potential in saving time and material required for performing traditional fatigue tests to develop stress/life curves. Based on the thermal observations of surface temperature of gapped specimen under fatigue loading with different maximum stress levels, a relation between the thermal response and the applied stress was observed. From this relation, the threshold stress value can be evaluated using a small number of specimens and in a short time. To investigate the applicability of this technique to different stacking sequences, fatigue tests were conducted on unidirectional, four-angle and cross-ply laminates containing defects (gaps). In addition, stress/life curves were developed for reference and defected specimens in order to get the threshold value using the traditional (Wohler) method. The results of threshold stress using IR thermography are in very good agreement with the results obtained using the traditional way.

      PubDate: 2017-04-25T17:47:48Z
       
  • Graphene nanoplatelets coated glass fibre fabrics as strain sensors
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): R. Moriche, A. Jiménez-Suárez, M. Sánchez, S.G. Prolongo, A. Ureña
      The incorporation of graphene nanoplatelets (GNPs) as a coating on glass fibre fabrics for strain monitoring applications was analysed. Non-functionalized and functionalized GNPs were used in order to study the effect of the functionalization in the morphology of the coating and the electrical behaviour of the material. In contrast with non-functionalized GNPs, when NH2-functionalized GNPs were used, the nanoparticles adapted to the surface of the fibres causing a major effectiveness of the electrical network created along the fibres, achieving an electrical conductivity in the order of 10−2 S/m. The sensitivity values, obtained under tensile loads, reached values in the order of 840 up to 16400.

      PubDate: 2017-04-25T17:47:48Z
       
  • Effect of carboxylic polyphenylene sulfide on the micromechanical
           properties of polyphenylene sulfide/carbon fiber composites
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Hao-hao Ren, Dong-xia Xu, Guang-ming Yan, Gang Zhang, Xiao-jun Wang, Sheng-ru Long, Jie Yang
      The aim of this study was synthesis of the polyphenylene sulfide (PPS) containing carboxyl unit and investigation of the effect of modified PPS used as compatibilizer on the interfacial micromechanical properties of carbon fiber (CF) reinforced PPS composites. A series of copoly(1,4-phenylene sulfide)-poly(2,5-phenylene sulfide acid) (PPS-COOH)s containing different proportions of carboxyl units in the side chain were synthesized by the reaction of dihalogenated monomer and sodium sulfide via nucleophilic substitution polymerization under high pressure. According to the results of FT-IR, DSC, TGA, mechanical test and contact angle test, all of the copolymers were found to have analogous structure and improved hydrophilic property comparing with neat PPS. There was a good physical compatibility between the modified PPS and the pure PPS. The microbond test (measuring apparent interfacial shear strength (τapp) of the composite) and scanning electron microscopy (SEM) also showed that the optimized PPS-COOH (7.5) can be used to improve the micro-mechanical properties and interfacial bonding between CF and PPS matrix. The maximum τ app of 10%PPS-COOH (7.5)/PPS/CF composite was 49.1 MPa, which had increased 36.0% comparing with that of the pure PPS/CF composite (36.1 MPa).

      PubDate: 2017-04-25T17:47:48Z
       
  • Improvement of mechanical properties by a polydopamine interface in highly
           filled hierarchical composites of titanium dioxide particles and
           poly(vinyl butyral)
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): P. Georgopanos, E. Eichner, V. Filiz, U.A. Handge, G.A. Schneider, S. Heinrich, V. Abetz
      In this work, the preparation and properties of hierarchical composites of titanium dioxide (TiO2) particles (rutile modification) and poly(vinyl butyral) (PVB) are discussed. The volume fraction of the ceramic particles was approximately 60%. Two types of composites with different fillers were examined, i.e. TiO2 particles with and without a thin coating of polydopamine (PDA). A variety of characterization methods was applied in order to analyze the properties of the particles and the composites. Infrared spectroscopy is used to verify the functionalization of the particles with a thin polydopamine layer. Thermal analysis provides information on the thermal stability and the degree of functionalization of the coated particles and the composites. Scanning electron microscopy investigations reveal that the functionalized TiO2 particles with PDA form larger agglomerates which enable the coating of the TiO2 particles with PVB via the spouted bed technique. Nanoindentation experiments show that the final hierarchical composite material with the use of non-coated TiO2 particles exhibits a hardness of 0.75 ± 0.04 GPa and a Young's modulus of 29.5 ± 1.0 GPa. The composites containing polydopamine coated TiO2 particles show an increase of approximately 40% in hardness and 25% in Young's modulus in comparison to the composites with uncoated TiO2.

      PubDate: 2017-04-25T17:47:48Z
       
  • Radiation resistance of polypropylene composites by incorporating reduced
           graphene oxide and antioxidant: A comparison study
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Yu Lin, Yaohua Liu, Dongge Zhang, Guozhang Wu
      In this study, polypropylene (PP) composites were fabricated by incorporating reduced graphene oxide (RGO) sheets and antioxidant pentaerythritol tetra [β-(3, 5-di-tert-butyl-4-hydroxyphenyl)-propionate] (AO1010) to comparatively investigate the effect of graphene and antioxidant on the radiation resistance. Morphological observation and X-ray diffraction reveal the uniform dispersion of RGO. The incorporation of antioxidant is beneficial to the improved dispersion and exfoliation of RGO nanosheets in the PP matrix. The melting temperature decreases significantly with increasing irradiation dose, whereas the crystallinity remains almost unchanged for all the samples before and after irradiation. Tensile strength analysis demonstrates that incorporating RGO sheets is more effective for radiation protection at low doses, and adding AO1010 is more applicable to radiation resistance at high doses. Furthermore, the mechanical performance and the decomposition temperature of PP/AO1010/RGO composites by simultaneously incorporating 0.5 wt% AO1010 and 1.0 wt% RGO sheets are higher than that of PP/AO1010 and PP/RGO composites upon gamma irradiation at various doses, indicating an additive effect between RGO and AO1010 in retarding the radiation-induced degradation of PP composites. The intrinsic mechanism of radiation resistance is attributed to the free radical scavenging and oxygen barrier effect. The additive effect between RGO and AO1010 can substantially reduce the number of peroxy radicals and oxygen concentration in the composites, resulting in the remarkable improvement in radiation resistance.

      PubDate: 2017-04-25T17:47:48Z
       
  • Nanoporous SiO2 grafted aramid fibers with low thermal conductivity
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Song He, Guoxiang Sun, Xudong Cheng, Huaming Dai, Xianfeng Chen
      Silica aerogel is an excellent thermal insulation material for its mesoporous nanostructures In this study, the aramid fibers were grafted with the mesoporous structure of silica aerogel to reduce the fiber thermal conductivity through a serious process. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) results indicate that siloxane groups were successfully grafted onto the fiber surface through nitration, reduction and grafting with 3-glycidoxypropyltrimethoxysilane (GPTMS). After cohydrolysis with tetraethyl orthosilicate (TEOS), condensation, alkylation and ambient drying, SEM images of the as-prepared fibers showed that a mesoporous structure formed around the fiber surface. Si content within the as-prepared fiber was about 10.5 times higher than the fiber grafted with GPTMS. The fiber was covered with a mesoporous and hyperbranched network. As a result, the thermal conductivity of blanket consisting of the as-prepared aramid fibers, measured by transient hot-wire method, was obviously lower than that of the original ones, whereas the thermal stability changes little.
      Graphical abstract image

      PubDate: 2017-04-25T17:47:48Z
       
  • Relationship between electrical conductivity and spatial arrangements of
           carbon nanotubes in polystyrene nanocomposites: The effect of thermal
           annealing and plasticization on electrical conductivity
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Guoxia Fei, Qichun Gong, Dongxu Li, Marino Lavorgna, Hesheng Xia
      The effect of both thermal annealing and plasticization of the polymeric matrix by low molecular weight compounds on the electrical conductivity of the polystyrene based carbon nanotubes (CNTs) composites were investigated. It was found that the electrical conductivity of the samples filled with 3 wt% of CNTs increased by nearly 2 orders of magnitude after thermal annealing for 10 h at 150 °C, and it further increased with increasing plasticizer content. The effect of the hierarchical CNT morphology on the electrical conductivity of composites was elucidated by in-situ Raman and Synchrotron Radiation Small Angle X-ray Scattering investigations. The synergistic effect between thermal treatment and matrix plasticization contributes to efficiently eliminate the residual stress at the interface between polymeric matrix and carbon nanotubes. This leads to the formation of a more effective CNTs network featured by more dense bundles, exhibiting a larger number of contacts between the CNTs which contributes to significantly enhance the electrical conductivity of composites.
      Graphical abstract image

      PubDate: 2017-04-25T17:47:48Z
       
  • A high performance self-healing strain sensor with synergetic networks of
           poly(ɛ-caprolactone) microspheres, graphene and silver nanowires
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Shuqi Liu, Yong Lin, Yong Wei, Song Chen, Jiarong Zhu, Lan Liu
      Flexible strain sensors have been widely applied in wearable devices. However, few studies focus on the self-healing performance though this property is essential to practical applications due to the inevitability of irreversible mechanical damages/cracks in the reciprocating deformation. Here we report a simple and effective approach to fabricate a flexible strain sensor with a conductive composite layer by pouring liquid polydimethylsiloxane (PDMS) on the hybrids of poly(ɛ-caprolactone) microspheres (m-PCL), graphene oxide (GO) and silver nanowires (AgNWs). Through a multidimensional hybridization method, the hybrid fillers form a synergetic conductive network in which GO have good interactions with both m-PCL and AgNWs, thus covering m-PCL and anchoring AgNWs. Due to the synergetic effects of the m-PCL/GO/AgNWs (PGA) conductive network, the strain sensor shows high sensitivity (0.26 rad−1), good conductivity (0.45 S/cm), excellent durability (more than 2400 bending cycles) and outstanding repeatable self-healing property at moderate temperature (self-healed for more than 5 times at 80 °C in 3 min), ensuring the potential applications in wearable devices.

      PubDate: 2017-04-25T17:47:48Z
       
  • Evaluation and optimization of the magnetoelectric response of
           CoFe2O4/poly(vinylidene fluoride) composite spheres by computer simulation
           
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): C.S. Lehmann Fernández, N. Pereira, S. Lanceros-Méndez, P. Martins
      Magnetoelectric (ME) composites exhibiting strain-mediated coupling are gaining increasing interest for applications. The most interesting ones are composed of piezoelectric polymers and magnetostrictive particles. In particular, low dimensional ME materials, such as the ones in the form of micro- and nano-spheres, show strong potentials for improved energy harvesters with higher volume efficiency, sensors and actuators. Nevertheless the ME characterization of such low dimensional ME structures remain a difficult and challenging task and, therefore, the use of mathematical models and simulations are an interesting and viable option to better understand and tailor materials towards applications. In this context, the ME coupling on microspheres based on piezoelectric poly(vinylidene fluoride) (PVDF) and magnetostrictive CoFe2O4 (CFO) particles was theoretically studied based on Finite Element Methods (FEM). The effect of sphere size and filler content on the ME response was evaluated, showing that the ME response of CFO/PVDF microspheres is strongly influenced by the magnetic field intensity, sphere diameter and CFO content, being the highest ME response achieved on composite sphere with 90 wt% of CFO and 1.2 μm.

      PubDate: 2017-04-25T17:47:48Z
       
  • In-situ pressing synthesis of densely compacted carbon nanotubes
           reinforced nanocomposites with outstanding mechanical performance
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Yan-ge Yu, Jing Zhong, Jindun Liu, Guo-Xiang Zhou, Lan-Xiang Lv, Cheng-Yan Xu, Nikhil Koratkar
      Hot/cold pressing is a very common process in powder metallurgy and polymer industry, in which powders are compacted at a temperature/pressure high enough to induce sintering and creeping processes, and make the materials much denser and stronger. In this study, we extent this strategy to the synthesis of carbon nanotube (CNT) nanocomposites, yet with the high compressive stress generated naturally during the ultra-filtration process. Employing dead filtration, which is traditionally employed to extract solids from solution in water treatment process, we fabricate CNTs/PVA nanocomposites with high CNTs loading. It was found that this process not only greatly accelerates the filtration, but also generates significant in-situ pressure on the nanocomposites during its formation. Such pressure can compress the nanocomposites in-situ from the very onset of the formation of the nanocomposites and at molecular scale, which makes the nanocomposites densely compacted and eventually translates to very high mechanical properties even at high CNTs concentrations of up to ∼90 vol%. The tensile strength and Young's modulus can be increased by 435% and 859%, respectively, and the toughness is comparable with the nacre at similar content of inorganic constituent.

      PubDate: 2017-04-25T17:47:48Z
       
  • Damping of carbon fibre and flax fibre angle-ply composite laminates
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): M. Rueppel, J. Rion, C. Dransfeld, C. Fischer, K. Masania
      The damping behaviour of continuous carbon fibre and flax fibre reinforced polymer (CFRP and FFRP) composites was studied by comparing angle-ply laminates. Using logarithmic decrement measurements, dynamic mechanical analysis and vibration beam measurements, the damping was described as the specific damping capacity ψ in order to compare data using the different methods. Our results show approximately 2–3 times better damping of FFRP compared to CFRP at low frequency and low strain. We show that the damping of both materials increases with increasing angle-ply orientation below 300 Hz . While the matrix and interface seems to contribute mainly to damping at lower frequencies, the fibre shows an increasing contribution with ψ =  64.4 % for unidirectional FFRP at 1259 Hz in the 5 t h mode of vibration, without a notable change in the elastic modulus. This work demonstrates that the FFRP may be simultaneously stiff and efficient at damping.

      PubDate: 2017-04-18T08:26:01Z
       
  • Polymer bonded explosives with highly tunable creep resistance based on
           segmented polyurethane copolymers with different hard segment contents
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Congmei Lin, Qiang Tian, Keping Chen, Guansong He, Jianhu Zhang, Shijun Liu, László Almásy
      In this research, a group of segmented polyurethane (PU) copolymers with different hard segment (HS) contents were successfully synthesized. The microstructure of the PU copolymers was characterized via Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and small-angle neutron scattering (SANS). Then, the PU copolymers were selected as polymer binder for coating an insensitive high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) to prepare polymer bonded explosives (PBXs). When the HS concentration of PU copolymers increased from 14 to 34 wt %, a 14.6 times increase in the creep rupture time of PBXs under 60 °C/3 MPa and a 52.3% decrease in the steady-state creep strain rate under 60 °C/1 MPa were observed. The experimental results indicated that a wide variety of structure and properties of PU copolymer could be customizable through the adjustment of the HS contents, and consequently, provided an efficient route to tune the creep performance of the PBXs over a wide range.

      PubDate: 2017-04-18T08:26:01Z
       
  • Electrically and thermally conductive thin elastic polymer foils
           containing SiC nanofibers
    • Abstract: Publication date: 7 July 2017
      Source:Composites Science and Technology, Volume 146
      Author(s): Sandra Paszkiewicz, Iman Taraghi, Anna Szymczyk, Andrzej Huczko, Magdalena Kurcz, Bartlomiej Przybyszewski, Rafal Stanik, Amelia Linares, Tiberio A. Ezquerra, Zbigniew Rosłaniec
      Design and experiment of polymeric nanocomposites (NCs) for photovoltaic applications with outstanding electrical and thermal properties has been investigated with the introduction of SiC nanofibers (NFs) into the poly(trimethylene terephthalate)-block-poly(tetramethylene oxide) (PTT-PTMO) copolymers. In order to enhance the electrical and thermal conductivity, different concentrations of SiC NFs, ranging from 0.1 to 3.0 wt %, have been selected to mix with PTT-PTMO via in situ polymerization method. This reaction method is an excellent choice for incorporation of high amount of SiC NFs (3 wt %) into the polymer that was confirmed by morphological studies. From dielectric spectroscopy studies a percolating behavior was confirmed at low percolation threshold (less than 2% wt %). Furthermore, the 15% increment for thermal conductivity appeared with combination of 0.5 wt % SiC NFs with PTT-PTMO copolymers, which can be affected by manufacturing process of NCs, state of nanofillers dispersion and aspect ratio of nanofillers.
      Graphical abstract image

      PubDate: 2017-04-18T08:26:01Z
       
  • Thermoelectric properties of composite films prepared with
           benzodithiophene derivatives and carbon nanotubes
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Xiaoyan Zhou, Chengjun Pan, Ansheng Liang, Lei Wang, Wai-Yeung Wong
      Benzodithiophene (BDT)-based conjugated polymers have garnered considerable interest due to their planar backbones and improved carrier mobility, and have found wide application in organic field-effect transistors and organic photovoltaics. However, there are few reports on the use of these conjugated polymers as thermoelectric materials. In this work, the conjugated polymer poly(benzo[1,2-b:4,5-b’]dithiophene-alt-3,4-ethylenedioxythiophene) (PBDT-EDOT) was synthesized to investigate the thermoelectric behavior of its composite films with single-walled carbon nanotubes (SWCNTs). The polymer was characterized by 1H NMR, gel permeation chromatography, thermal gravimetric analysis and differential scanning calorimetry. The thermoelectric properties, carrier concentration and mobility of the composite films were also measured. It was found that the composite with an SWCNT content of 30% exhibited a high Seebeck coefficient of 82.1 μV K−1 at room temperature. Additionally, for composites with SWCNT contents below 90%, the power factors reached the highest values at the glass transition point of PBDT-EDOT in the temperature range of 300–400 K.

      PubDate: 2017-04-11T07:54:16Z
       
  • Designing, modeling and manufacturing of lightweight carbon
           nanotubes/polymer composite nanofibers for electromagnetic interference
           shielding application
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Komeil Nasouri, Ahmad Mousavi Shoushtari
      Lightweight conductive multi-walled carbon nanotubes (MWCNTs)/polyvinyl alcohol (PVA) composite nanofibers were prepared by electrospinning process with an aim to investigate the potential of such nanofibers as an effective electromagnetic interference (EMI) shielding material. The influence of MWCNTs content, thickness, and frequency on the EMI shielding of conductive MWCNTs/PVA composite nanofiber has been investigated. These experiments were designed by response surface methodology (RSM) and quadratic model was used to calculation of the responses. The predicted responses were in good agreement with the experimental results according to RSM model. The RSM analysis confirmed that MWCNTs content and thickness were the main significant variables affecting the absorption shielding effectiveness. Moreover, the sample thickness has no significant influence on the reflection shielding effectiveness. The RSM model predicted the 31.5 dB value of the highest absorption with low reflection (8.8 dB) at conditions of 7.7 wt% MWCNTs content, 3 mm of the sample thickness, and 12 GHz of incident EM wave frequency. The obtained RSM results confirmed that the selected RSM model presented suitable performance for evaluating the involved variables and prediction of EMI shielding parameters.

      PubDate: 2017-04-11T07:54:16Z
       
  • High through-plane thermal conductivity of polymer based product with
           vertical alignment of graphite flakes achieved via 3D printing
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Yunchao Jia, Hui He, Yi Geng, Bai Huang, Xiaodong Peng
      The polymer/graphite based products fabricated by conventional molding method possess limited through-plane thermal conductivities (TPTCs) because the graphite flakes are strongly aligned in the in-plane direction. Based on the characteristic of fused deposition modeling (FDM, a trendy technology of 3D printing), rational design of 3D printing (3DP) process can make the graphite flakes orient along the through-plane direction. In this paper, high TPTC of polymer/graphite based products with graphite flakes vertically aligned are achieved via FDM. Although lots of voids generated during the fused deposition process, the optimal product shows a high TPTC as 5.5 W m−1 K−1 because the fluent heat conductive pathways are not blocked by the voids. Finally, a heat sink with good thermally conductive property used for the 3D printer is successfully fabricated and it can well meet the heat dissipation requirement of 3D printer.

      PubDate: 2017-04-11T07:54:16Z
       
  • Bio-inspired and lanthanide-induced hierarchical sodium alginate/graphene
           oxide composite paper with enhanced physicochemical properties
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Shunli Liu, Jun Ling, Kewen Li, Fang Yao, Olayinka Oderinde, Zhihong Zhang, Guodong Fu
      This paper reports an artificial nacre-like composite paper based on sodium alginate (SA) and graphene oxide (GO) by lanthanide ions cross-linking. SA-coated GO were used as building “bricks and mortar” and self-assembled into aligned GO/SA composite hydrogel by the coordination of lanthanide ions. Subsequently, the hierarchical GO/SA composite paper was formed under evaporation. Four types of lanthanide ions (Nd3+, Ce3+, Gd3+, and Yb3+) were used to fabricate hierarchical GO/SA composite papers. The lanthanides enhanced the mechanical properties of the GO/SA composite papers (strength of 255.8 ± 8.52 MPa and toughness of 4.83 ± 0.28 MJ m−3) and endowed the papers with high stability. Due to the anisotropic nature along parallel and perpendicular directions, the hierarchical GO/SA composite papers exhibited a specific thermal conductivity. These features greatly expand the application of the composite papers, which are believed to show competitive advantages in aerospace, electronic devices, and thermal interface materials.

      PubDate: 2017-04-11T07:54:16Z
       
  • Effects of interfaces between adjacent layers on breakdown strength and
           energy density in sandwich-structured polymer composites
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Yao Wang, Yafang Hou, Yuan Deng
      Design of layered structures in polymer-based dielectric composites would result in regionalized distribution of fillers which is important in determining the electrical properties of the composites. Here, BaTiO3/poly(vinylidene fluoride) (BT/PVDF, denominated as B) composite layer and pure PVDF (denominated as P) layer were stacked in five different sequences to investigate the influence of interfaces formed between adjacent layers in sandwich structure on the breakdown strength of composites. B/P/B film showed the highest breakdown strength, suggesting that breakdown strength could be simply enhanced via forming two hetero-interfaces by inserting a pure polymer layer in the composite with filler homogenously distributed. Thus; the dielectric behavior and energy storage capability of B/P/B sandwich-structured composites with various BT volume fractions were studied. The significantly improved dielectric polarization and breakdown strengths were observed in B/P/B sandwich structure, where the interfaces between adjacent layers play the crucial role. Maximum discharged energy density near breakdown field was achieved at ultralow BT loading of 1 vol%. The results highlight the benefit from structural design of multilayer composites towards high-performance pulsed power systems.

      PubDate: 2017-04-11T07:54:16Z
       
  • Development and characterization of a new natural fiber reinforced
           thermoplastic (NFRP) with Cortaderia selloana (Pampa grass) short fibers
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): A. Jordá-Vilaplana, A. Carbonell-Verdú, M.D. Samper, A. Pop, D. Garcia-Sanoguera
      In this work, fully bio-based thermoplastic composites are manufactured with bio-based polyethylene (from sugarcane) and short fibers coming from Cortaderia selloana (CS) wastes. These wastes are characterized by high cellulose content, which can provide high stiffness to the polymeric matrix. The effect of Cortaderia selloana short fibers on thermal properties has been evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The effect of the filler load on mechanical properties has also been evaluated by tensile and impact tests as well as the effects of different coupling agents. Fiber-matrix interactions have been studied by scanning electron microscopy (SEM). The addition of 15–30 wt% Cortaderia selloana short fiber leads to high elastic and flexural modulus without remarkable changes in thermal degradation of the polymer composite.
      Graphical abstract image

      PubDate: 2017-04-04T03:25:35Z
       
  • Broadband composite radar absorbing structures with resistive frequency
           selective surface: Optimal design, manufacturing and characterization
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Weiwei Li, Mingji Chen, Zhihui Zeng, Hao Jin, Yongmao Pei, Zhong Zhang
      A series of composite radar absorbing structures (RAS) with resistive frequency selective surface (FSS) have been designed and optimized in high efficiency using the transfer matrix method together with the adaptive genetic algorithm. The composite structures show broadband absorption property verified by both numerical simulation and experimental measurement. Especially, the optimal 5 mm-thick composite RAS inserted with a single layer of resistive FSS can produce 90% absorption bandwidth of around 11.8 GHz, which is much wider compared with the multilayered metallic metamaterial absorber with the same thickness. The composite RAS can be easily manufactured by dielectric substrates in combination with screen-printed resistive FSSs.

      PubDate: 2017-04-04T03:25:35Z
       
  • Flame-retardant, non-irritating and self-healing multilayer films with
           double-network structure
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Hongyun Xuan, Jiaoyu Ren, Xizhang Wang, Jianhao Zhang, Liqin Ge
      Flame-retardant, non-irritating, and self-healing double-network films based on host–guest interaction were prepared on paper via layer-by-layer (LbL) assembly. The multilayer films are composed of poly (acrylic acid)-adamantanamine/ammonium polyphosphate-cross-poly (ethylenimine)-β-cyclodextrin (PAA-AD/APP-co-PEI-β-CD). After a mild reaction between APP and PEI-β-CD polymers, PAA-AD and APP-co-PEI-β-CD polymers form the novel double-network films via the host–guest interaction. The novel film can produce a self-healing surface without any initiating agents. Besides, when directly exposed to a flame, such films will generate foam char layers because of the intumescent effect, and will endow the print paper with a self-extinguishing property. The fire protection of the coatings was intensively investigated by a fire protection test, scanning electron microscopy (SEM), compressive strength test, thermogravimetric analysis (TGA), and real-time Fourier transform infrared spectroscopy (FTIR). The fire resistant films were found to have the best fire-protection effect under the low-cost and eco-friendly conditions. The films show potential applications as multifunctional advanced commercial supplies, such as papers, textiles, and wood.

      PubDate: 2017-04-04T03:25:35Z
       
  • Prediction of the crack density evolution in multidirectional laminates
           under fatigue loadings
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): P.A. Carraro, L. Maragoni, M. Quaresimin
      An innovative procedure is proposed for the prediction of the crack density evolution in multidirectional laminates subjected to cyclic loadings. The crack initiation and propagation phases are treated separately and described by means of a master S-N curve and a Paris-like curve, respectively. A damage-based multiscale strategy is adopted for the prediction of multiple crack initiation, accounting for the statistical distribution of fatigue strength and crack propagation resistance within a ply. The procedure has been implemented in a Matlab® code for the simulation of the fatigue damage evolution in multi-directional symmetric laminates. Comparisons with experimental results taken from previous works show a very good agreement.

      PubDate: 2017-04-04T03:25:35Z
       
 
 
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