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  Subjects -> ENGINEERING (Total: 2266 journals)
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ENGINEERING (1195 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: 1)
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: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 6)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Artificial Neural Systems     Open Access   (Followers: 3)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 18)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
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: 29)
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: 28)
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: 5)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 6)
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)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 4)
Applied Sciences     Open Access   (Followers: 3)
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: 8)
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: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
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: 4)
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: 223)
Composites Science and Technology     Hybrid Journal   (Followers: 164)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 25)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 8)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 25)
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: 7)
Control Engineering Practice     Hybrid Journal   (Followers: 40)
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  
Current Applied Physics     Full-text available via subscription   (Followers: 4)

        1 2 3 4 5 6 | Last

Journal Cover Composites Science and Technology
  [SJR: 1.512]   [H-I: 144]   [164 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0266-3538
   Published by Elsevier Homepage  [3032 journals]
  • 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
       
  • Design for a cruciform coupon used for tensile biaxial transverse tests on
           composite materials
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): E. Correa, A. Barroso, M.D. Pérez, F. París
      This paper focuses on the design of the appropriate geometry for cruciform coupons conceived to be tested under tensile biaxial transverse loads. To this end, Finite Element models were developed and their results were used to propose a geometry which minimizes undesirable effects such as stress concentrations, develops a uniform state of biaxial stresses in the central zone of the coupon and assures that the failure takes place at this zone. The experimental results confirm the validity of the numerical models.

      PubDate: 2017-04-18T08:26:01Z
       
  • A novel cool material: ASA (acrylonitrile-styrene-acrylate) matrix
           composites with solar reflective inorganic particles
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Bo Xiang, Xiuping Yin, Jun Zhang
      Nowadays, the undesirable heat generated from solar energy troubles people a lot in various aspects, including the energy consumption for cooling purposes, the potential safety hazards of the outdoor devices used in high-temperature environment and so on. Therefore, many cool materials emerge as the times require, which can mitigate these serious situation. In this study, a concept of solar reflective ASA (acrylonitrile-styrene-acrylate terpolymer) for cool material was proposed. To achieve this purpose, several inorganic particles with high solar reflectance were chosen to mix with ASA via melt blending to improve the cooling property of ASA. Ultraviolet-visible-near infrared (UV-Vis-NIR) spectral and temperature test were carried out to evaluate the cooling properties of ASA and its hybrid composites. The results of the solar spectral test showed that the addition of only 1% volume fraction of inorganic particles could effectively improve the solar reflectance of ASA. And ASA/barium titanate (BaTiO3) hybrid composite possessed the highest reflectance value of 67.66%, nearly 2 times that of neat ASA. The results of the indoor temperature test were in highly consistent with those of the solar reflectance, which showed that all the hybrid composites presented better cooling effect compared with neat ASA. Also, ASA/BaTiO3 hybrid composite exhibited the best cooling effect, nearly 10 °C lower than neat ASA. Besides, the outdoor temperature test showed the same trend with the indoor temperature test. Furthermore, the results of the mechanic test indicated that the improvement of the cooling properties was based on no sacrifice of the mechanical properties.

      PubDate: 2017-04-18T08:26:01Z
       
  • Preparation of polymer/clay nanocomposites via melt intercalation under
           continuous elongation flow
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Guizhen Zhang, Ting Wu, Wangyang Lin, Yongbin Tan, Rongyuan Chen, Zhaoxia Huang, Xiaochun Yin, Jinping Qu
      Polymer/clay nanocomposites exhibit desirable performance and multifunctional properties. The ideal dispersion and exfoliation of clay layers in polymeric matrixes is a significant drawback that affects its application. In this study, a novel extruder generating a continuous elongation flow was used to fabricate the representative polypropylene (PP)/organic montmorillonite (OMMT) nanocomposites and then compare with the twin-screw extruder (TSE). Phase morphology, dynamic rheological properties, and mechanical properties were characterized by thermal gravimetric analysis, wide-angle X-ray diffraction, transmission electron microscopy, rotational rheometer and impact tests. The morphology and rheological behavior of the nanocomposites evidenced that ideal intercalation or/and exfoliation dispersion of OMMT in PP matrixes can be achieved under continuous elongation flow. Thus, the double-side exfoliation of the OMMT platelets combined with the pulling/diffusion process under an elongation flow is leading to an effective strengthening and toughening of PP better than that in the TSE.

      PubDate: 2017-04-18T08:26:01Z
       
  • Fabrication of a thin and lightweight microwave absorber containing
           Ni-coated glass fibers by electroless plating
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Young-Woo Nam, Jae-Hun Choi, Won-Jun Lee, Chun-Gon Kim
      This study presents a thin and lightweight single-slab and two types of double-slab microwave absorbing composites by coating Ni to a glass fiber via an electroless plating technique. In contrast to conventional absorber production processes that use nano-conductive particles, such as carbon black, carbon nanotubes, and carbon nanofibers, this newly proposed absorber applies a very thin conductive coating on a glass fiber through an electroless plating technique, involving mass production, to obtain the designed permittivity with excellent performance and a reflection loss below −10 dB (90% absorption) in the X-band (8.2–12.4 GHz) without using nano-conductive particles. The designed total thicknesses of the newly proposed single-slab and two types of double-slab absorbers correspond to 1.84 mm, 2.03 mm, and 2.29 mm, respectively. Although the newly proposed two types of double-slab absorbers are lightweight and very thin when compared to conventional absorbers, they exhibit excellent absorption performance in the almost X-band. The interlaminar shear strength was verified according to ASTM D-2344 by using a Ni-coated glass/epoxy composite to examine the mechanical performance of the proposed composite structure. From an electrical and mechanical performance viewpoint, the results confirm that the newly proposed absorber with Ni-coated glass fibers offers significant potential applications in stealth technology.

      PubDate: 2017-04-18T08:26:01Z
       
  • Fracture toughness enhancement of thermoplastic/epoxy blends by the
           plastic yield of toughening agents: A multiscale analysis
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Hyunseong Shin, Byungjo Kim, Jin-Gyu Han, Man Young Lee, Jong Kyoo Park, Maenghyo Cho
      We propose a strategy of multiscale analysis to predict enhancements in fracture toughness of thermoplastic/epoxy blends by the plastic yield of toughening agents. As main mechanisms of toughness enhancement of thermoplastic/epoxy blends, we considered plastic deformation in the material near the macroscopic crack tip, and particle bridging in the crack wake. The proposed multiscale model is validated through the reported experimental data. Using the proposed multiscale model, some useful guidelines for the proper selection of toughening agent were devised.

      PubDate: 2017-04-18T08:26:01Z
       
  • A method for quantitative characterization of agglomeration degree in
           nanocomposites
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): A. Golbang, M.H.N. Famili, M. Mokhtari Motameni Shirvan
      Dispersion and agglomeration control the macroscopic properties of nanocomposites; thus, quantitative characterization of particle dispersion and agglomeration is crucial. So far, methods such as image analysis or measurement of macroscopic properties have been insufficient. So, a novel methodology is introduced to predict particle dispersion and agglomeration degree quantitatively through the measurement of effective dielectric constant. This is done by taking into account the impact of inter-particle interactions in respect to microstructure for the calculation of effective dielectric constant. Inter-particle interaction is calculated as a function of inter-particle distance for random dispersion of particles in composites and as a function of agglomerate size and packing density for nanocomposites with agglomerated microstructure. The inter-particle interactions increase with increase in filler content and agglomeration. This increment is abrupt at percolation where inter-particle distance is significantly reduced. Experimental data from ZnO/PS composites with controlled inter-particle distance and agglomeration confirm the theoretical results.

      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
       
  • The cell growth-induced orientation of mica in lightweight flexible poly
           (vinyl chloride) foams and its enhancement on sound insulation
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Lifu Xu, Teng Han, Jiang Li, Ying Xiong, Shaoyun Guo
      The lightweight flexible poly(vinyl chloride) (PVC)/mica composite foams with low density (0.51 g/cm3) which is 40–60% reduction and high sound insulation performance (an average STL of 28.3 dB) were prepared in this work. And the influences of mica content and foaming time on the cell morphology, mica distribution, and sound transmission loss (STL) were investigated. It was observed that the PVC/mica foams not only showed good sound insulation properties, but also maintained ultra-light in weight when the mica content was below 10 wt%. In addition, as the foaming time became longer, the cell density increased and the cell-wall thickness decreased. As a result, the bi-axial stretching induced by the cell growth would drive the mica platelets to orient along the thin cell walls, which significantly increased the sound insulation properties. Simultaneously, the flexibility and reusability of the foams were tested by cyclic compression. When the mica content was below 10 wt%, the PVC/mica composite foams showed low compressive stress and low permanent strain.

      PubDate: 2017-04-11T07:54:16Z
       
  • Facile pyrolysis preparation of rosin-derived biochar for supporting
           silver nanoparticles with antibacterial activity
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Jian-Fei Huang, Qing-Shan Shi, Jin Feng, Ming-Jie Chen, Wen-Ru Li, Liang-Qiu Li
      The incorporation of metallic nanoparticles (NPs) into a biomass-based matrix has been intensively investigated because the obtained nanocomposites exhibited effective antibacterial activity to intractable resistance of bacteria. However, the nanocomposites present limitations, such as a multi-step preparation process and a low loading capacity of nanoparticles. A facile preparation route for the preparation of antibacterial metallic nanocomposites would be especially beneficial for industrial fabrication. In this study, we provided a facile strategy for the preparation of a rosin-derived biochar matrix loaded with silver nanoparticles (Ag NPs) as the fillers. The results demonstrated that the preparation of these rosin-derived biochar silver nanocomposites (Rc/Ag nanocomposites) was achieved by a rapid pyrolysis process and a large amount of Ag NPs were in-situ obtained and homogeneously dispersed on the matrix. More importantly, these materials exhibited satisfying antibacterial activities against E. coli and S. aureus. Thus, the Rc/Ag nanocomposites exhibit promising filler for wooden furniture against bacterial infection and could be used as a filter for indoor antibacterial air filtration.

      PubDate: 2017-04-11T07:54:16Z
       
  • Deployable, shape memory carbon fibre composites without shape memory
           constituents
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Paul Robinson, Alexander Bismarck, Bohao Zhang, Henry A. Maples
      Trials have been conducted to investigate the shape memory capability of an interleaved composite consisting of carbon fibre reinforced epoxy laminae and polystyrene interleaf layers. It has been shown that the composite can be readily re-shaped by deforming it at an elevated temperature and then cooling the composite in the deformed state. On re-heating, the composite almost fully returns to its original shape. One potential application of the shape memory capability of the interleaved composite is in deployable structures and a simple structure has been manufactured to demonstrate this possibility.

      PubDate: 2017-04-11T07:54:16Z
       
  • Dielectric response and breakdown behavior of polymer-ceramic
           nanocomposites: The effect of nanoparticle distribution
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Ziming Cai, Xiaohui Wang, Bingcheng Luo, Wei Hong, Longwen Wu, Longtu Li
      Polymer-ceramic nanocomposites play an essential role in the application of pulsed power system, due to their ultrahigh power density and fast charging–discharging capability. It is very promising for them to be applied in energy storage capacitors and hybrid electric vehicles for the recent progressing in the improving energy density. The volume fraction, morphology, size, aspect ratio and distribution of ceramic particles have been reported to have significant effect on the dielectric response and breakdown strength of nanocomposites, which are two main factors that determine the energy density of nanocomposites. In this study, we introduce a quantified method to describe the distribution of ceramic nanoparticles in polymer matrix, then focus on the effect of nanoparticles distribution on dielectric response and breakdown strength of nanocomposites through finite element method and phase field method. Results indicate that the non-uniform distribution of ceramic nanoparticles will aggravate the concentration of local electric field, thus slightly enhance the dielectric response but seriously decrease the breakdown strength of nanocomposites. To verify the size effect of ceramic particles on breakdown strength of nanocomposites, three types of well distributed nanoparticles with different diameter of particles have also been calculated using the same method.

      PubDate: 2017-04-11T07:54:16Z
       
  • Characterization of enhanced interfacial bonding between epoxy and plasma
           functionalized carbon nanotube films
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Xiaohua Liu, Fujun Xu, Kun Zhang, Baochun Wei, Zhiqiang Gao, Yiping Qiu
      The interfacial bonding between carbon nanotube (CNT) films and epoxy is usually fairly weak for high quality composites and difficult to be measured experimentally. In this study, the interfacial bonding strength between a CNT film and epoxy is measured using a peeling test. The CNT/epoxy interfacial bonding strength is altered by surface functionalization of the CNT film using atmospheric pressure helium/oxygen plasma. Furthermore, composites with the control and the modified CNT film impregnated in epoxy are manufactured, and their mechanical properties including peeling strengths and tensile strengths are improved remarkably due to enhanced CNT/epoxy bonding after plasma functionalization. The peeling strength between the CNT film and epoxy is increased by 156.6% and so is the fracture energy. The tensile strength of the functionalized CNT film/epoxy composites is 74.4% higher than that with original CNT film. The effect of the treatment time (0.1, 0.2 and 0.3s) is assessed by surface chemical and physical analyses, showing an improvement in the amount of oxygen-containing functional groups on CNT surface, and better dispersion of the CNTs in ethanol with increased treatment time. This benefits the wetting and infiltration into CNTs by epoxy to obtain a stronger interfacial bonding.

      PubDate: 2017-04-11T07:54:16Z
       
  • Sulfonated bacterial cellulose/polyaniline composite membrane for use as
           gel polymer electrolyte
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Lina Yue, Yajie Xie, Yudong Zheng, Wei He, Shaolin Guo, Yi Sun, Tao Zhang, Shumin Liu
      Gel polymer electrolyte (GPE) with high ionic conductivity and stable electrochemical characteristics have great importance to the application in fuel cells, biological cells and other fields. In this study, bacterial cellulose (BC) was firstly modified by sulfonation to get sulfonated BC (SBC) for the first time. Then a novel sulfonated BC/polyaniline (SBC/PANI) composite GPE was synthesized in situ by oxidative polymerization of aniline onto SBC nanofibers successfully. The structure, microstructure, thermal stability and electrochemistry property of the SBC/PANI composite GPEs were tested and compared. The results showed that the ionic conductivity and ion exchange capacity of the SBC/PANI composite GPEs were associated with the degree of sulfonation (DS). At the DS of 41.87%, the ionic conductivity and ion exchange capacity could be improved to 5.2 × 10−3 S cm−1 and 3.92 mequiv. g−1, respectively. The electrochemical stability window could meet the application requirement of a variety of biocells and fuel cells. The cytotoxicity of the composites was also evaluated using cell counting kit-8 (CCK-8) assay in vitro and turned out that mesenchymal stem cells (MSCs) could adhere to the surface of the membrane and proliferate normally.

      PubDate: 2017-04-11T07:54:16Z
       
  • The sound insulation property of composite from waste printed circuit
           board and unsaturated polyester
    • Abstract: Publication date: 16 June 2017
      Source:Composites Science and Technology, Volume 145
      Author(s): Jun Cai, Qiang Fu, Mingce Long, Guofeng Liao, Zhenming Xu
      The sound insulation property of Waste printed circuit boards (WPCBs)/unsaturated polyester (UP) composite plate has been investigated. The effect of WPCB particle size and mass ratio on the surface density, elastic modulus and weighted sound reduction index has been studied. The results showed that WPCB addition caused the surface density increase especially for coarse particle because of the metal particle existence. The elastic modulus value was susceptible to the UP sufficiency to high WPCB mass ratio. The WPCB-UP composite plate shows sound insulation application potential because the maximum weighted sound reduction index of composite plate with particle size <0.71 mm reaches 28.4 dB. The composite sound transmission loss, which is the sound insulation property at different frequency, was measured by the four-microphone impedance tube method in the frequency range from 100 to 3150 Hz. The theoretic resonance frequencies predicted by the stiffness and mass laws were close to the experimental ones. The STL difference in stiffness-controlled region was more obvious than that in mass-controlled region because the addition of WPCB leaded to much greater increase in the stiffness than that in surface density.

      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
       
  • An unusual coral-like morphology for composites of
           poly(3,4-ethylenedioxythiophene)/carbon nanotube and the enhanced
           thermoelectric performance
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Xincheng Hu, Guangming Chen, Xin Wang
      We present an unusual coral-like coating morphology for the poly(3,4-ethylenedioxythiophene)/carbon nanotube (PEDOT/CNT) composites with dramatically improved thermoelectric performance. First, the PEDOT/CNT composites are prepared via chemical oxidation polymerization procedure in reverse microemulsions, using hexane or xylene as the reaction medium. The composite films exhibit excellent mechanical flexibility against bending and twisting. Then, the cable-like (in hexane) or coral-like (in xylene) morphology for the thick and uniform coating layer is directly proved by field-emission scanning electron microscopic images. Subsequently, their thermoelectric performances are quantitatively measured at room temperature. After that, the ordered arrangement structures of PEDOT macromolecules, the level of doping and the level of oxidation are investigated by X-ray diffraction technique and X-ray photoelectron spectra, respectively. Finally, the molecular mechanism for the enhanced thermoelectric performance is discussed.

      PubDate: 2017-03-27T14:41:31Z
       
  • Numerical prediction of fiber orientation and mechanical performance for
           short/long glass and carbon fiber-reinforced composites
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Huan-Chang Tseng, Rong-Yeu Chang, Chia-Hsiang Hsu
      Fiber reinforced polymer (FRP) composites offer exciting new possibilities for the green automotive industry, owing to their excellent mechanical properties, advantageous weight reduction and economical fuel consumption. In practice, accurately predicting fiber orientation is a critical issue in causing anisotropy in the mechanical properties of the FRP parts. Recently, an objective fiber orientation model, iARD-RPR (Improved Anisotropic Rotary Diffusion model combined with a Retarding Principal Rate model) proved significant in the field of fiber suspension rheology. Using state-of-the-art injection molding simulations, we therefore used the iARD-RPR model to explore the fiber orientation changes for various fiber components in regard to fiber length (short and long fibers) and fiber type (glass and carbon fibers). Under an extreme condition of higher fiber concentration and longer fiber lengths, a thicker core region and a narrow shell are always found in a typical orientation pattern of injection molded FRT parts. More importantly, these predicted orientation distributions provided to micromechanical material modeling computation of mechanical properties aid in the discussion on the reinforcing ability of short/long fibers and glass/carbon fibers based on the numerical simulation results. Comparisons with experimental data are also presented herein.

      PubDate: 2017-03-27T14:41:31Z
       
  • Highly anisotropic Cu oblate ellipsoids incorporated polymer composites
           with excellent performance for broadband electromagnetic interference
           shielding
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Seung Hwan Lee, Seunggun Yu, Faisal Shahzad, Jun Pyo Hong, Woo Nyon Kim, Cheolmin Park, Soon Man Hong, Chong Min Koo
      In this study, highly anisotropic Cu oblate ellipsoids incorporated polymer composites were prepared that revealed excellent broadband electromagnetic shielding effectiveness of 80.0 to 62.1 dB at a frequency region between 300.0 KHz and 12.0 GHz, at low Cu contents. Cu-coated hollow polymer beads were fabricated through electroless plating of Cu on the polymer hollow beads. The hollow polymer beads were prepared through thermal expansion of acrylonitrile-based polymer beads containing a blowing agent. These beads were capable of incorporating highly anisotropic 2-dimensional (2D) Cu oblate ellipsoids into polymer composite through simple compression molding process. The resulting broadband electromagnetic shielding performance attributes to a low percolation behavior of the composites due to high anisotropy of the conductive Cu filler and their multilayered structure in the composites.

      PubDate: 2017-03-27T14:41:31Z
       
  • BN@PPS core-shell structure particles and their 3D segregated architecture
           composites with high thermal conductivities
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Yue Jiang, Yujing Liu, Peng Min, Guoxin Sui
      Hexagonal boron nitride (h-BN) presents an excellent thermal conductivity and the outstanding insulating property for electronic packaging. However, a traditional method can enhance the thermal conductivity of the composites by melt mixing fillers and polymers usually leading to composites with limited thermal conductivity. Here, BN@PPS (Polyphenylene sulfide) core-shell structure particles and their composites with the 3D segregated architecture are presented. The composite achieves a high thermal conductivity of 4.15 W/mK containing 40 vol% BN, which is 16 times higher than that of PPS resin of ∼0.25 W/mK and 1.69 times higher than that PPS/BN blend composite with at the same BN loading of 2.45 W/mK. The outstanding thermally conductive property of segregated architecture PPS/BN composite is attributed to the formation of BN flakes networks in the PPS matrices, which can provide effective thermal conductive pathway. This segregated architecture composite is an optimal material for insulating electronic packaging.

      PubDate: 2017-03-27T14:41:31Z
       
  • Enhanced thermal conduction and influence of interfacial resistance within
           flexible high aspect ratio copper nanowire/polymer composites
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Amit Rai, Arden L. Moore
      Large quantities of high aspect ratio copper nanowires were synthesized from copper chloride using a simple solution-based method. The thermal conductivity of copper nanowire/polydimethylsiloxane and copper nanowire/polyurethane composites at different volume percentage loading from 0 to 4.1% were studied. At the highest loading, the thermal conductivity of both composite types increased more than threefold compared to the thermal conductivity values of the neat polymers. A hydrogen annealing process was implemented prior to mixing for select samples in an attempt to reduce performance-limiting thermal interface resistance between contacting nanowires and at nanowire/polymer matrix interfaces. Two separate theoretical models were used to study the effects of hydrogen annealing on the thermal conductivity of the composites and interfacial thermal resistance. In terms of potential as a substrate for flexible electronics, thermal imaging of a concentrated heat source on both neat polymer and composite samples showed that the resulting hot spot was significantly less severe when using the composite samples.

      PubDate: 2017-03-27T14:41:31Z
       
  • Poly (vinylidene fluoride) based percolative dielectrics with tunable
           coating of polydopamine on carbon nanotubes: Toward high permittivity and
           low dielectric loss
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Jiaming Zhu, Xiaoying Ji, Min Yin, Shaoyun Guo, Jiabin Shen
      Polydopamine (PDA) coated carbon nanotube (CNT)/poly (vinylidene fluoride) (PVDF) dielectric composites were fabricated through self-polymerization of dopamine hydrochloride (DAH) monomers. Microscopic observation substantiated that the thickness of PDA coatings on CNTs was tunable by varying the DAH/CNT ratios. When the PDA@CNTs were incorporated into the PVDF matrix, the electrical resistivity of the PDA@CNT/PVDF increased up with the thickening of PDA coatings, due to the inhibition of the direct contact between adjacent conductive particles. Considering the negative influence of current leakage on dielectric loss, the contribution of PDA coatings on dielectric behaviors of CNT/PVDF systems was compared at a similar resistivity. The results exhibited that accompanied with the enrichment of PDA contents, a more competitive balance between permittivity and loss factor was achieved. As an example, when 0.1 wt% 0.03PDA@CNTs were replaced by 0.2 wt% 0.2PDA@CNTs, the permittivity at 103 Hz was increased from 154 to 315 and the loss factor was reduced from 0.92 to 0.35. This indicated that the dielectric loss induced by the current leakage was suppressed when the conductive particles were coated by PDA layers. Accordingly, it can be regarded as one of strategies to make the percolative systems achieve high permittivity and low dielectric loss.

      PubDate: 2017-03-27T14:41:31Z
       
  • Roles of carbon nanotube and BaTiO3 nanofiber in the electrical,
           dielectric and piezoelectric properties of flexible nanocomposite
           generators
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Jing Yan, Young Gyu Jeong
      We report the electrical, dielectric and piezoelectric properties of flexible PDMS-based nanocomposite generators, which are tunable by different contents of multi-walled carbon nanotube (MWCNT, 0.0–5.0 wt%) and BaTiO3 nanofiber (10–50 wt%). The BaTiO3 nanofiber with tetragonal structure was manufactured by an electrospinning and following calcination process. For the first series of nanocomposite generators with 30 wt% BaTiO3 nanofiber and 0.0–5.0 wt% MWCNT, both electrical and dielectric properties were dramatically enhanced at a critical MWCNT content of 0.47 wt% owing to the formation of percolating networks of MWCNT in the presence of BaTiO3 nanofibers, as verified by SEM analysis. Accordingly, the nanocomposite generator with 30 wt% BaTiO3 and 5.0 wt% MWCNT achieved the highest conductivity of 0.12 S/cm and dielectric constant of 4474 at 1 kHz, whereas the nanocomposite generator with 30 wt% BaTiO3 and 2.0 wt% MWCNT attained the best piezoelectric performance by harvesting average output voltage of ∼3.00 V, current of ∼0.82 μA, and power of ∼0.14 μW. In cases of the second series of nanocomposite generators with 2.0 wt% MWCNT and 10–50 wt% BaTiO3 nanofiber, the electrical conductivity and dielectric constant increased with the increment of BaTiO3 content up to 40 wt%. Overall, the nanocomposite generator with 2.0 wt% MWCNT and 40 wt% BaTiO3 nanofiber generated the highest average output voltage of ∼3.73 V, current of ∼1.37 μA, and power of ∼0.33 μW, which was feasible to light up commercial LEDs and to charge a capacitor after rectification, revealing the potentiality in powering self-sufficient nanodevices and wireless electronics.

      PubDate: 2017-03-20T13:08:49Z
       
  • Novel functional silica nanoparticles for rubber vulcanization and
           reinforcement
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Lijuan Chen, Zhixin Jia, Yuhan Tang, Lianghui Wu, Yuanfang Luo, Demin Jia
      A high reactive sulfocompound, sulfur monochloride, was chemically supported onto the surface of silica (silica-s-S2Cl2) by the reaction between chloric atom and silanol hydroxyl to obtain a novel vulcanizing agent, silica supported sulfur monochloride (silica-s-S2Cl2). Silica-s-S2Cl2 can be homogeneously dispersed in SBR matrix as a modifier and cure the styrene-butadiene rubber (SBR) without sulfur as a novel high-efficiency vulcanizing agent. The sulfur and Bis[3-(triethoxysilyl)propyl] Tetrasulfide (TESPT) silane coupling agent vulcanized SBR composites were mainly polysulfide crosslinks, on the contrary, the vulcanization by silica-s-S2Cl2 give priority to the mono- and disulfides crosslinks. The highlight of this work lies in the fact that apparent improvement has been achieved by novel and high efficient functional particles due to the silica surface supported with sulfur monochloride, which may open up new opportunities for the preparation of functional nano-fillers in rubber industry.

      PubDate: 2017-03-20T13:08:49Z
       
  • The mechanical behavior of CNT reinforced nanocomposites assuming
           imperfect interfacial bonding between matrix and nanoparticles and
           percolation of interphase regions
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Yasser Zare, Kyong Yop Rhee
      The effective inverse aspect ratio (αeff) and volume fraction ( φ e f f ) of nanoparticles in polymer/CNT nanocomposites are defined accounting imperfect interfacial adhesion between polymer matrix and nanoparticles and percolation of interfacial regions as interphase percolation. After that, the tensile modulus and strength of nanocomposites are expressed by Halpin-Tsai and Pukanszky models to show the effects of radius (R) and length (l) of nanoparticles as well as the interphase thickness (t) and interfacial shear strength (τ) on the mechanical properties of nanocomposites. The best levels of “αeff” and “ φ e f f ” are obtained by the thinnest and the longest nanotubes as well as the highest values of “t” and “τ” factors. The best relative modulus of 8 is calculated by R < 13 nm and l > 6500 nm, while the strength slightly improves by R < 17 nm. Likewise, the relative modulus of 9 is calculated at t > 20 nm and τ > 170 MPa, while the best relative strength of 4.5 is shown at the highest levels of t = 25 nm and τ = 300 MPa. Conclusively, the interphase properties further affect the mechanical properties of nanocomposites compared to material parameters.

      PubDate: 2017-03-20T13:08:49Z
       
  • Computational micromechanics of fiber kinking in unidirectional FRP under
           different environmental conditions
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): F. Naya, M. Herráez, C.S. Lopes, C. González, S. Van der Veen, F. Pons
      The determination of ply properties of Fiber Reinforced Polymers (FRP) for particular operational environmental conditions in aeronautical applications is mandatory in order to fulfill current industry stringent certification requirements. However, the traditional experimental approach requires massive investments of resources and time. From the behaviour obtained experimentally, constitutive equations including failure criteria are then devised to be used in the design of FRP structures. The ply longitudinal behaviour under compression is generally the most difficult to measure and characterize. In this work, an alternative coupled experimental-computational micromechanics approach is proposed to determine the longitudinal compression properties of unidirectional FRP plies under different environmental conditions. This methodology includes experimental characterization of matrix and fiber/matrix interface, combined with numerical simulations of realistic microstructures. The interface decohesion is simulated using cohesive-frictional interactions. A pressure dependent, elasto-plastic model that includes tensile damage is employed to capture the matrix nonlinear behaviour. The numerical predictions match the experimentally-obtained ply properties available in the literature in a remarkable way and suggest that virtual ply property characterization is a mature and reliable approach to conduct screening of materials.

      PubDate: 2017-03-20T13:08:49Z
       
  • High thermal conductivity and excellent electrical insulation performance
           in double-percolated three-phase polymer nanocomposites
    • Abstract: Publication date: 26 May 2017
      Source:Composites Science and Technology, Volume 144
      Author(s): Dong-Li Zhang, Jun-Wei Zha, Chao-Qun Li, Wei-Kang Li, Si-Jiao Wang, Yongqiang Wen, Zhi-Min Dang
      High voltage direct current (HVDC) cable is attracting more attention during power transmission due to its many advantages. However, the accumulation of space charge, poor breakdown strength and low thermal conductivity of cable insulation layer have been a long-standing obstacle to utilize the HVDC cable applications. Because boron nitride nanosheets (BNNSs) are increasingly demanded in high thermal conductivity insulation materials, herein we report a facile and easy way to prepare styrene-(ethylene-co-butylene)-styrene tri-block copolymer/polypropylene (SEBS/PP) blends filled with BNNSs based on the construction of thermal conductive networks with double-percolation process. The morphology, thermal, and electrical properties of the BNNSs/SEBS/PP nanocomposites were investigated. Scanning electron microscopy showed that the BNNSs were well dispersed in the SEBS phase at low loading of 3 phr. The analysis results on electrical properties illustrated that the direct current (DC) breakdown strength and space charge suppression were remarkably improved by the introduction of BNNSs. In addition, the thermal conductivity of SEBS/PP blends (0.42 W m−1 K−1) was increased to 1.38 W m−1 K−1 when doped with 3 phr BNNSs. This nanocomposites with enhanced thermal conductivity and electrical properties have great potential to be used as recyclable insulating materials for HVDC.

      PubDate: 2017-03-20T13:08:49Z
       
 
 
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