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  Subjects -> ENGINEERING (Total: 2279 journals)
    - CHEMICAL ENGINEERING (191 journals)
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    - ENGINEERING (1203 journals)
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ENGINEERING (1203 journals)                  1 2 3 4 5 6 7 | 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: 222)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
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: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
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)
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: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 20)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 24)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
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: 12)
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: 37)
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: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 9)
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 Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
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)
Arid Zone Journal of Engineering, Technology and Environment     Open Access  
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
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: 8)
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: 8)
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: 4)
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: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 32)
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: 2)
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     Hybrid Journal   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
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: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
Coatings     Open Access   (Followers: 3)
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: 25)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 256)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 181)
Composites Part B : Engineering     Hybrid Journal   (Followers: 227)
Composites Science and Technology     Hybrid Journal   (Followers: 169)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 13)
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: 28)
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: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 29)
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: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access  

        1 2 3 4 5 6 7 | Last

Journal Cover Composites Science and Technology
  [SJR: 1.512]   [H-I: 144]   [169 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0266-3538
   Published by Elsevier Homepage  [3034 journals]
  • Clay/carbon nanotube hybrid mixture to reduce the electrical percolation
           threshold of polymer nanocomposites
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): Mohammed H. Al-Saleh
      Creating electrically conductive polymer composites with extremely low nanofiller concentration by melt compounding is a major research challenge. At low nanofiller concentration, the valuable properties of polymers are preserved and the feasibility of the composite is promoted. In this work, an organically modified clay (OMC) was utilized to alter the structure and consequently the electrical resistivity of carbon nanotubes (CNT)/polypropylene (PP) composite. As a result of OMC incorporation, the electrical percolation threshold concentration (EPTC) was reduced from 1.0 wt% CNT for the CNT/PP composite to 0.5 wt% CNT for the CNT:OMC/PP composite, corresponding to 50% reduction in the amount of CNT. The macro-dispersion analysis did not reveal any significant difference between the dispersion of CNT in the CNT/PP and CNT:OMC/PP composites. However, the processing behavior analysis showed a significant decrease in mixing torque and consequently mixing energy due to the addition of OMC. The decrease in mixing torque and/or mixing energy decreases the destruction of CNT aspect ratio. In addition, the DSC analysis showed a decrease in composite crystallinity due to OMC addition. This finding reveals a thinner insulating crystalline layer at the surface of CNT particles and consequently higher electrical conductivity. Based on these experimental findings, it can be speculated that the addition of OMC promoted the conductivity of the composite by decreasing the mixing shear stress and/or polymer crystallinity.

      PubDate: 2017-06-22T01:12:25Z
       
  • A facile method to prepare flexible boron nitride/poly(vinyl alcohol)
           composites with enhanced thermal conductivity
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): Jun Zhang, Xiaona Wang, Cuiping Yu, Qiulong Li, Zhuo Li, Chaowei Li, Huifen Lu, Qichong Zhang, Jingxin Zhao, Ming Hu, Yagang Yao
      Polymer infiltrating filler-network has been actively researched recently to obtain composite materials with enhanced thermal conductivities. However, the long infiltration time blocks its wide application. In this study, we prepared hexagonal boron nitride (h-BN)/poly(vinyl alcohol) (PVA) composite by combining polymer infiltration with filler diffusion through the polymer to reduce infiltration time and form heat conduction paths. Base on this process, the maximum thermal conductivities of the obtained h-BN/PVA composites were 1.63 W/m·K and 8.44 W/m·K along the through-plane and in-plane directions, respectively. In addition, the composites displayed excellent heat dissipation performance when attached on top of a light emitting diode (LED) light strip. The research results indicate our approach is facile and capable of fabricating high performance thermal interface materials.

      PubDate: 2017-06-22T01:12:25Z
       
  • Effect of temperature on the electrical property of epoxy composites with
           carbon nanotube
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): Shen Gong, Yang Wang, Zhu Xiao, Zhou Li, Zhi X. Wang, Ruo S. Lei, Zheng H. Zhu
      Eliminating the influence of environment temperature is critical for high-accuracy carbon nanotube polymer nanocomposites sensors. In this work, the temperature effects on the nanocomposite are studied by both experiment investigation and simulation calculation. Nearly constant resistance values were found at a CNT loading around 3 wt%. By considering the temperature effect and CNT structural distortion in the developed percolation network model, simulation results agree well with experimental data. On this basis, results show that the thermally assisted tunneling on CNT junctions and thermal expansion of polymer matrix are the two core mechanisms, relaxed CNT junctions in CNT/polymer nanocomposite depressed the temperature effect, and the influence of environment temperature could be significantly reduced by adjusting CNT loadings and choosing a matching polymer matrix. All of these findings will benefit for the design of high-accuracy sensors.

      PubDate: 2017-06-22T01:12:25Z
       
  • Improved mechanical properties of carbon fiber-reinforced epoxy composites
           by growing carbon black on carbon fiber surface
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): Jidong Dong, Chuyuan Jia, Mingqiang Wang, Xiaojiao Fang, Huawei Wei, Huaquan Xie, Tong Zhang, Jinmei He, Zaixing Jiang, Yudong Huang
      The interfacial properties between carbon fiber (CF) and matrix play a key role in the mechanical properties of carbon fiber composites. To improve the mechanical properties of fibers/epoxy composites without sacrificing tensile strength of base fibers, carbon black (CB) was introduced onto the surface of CFs by chemical vapour deposition (CVD). The distribution of CBs on the fiber surface and the change of the surface roughness were analyzed, using scanning electron microscopy (SEM) and atomic force microscope (AFM). Raman spectroscopy indicated that the defects of CF surface were repaired by CB. The wettability and surface energy of modified CFs increased obviously in comparison with those of the untreated CFs. Meanwhile, a significant increase of interlaminar shear strength (ILSS), interface shear strength tests (IFSS) and impact property were achieved in the 5-min-modified CFs, which was 22.0, 44.4 and 22.7%, respectively. In addition, the tensile strength (TS) of modified CFs showed a slight increase compared with that of untreated CFs.

      PubDate: 2017-06-22T01:12:25Z
       
  • Mapping fibre failure in situ in carbon fibre reinforced polymers by fast
           synchrotron X-ray computed tomography
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): S.C. Garcea, I. Sinclair, S.M. Spearing, P.J. Withers
      Fast, in situ synchrotron X-ray computed tomography (CT) has been used to capture damage evolution, particularly fibre failures, before final fracture (within 99.9% of the ultimate tensile stress) in cross-ply carbon fibre/epoxy coupons under continuous monotonic tensile loading for the first time. It is noteworthy that fewer than 8% of the fibres in the 0° plies have fractured at 99.9% of the failure load. The majority of fibre breaks appear as isolated events, although some instances of multiple adjacent breaks (clusters) do occur at intermediate and high stress levels. Contrary to conventional wisdom, a cluster of failed fibres always occurred in a burst as a singular failure event: clusters were never seen to accumulate additional broken fibres as load increased suggesting low-level stress concentration local to fibre breaks. Several instances of multiple fractures along individual fibres were observed, providing an estimation of the critical stress transfer length between the fibre and matrix. The factors affecting fibre failure appear to be complex, with distinct sample-to-sample variability being identified for the length-scale tested. This highlights the need for improved understanding of the mechanisms that contribute to final failure, particularly criteria controlling the arrest or otherwise of clustered fracture events.

      PubDate: 2017-06-22T01:12:25Z
       
  • Vitrification during cure produces anomalies and path-dependence in
           electrical resistance of conductive composites
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): Geoffrey Rivers, Pearl Lee-Sullivan, Boxin Zhao
      Using a DGEBA/TETA epoxy filled with silver microflakes, we sought to investigate if the onset of conductivity would approximately obey the power-law as cure progresses, as reported in the open literature. We monitored the resistivity change as a function of cure and vitrification behaviour, using a set of concurrent experiments; in-situ four-wire electrical resistance measurements in a newly-developed probe-mold device, and differential scanning calorimetry. It was evident that the electrical conductivity evolved very differently depending on heating conditions, the composite glass transition temperature, and filler content. Periods were observed during cure where electrical conductivity was disrupted, attributed to stresses produced by vitrification. This produced as much as 1500-fold increases in final developed electrical resistance depending on heating conditions and composite glass transition properties, for the same conductive filler content. This discovery has far ranging implications on the industry practice of applying multi-step cure schedules that feature vitrification during cure.

      PubDate: 2017-06-22T01:12:25Z
       
  • Effect of sisal and hydrothermal ageing on the dielectric behaviour of
           polylactide/sisal biocomposites
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): J.D. Badia, P. Reig-Rodrigo, R. Teruel-Juanes, T. Kittikorn, E. Strömberg, M. Ek, S. Karlsson, A. Ribes-Greus
      The dielectric properties of virgin polylactide (PLA) and its reinforced composites with different weight amounts of sisal fibres were assessed at broad temperature (from −130 °C to 130 °C) and frequency ranges (from 10−2–107 Hz), before and after being subjected to accelerated hydrothermal ageing. The synergetic effects of both the loading of sisal and hydrothermal ageing were analysed by means of dielectric relaxation spectra. The relaxation time functions were evaluated by the Havriliak-Negami model, substracting the ohmic contribution of conductivity. The intramolecular and intermolecular relaxations were respectively analysed by means of Arrhenius and Vogel-Fulcher-Tammann-Hesse thermal activation models. The addition of fibre increased the number of hydrogen bonds, which incremented the dielectric permittivity and mainly hindered the non-cooperative relaxations of the biocomposites by increasing the activation energy. Hydrothermal ageing enhanced the formation of the crystalline phase at the so-called transcrystalline region along sisal. This fact hindered the movement of the amorphous PLA fraction, and consequently decreased the dielectric permittivity and increased the dynamic fragility.
      Graphical abstract image

      PubDate: 2017-06-12T01:33:25Z
       
  • Thermally-induced in situ growth of ZnO nanoparticles in polymeric fibrous
           membranes
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): Davide Morselli, Paola Valentini, Giovanni Perotto, Alice Scarpellini, Pier Paolo Pompa, Athanassia Athanassiou, Despina Fragouli
      We present a two-step process to obtain PMMA fibrous membranes with homogeneously in situ synthesized zinc oxide nanoparticles of defined shape and size, both on the fibers' surface and bulk. The method is based on the electrospinning of PMMA/precursor solutions and the subsequent thermally activated in situ conversion of zinc acetate to zinc oxide nanoparticles directly in the solid polymeric fibers. X-ray diffraction measurements ensure the formation of crystalline ZnO nanoparticles. Scanning and transmission electron microscopy prove that homogeneously distributed nanoparticles with two different morphologies and size distributions are obtained, depending on the area of the fibers where the nanoparticles are nucleated and on the initial precursor's content. In particular, branched nanoparticles homogeneously decorate the fibers' surface with their dimensions that range from 50 nm to 140 nm for initial precursor contents from 23 to 40 wt%, respectively. On the other hand, small spherical nanoparticles of ca. 7 nm are mainly observed in the bulk of the fibers. Unlike the branched nanoparticles, the dimensions of the spherical nanoparticles are practically unaffected by the precursor amount initially loaded. The homogeneously distributed nanoparticles both on the surface and in the bulk of the polymeric fibers, combined with the high surface area provided by the fibrous structure, result in a multifunctional material characterized by reversible UV-induced wettability and water permeability, improved thermal stability and antibacterial activity particularly promising for diverse applications such as filtration, wound management, photocatalysis, antibacterial and UV-shielding textiles.
      Graphical abstract image

      PubDate: 2017-06-12T01:33:25Z
       
  • In-situ curing of glass fiber reinforced polymer composites via resistive
           heating of carbon nanotube films
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): Xiaokui Xu, Yuan Zhang, Jin Jiang, Han Wang, Xinluo Zhao, Qingwen Li, Weibang Lu
      In this study, we report a time- and energy-saving out-of-oven curing process based on the resistive heating of a macroscale carbon nanotube (CNT) film made using the floating catalyst chemical vapor deposition method. CNT film can be heated up very quickly when connected to an electrical power source. By coating CNT film onto the surface of uncured glass fiber reinforced polymer composites, the composites can be cured by the resistive heating of the CNT film. The degree of cure, loss storage, and tensile properties of the composites made from the new process are almost the same as those made from the traditional oven heating process. However, the new curing process is much faster, and its energy consumption is found to be only one seventh that of the oven curing process. The deicing of glass fiber composites based on the resistive heating of CNT film is also demonstrated.

      PubDate: 2017-06-12T01:33:25Z
       
  • Design and characterization for dual-band and multi-band A-sandwich
           composite radome walls
    • Abstract: Publication date: 8 September 2017
      Source:Composites Science and Technology, Volume 149
      Author(s): Licheng Zhou, Peiyu Wang, Yongmao Pei, Anmin Zeng, Liqun Tang, Zejia Liu, Yiping Liu, Zhenyu Jiang, Daining Fang
      Nowadays, radomes that are employed to protect antennas inside from physical environment are required to have dual-band or even multi-band transmission performance. In this paper, a design scheme based on the theory of small reflections is proposed for the design of dual-band and multi-band A-sandwich radomes. Subsequently, two A-sandwich composite radome walls are designed and fabricated according to the design scheme. Finally, both numerical simulations and experiments are conducted to verify the electromagnetic characteristics of the radome walls. Results indicate that one of the A-sandwich radome walls has two passbands in 4.0–11.4 GHz and 25.2–40.0 GHz, while the other one has three passbands in 4.0–8.2 GHz, 18.0–20.5 GHz, and 29.1–40.0 GHz, respectively. The proposed method is experimentally demonstrated to be an effective approach for designing dual-band and multi-band dielectric radome walls for both centimeter and millimeter wave applications.

      PubDate: 2017-06-12T01:33:25Z
       
  • Triglycidyl para-aminophenol modified montmorillonites for epoxy
           nanocomposites and multi-scale carbon fiber reinforced composites with
           superior mechanical properties
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Mao Peng, Yang Zhou, Guodoong Zhou, Huichao Yao
      Multi-scale carbon fiber reinforced polymer (CFRP) composites with continuous carbon fiber as the primary reinforcement and nanoscale fillers as the secondary reinforcement have attracted great research interests in the last decade. Herein we report a new organically modified montmorillonite (MMT) for epoxy nanocomposites and multi-scale CFRP composites with superior mechanical properties. The organically modified MMT is prepared by ion-exchanging natural MMT with the hydrochlorate of triglycidyl para-aminophenol (TGPAP), a tertiary amine-type epoxy oligomer used as a CFRP matrix for the aerospace industry. The TGPAP-modified MMTs disperse uniformly in the matrix as thin stacks of intercalated nanoplatelets and exfoliated single-layer nanoplatelets, and are reactive with the epoxy matrices, thus remarkably enhance the mechanical properties of the nanocomposites and multi-scale CFRP composites. In contrast to reference CFRP composites, the incorporation TGPAP-modified MMTs greatly retards the propagation of inter-layer delamination, and fiber breakage becomes the major damage mode in the three-point bending tests. In particular, 4 wt% of TGPAP-modified MMTs increases the interlaminar shear strength of the multi-scale CFRP composites by 52%, and the flexural strength by 52.3%, which is superior to those of MMT-containing CFRP composites ever reported.

      PubDate: 2017-06-02T12:59:12Z
       
  • Incorporation of supramolecular polymer-functionalized graphene: Towards
           the development of bio-based high electrically conductive polymeric
           nanocomposites
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Chih-Chia Cheng, Zhi-Sheng Liao, Jyun-Jie Huang, Shan-You Huang, Wen-Lu Fan
      Supramolecular polymer-functionalized graphene (SPFG), a combination of exfoliated graphite nanoplatelets and a low-molecular-weight supramolecular polymer, can be incorporated into poly(L-lactic acid) (PLLA) matrices for efficient production of SPFG/PLLA composites; SPFG behaves as a highly efficient reinforcing material and substantially improves the overall physical properties compared to commercial PLLA. The SPFG content of the PLLA composites can be readily adjusted to obtain the desired composite products with specific crystallization and mechanical characteristics. At the optimized blending ratio of 10 wt% SPFG and 90 wt% PLLA, the resulting film exhibited a 65.2% lower oxygen permeation rate and two-fold higher ultimate tensile strength (47.8 MPa) than pristine PLLA. More excitingly, this newly-developed composite possessed superior electrical conductivity of up to 9.58 × 10−3 S/cm at a SPFG loading of 10.0 wt%, which was nearly four orders of magnitude higher than control graphite/PLLA composites at the same nanofiller content. Thus, SPFG provides a potential route towards the development of high performance graphene-based PLLA nanocomposites for a broad range of electronic and biomedical applications.
      Graphical abstract image

      PubDate: 2017-06-02T12:59:12Z
       
  • Developing heat conduction pathways through short polymer chains in a
           hydrogen bonded polymer system
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Nitin Mehra, Liwen Mu, Jiahua Zhu
      In the past couple of decades, high thermally conductive fillers are extensively used to develop thermally conductive polymer based composites. Such conventional methods suffer from wide variety of problems especially related to fabrication, high-cost, poor mechanical properties etc. Though covalent bonds in single polymer chain can lead to very high thermal conduction, it is irony that bulk polymers are thermal insulators due to significant phonon scattering. In this work, we have shown how by engineering intermolecular interaction within the polymer chain, one can create continuous thermal network which in turn drives thermal conduction in polymer without using any traditional fillers. Thermal conduction pathways were introduced in a blend film of long chain polymer Poly (vinyl alcohol) (PVA) and short chain Poly (ethylene glycol) (PEG). Thermal conductivity enhancement of around 1.6 times of neat polymer was achieved. The critical factor responsible for thermal conduction in these films was found to be homogeneous distribution of “thermal bridges” formed by hydrogen bonding between PVA and short PEG chain. Reduction in thermal conductivity was observed when PVA blend film with longer PEG chain, which is mainly due to poor thermal bridges distribution and chain agglomeration. This work presents a fascinating yet promising non-conventional method to make thermally conductive polymer based material without using traditional fillers for thermal management applications.
      Graphical abstract image

      PubDate: 2017-06-02T12:59:12Z
       
  • Graphene coated piezo-resistive fabrics for liquid composite molding
           process monitoring
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Muhammad A. Ali, Rehan Umer, Kamran A. Khan, Yarjan A. Samad, Kin Liao, Wesley Cantwell
      In this study, the graphene coated piezo-resistive fabrics have been exploited for liquid composite molding process monitoring. The utility of this novel technique has been demonstrated through compaction and flow monitoring experiments. The coated fabrics are subjected to a series of compaction tests to monitor resistance changes during the compaction cycle. During mechanical compression, the change in resistance has been found to be inversely proportional to the strain associated with the applied load. The repeatability of the change in the electrical resistance is confirmed via a series of vacuum assisted, stepwise and cyclic compression tests. The overall sensitivity of around 30% change in resistance is observed. The results highlight very small differences between the wet and dry compaction cycles when using silicone oil as the test fluid, suggesting that a nonconductive fluid offers negligible interference in the graphene coatings. The fabrics are subsequently used in a full resin infusion cycle to monitor the resistance change during the filling and post-filling stages. A continuous change in the resistance of the fabric is observed during, and after resin infusion process, highlighting the applicability of this novel technique for full process monitoring during the compaction and resin flow stages, in addition to cure monitoring.

      PubDate: 2017-06-02T12:59:12Z
       
  • Single fibre model composite: Interfacial shear strength measurements
           between reactive polyamide-6 and cellulosic or glass fibres by
           microdroplet pullout test
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Baptiste Paul Revol, Matthieu Thomassey, Frédéric Ruch, Michel Bouquey, Michel Nardin
      This work aims to study the effect of reactive molding on polyamide-6 (PA6) based micro composites with either glass or high tenacity viscose as fibre reinforcements. For this purpose, microdroplet pullout test was found to be well suited to determine the interfacial shear strength. For pull-out testing, samples are prepared with a common method implying melting polyamide-6 and an innovative method which allows the microdroplets formation by direct wetting in the reactive mixture. Conditions to obtain microdroplet in this new method are close to those of real size composite molding. First, this work focus on the verification of the new sample preparation method using 1H and 13C NMR to determine conversion rate and verify the presence of polyamide-6 on wetted fibres bundles. Contact angle are calculated to confirm the NMR analysis conclusions. Both of these analyses confirm that PA6 is effectively formed on fibres when wetting with the reactive mixture. Finally, interfacial shear strength is compared for both glass and high tenacity viscose with these two types of preparation procedures. Obtained values for glass fibres are τ = 25 ± 6 MPa with PA6-melting and τ = 20 ± 3 MPa with reactive mixture wetting. Reactive mixture wetting also allows to avoid high tenacity viscose degradation during PA6 formation, leading to the determination of the interfacial shear strength τ = 12 ± 3 MPa.

      PubDate: 2017-05-28T05:37:22Z
       
  • Improved dielectric properties of polypropylene-based nanocomposites via
           co-filling with zinc oxide and barium titanate
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Jinzhao Hu, Liang Zhang, Zhi-Min Dang, Dongrui Wang
      Tetra-needle-shaped zinc oxide whiskers (T-ZnOw) and barium titanate (BT) nanoparticles were embedded into polypropylene (PP) matrix to construct ternary nanocomposites with improved dielectric properties. The nanocomposites were fabricated via a melt blending and subsequent compression molding approach. The microstructure, crystallization behavior, and dielectric properties of as-fabricated nanocomposites were investigated in detail. Results reveal that the selecting processing approach could afford isotropic nanocomposites with T-ZnOw and BT nanoparticles homogeneously dispersed throughout the PP matrix. The T-ZnOw/PP binary composites exhibited typical characteristics of percolation system with a relatively small threshold of 13 vol%. When the content of T-ZnOw approaching the percolation threshold, the dielectric constant and loss tangent of the binary composites were dramatically enhanced. After introducing BT nanoparticles, the resultant ternary composites showed further improved dielectric performance. For the ternary T-ZnOw/BT/PP with the BT content of 15 vol% and T-ZnOw content of 9.76 vol%, dielectric constant and loss tangent at 1 kHz reached 11 and 0.04, respectively.

      PubDate: 2017-05-28T05:37:22Z
       
  • Development of adaptive pleated fiber reinforced plastic composites
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Moniruddoza Ashir, Jan Hindahl, Andreas Nocke, Chokri Cherif
      Fiber reinforced plastics are being used as different niche products in automotive, aerospace and plant engineering industries due to their lightweight potential and superior mechanical properties in comparison with traditionally used materials. Using structurally integrated actuators, single-axis and joint free adaptive fiber reinforced plastic components can be realized. In this work, the development of adaptive pleated fiber reinforced plastics based on shape memory alloys is reported. Furthermore, simulation supported deformation behavior of developed samples is investigated by varying the pleat height, pleat thickness and the spacing between two pleats. The deformation behavior of the adaptive pleated fiber reinforced plastics predominantly depends on the pleat height and spacing between two pleats.

      PubDate: 2017-05-28T05:37:22Z
       
  • Constructing interconnected graphene network in fluoroelastomer composites
           by F-H polar interaction for enhanced mechanical and barrier properties
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Yun-hui Wu, Yong Lin, Yong Wei, Song Chen, Shu-qi Liu, Lan Liu
      Graphene is one of the most promising fillers for functional nanocomposites due to its high strength, high conductivity and high specific surface area, etc. However, its poor interfacial compatibility makes it difficult to simultaneously satisfy high strength and low gas permeability of nanocomposites. Herein, we proposed a novel strategy to regulate interfacial adhesion by fluorine-hydrogen (F-H) polar interaction in the FKM composites. The F-H polar interactions effectively induce the graphene oxide (GO) interact with the chain of fluoroelastomer (FKM) in spatial arrangements on molecular-level, promoting the construction of interconnected GO network. Specifically, a 10-fold increase in tensile strength of FKM/GO-5 with the incorporation of 5 phr GO is realized compared with pure FKM, and the oxygen permeability of FKM/GO-5 decreases by 79%. At the same filler contents, FKM/GO-5 composites exhibit higher mechanical property and lower gas permeability compared with FKM/rGO composites. Such enhanced performances make FKM/GO composites with an interconnected network very competitive for potential applications as multi-functional structural materials. The proposed strategy provides a novel effective approach for developing and designing the high-performances fluorine-based polymer nanocomposites.

      PubDate: 2017-05-28T05:37:22Z
       
  • Nanohybrid shish-kebab supramolecular structure of single-walled carbon
           nanotubes/N,N′-dioctyl perylene tetracarboxylic diimide
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Ping Li, Jun-Huan Li, Bin Fan, Jun-Ting Xu, Zhi-Qiang Fan
      In the present work, carbon nanotubes (CNTs)-induced solution crystallization of N, N′-dioctyl perylene tetracarboxylic diimide (PTCDI-C8) in o-dichlorobenzene was studied. It is found that the nanohybrid shish-kebab (NHSK) supramolecular structure, wherein the single-walled carbon nanotubes (SWCNTs) serve as the shish and PTCDI-C8 crystals are the kebabs, with regular arrangement of the kebabs can be formed. UV–vis, photoluminescence spectroscopy and XPS studies reveal that there exist strong π-π interaction between PTCDI-C8 and SWCNTs, and some PTCDI-C8 molecules are already adsorbed on SWCNTs surface prior to crystallization. This is the first example of NHSK structure formed by CNTs and organic small molecules. Nevertheless, multi-walled carbon nanotubes (MWCNTs) cannot induce PTCDI-C8 to form NHSK structure under the same conditions. This indicates that geometric confinement may be the predominant factor affecting the orientation of the pre-adsorbed PTCDI-C8 molecules and epitaxial growth of the crystals.
      Graphical abstract image

      PubDate: 2017-05-28T05:37:22Z
       
  • Carbon fibre surface modification using functionalized nanoclay: A
           hierarchical interphase for fibre-reinforced polymer composites
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Omid Zabihi, Mojtaba Ahmadi, Quanxiang Li, Sajjad Shafei, Mickey G. Huson, Minoo Naebe
      Low interface strength is a common challenge in taking full advantage of excellent physical performances of carbon fibre (CF) reinforced polymer composites. Herein, for the first time, we have used amino-functionalized nanoclay as a linkage between CF surface and epoxy matrix, which by a cation exchange process was grafted on the CF surface. Amino-functionalized nanoclay significantly increased surface roughness, coefficient of friction, and BET surface area of CF. The results showed that nanoclay-based modification does not change the tensile strength and Weibull modulus of CF significantly however, both specific and dispersive surface energies, obtained by inverse gas chromatography technique, were increased. A high compatibility of nanoclay-based modified CF (clay@CF) with epoxy resin was also observed by analysing the contact angle between epoxy droplets and fibre surface. Moreover, single fibre fragmentation tests (SFFT) alongside fractographic observations showed that the length of fibre pull-out and the size of cracks between the fibre and matrix were outstandingly reduced in clay@CF in comparison to untreated CF, demonstrating that the stress transfer and interfacial shear strength (IFSS) have been significantly improved.

      PubDate: 2017-05-28T05:37:22Z
       
  • PLA toughened by bamboo cellulose nanowhiskers: Role of silane
           compatibilization on the PLA bionanocomposite properties
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Shaoping Qian, Kuichuan Sheng
      To toughen brittle poly(lactic acid) (PLA) composites, surface-modified bamboo cellulose nanowhiskers (BCNW) were introduced into a PLA matrix. The BCNW was treated with (3-mercaptopropyl)trimethoxysilane (A-189) at five concentrations between 1 wt% to 16 wt% to improve compatibility. Silylated BCNW-toughened PLA composite films were further fabricated by solution casting. The coupled reaction between A-189 and cellulose via Si-O-C bonding and hydrogen bonding was confirmed. BCNW was silylated uniformly and maintained its original morphology. With increasing concentration, BCNW became smooth; however, with excessive coupling agent, the BCNW surface became rough. Elongation at break was inversely proportional to tensile strength and tensile modulus. Elongation at break increased to 250.8% after the 4 wt% A-189 treatment compared to 12.35% with untreated composites. The C/O ratio of BCNW decreased after coupling agent treatment. There were physical interlocks and hydrogen bonding between two phases. A wire-drawing phenomenon was observed on the tensile fractural surface. The thermal degradation stability decreased with the increasing treatment concentration.

      PubDate: 2017-05-28T05:37:22Z
       
  • Dynamic properties of hybrid composite structures based multiwalled carbon
           nanotubes
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): H. Benyahia, M. Tarfaoui, V. Datsyuk, A. El Moumen, S. Trotsenko, S. Reich
      The present paper investigates an experimental approach concerning the determination of dynamic behavior and damage kinetics of composite materials based on multiwalled carbon nanotubes (MWCNTs), embedded in electrospun reactive nanofibers in the Taylor impact test. Different impact energies have been considered namely; 21J and 39J to investigate the composite response. Projectiles are manufactured from a commercial steel 2071 with a nominal diameter of 50 mm and 1600 g of weight. The projectile was fired against a composite specimen initially hooked on a cell effort by a compressed gas gun within the velocity of 5 m/s and 7 m/s. Three types of specimens are considered: (1) MAT1 (carbon fiber reinforced epoxy polymer composite), MAT2 (consists of MAT1 and electrospun Polybenzmideazole-Bismaleimide (PBI-BMI) nanofibermats between carbon fiber layers) and MAT3 (consists of MAT2, where PBI-BMI nanofibermats are reinforced with multiwalled carbon nanotubes (MWCNTs)). The effect of the MWCNTs on the dynamic properties of the composite structures was studied. Microscope observations reveal damage progressive, buckling and crush-front propagation during tests. Application of the PBI-BMI reactive nanofibermats reinforced with MWCNTs leads to damage prevention, reducing damage area in composite samples.

      PubDate: 2017-05-28T05:37:22Z
       
  • MgO nanoparticles-decorated carbon fibers hybrid for improving thermal
           conductive and electrical insulating properties of Nylon 6 composite
    • Abstract: Publication date: 18 August 2017
      Source:Composites Science and Technology, Volume 148
      Author(s): Jingxin Zhang, Zhongjie Du, Wei Zou, Hangquan Li, Chen Zhang
      A magnesium oxide (MgO) nanoparticles-decorated carbon fiber hybrid (CFMgO) were designed and fabricated as thermal conductive but electric insulating filler for polymer matrix. Carbon fibers (CF) and MgO nanoparticles were firstly treated by the coupling agents with amine groups and epoxy groups, respectively. Then CFMgO was constructed through grafting the nanoparticles onto the surface of the fiber. It was expected that the thermal conductivity of CF would be enhanced but its electrical conductivity would be inhibited by the coating of MgO nanoparticles. The chemical structure and morphology of CFMgO were investigated using Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). Finally, the hybrid filler was introduced into Nylon 6. The strong interfacial interaction between the filler and matrix was exhibited, attributed to the existence of the coupling agents and the rough surface of nanoparticles-decorated CF. The highest thermal conductivity reached 0.748 W/m·K at 20 wt % addition of CFMgO. Meanwhile, the insulation of the composite appeared at higher than 10 wt% addition of the hybrid filler. Furthermore, connected by MgO nanoparticles, less CF was necessary for the construction of heat conduction channel, and lower value of percolation threshold was achieved.

      PubDate: 2017-05-23T06:14:15Z
       
  • Impact of the spatial distribution of high content of carbon nanotubes on
           the electrical conductivity of glass fiber fabrics/epoxy composites
           fabricated by RTM technique
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Delong He, Diana Salem, Jacques Cinquin, Gérard-Pascal Piau, Jinbo Bai
      To incorporate high content of carbon nanotubes (CNTs) into a polymer matrix is greatly desired to obtain highly conductive structural composites, but it is difficult in practice to be realized due to increased resin viscosity along with dispersion difficulty. In this study, we demonstrate the production of carbon nanotubes (CNTs)-integrated glass fiber fabrics (GFF)/epoxy composites by resin transfer molding (RTM), in which the mass fraction of CNTs on GFF varies from 0 to as high as 8 wt%. Three different methods were compared to load CNTs on GFFs, which include one-step in-situ CVD growth, catalyst pre-deposited two-step CVD growth and CNT suspension casting. For each type of CNTs-GFFs, a series of RTM composites with varied CNT contents were prepared. The impact of the CNT spatial distribution on the composite in-plane and through-plane electrical conductivities was compared at different CNT loading levels by subtracting contact resistance between the sample and the electrodes. It was found that the composites reinforced with one-step CVD-grown CNTs/GFFs show the best electrical conductivity among the three types of the composites studied, due to good CNT structure and their alignment on GF surface. A detailed discussion was made on the composite conductive behavior with the different CNTs-GFFs. This study helps to provide insight to the production of high-performance structural composites functionalized with high contents of CNTs at low cost.

      PubDate: 2017-05-23T06:14:15Z
       
  • Reinforcement efficiency of carbon nanotubes and their effect on
           crystal-crystal slip in poly(ether ketone)/carbon nanotube composite
           fibers
    • Abstract: Publication date: 28 July 2017
      Source:Composites Science and Technology, Volume 147
      Author(s): Bradley A. Newcomb, Han Gi Chae, Lindsey Thomson, Jeffrey Luo, Jong-Beom Baek, Satish Kumar
      Poly(ether ketone) (PEK)/carbon nanotube (CNT) composite fibers have been produced using dry-jet wet spinning. Carbon nanofibers (CNF), few-walled carbon nanotubes (FWNT), and multi-walled nanotubes (MWNT) have been utilized as nanofillers, with few-walled carbon nanotube loadings as high as 28 wt%. The interfacial strength of the PEK/FWNT and PEK/MWNT fibers were evaluated through the monitoring of the G-mode Raman peak shift as a function of fiber strain. Interfacial shear strengths as high as 14.2 MPa were measured for the PEK/FWNT fiber with 28 wt% CNT loading, a 1320% increase as compared to the PEK/MWNT fiber with 5 wt% loading (1.0 MPa). T g of the PEK/FWNT fibers increased by 19 °C as the FWNT loading was increased from 5 wt% to 28 wt%. A second peak in the tan δ behavior of all PEK/CNT fibers was also observed. This second tan δ peak (T ∼ 240 °C–250 °C) is attributed to the α*-transition (crystal-crystal slip) in the PEK crystalline regions, and its presence is more pronounced (higher magnitude of tan δ) in all PEK/FWNT fibers as compared to PEK/MWNT and PEK/CNF fibers. FWNTs are restricting the mobility of the amorphous PEK as evidenced by the increasing T g . Enhanced PEK crystal-crystal slip corresponds to increasing large scale chain mobility in the crystalline regions of the PEK at T α* . We propose a model which correlates the increase in PEK-FWNT interfacial shear strength to an increase in large scale chain mobility where crystal-crystal slip precedes failure of PEK/CNT interface at T α* for the PEK/FWNT fibers.

      PubDate: 2017-05-23T06:14:15Z
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
 
 
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