Showing papers in "Polymer Composites in 2017"
TL;DR: An overview of biocomposite application in the automotives via a documentation of their history, chronology and progressive steps taken to break into the production lines of a number of key auto makers is provided in this article.
Abstract: The article provides an overview of biocomposite application in the automotives via a documentation of their history, chronology and progressive steps taken to break into the production lines of a number of key auto makers. It offers a detailed analysis of the key factors that have motivated the research and subsequent adoption of biocomposites; taking a peek at the advantages, disadvantages, and challenges experienced in the process. Auto makers and parts suppliers that have been a force behind this campaign, have also been accorded a fair share in the article. Future projection of role of these materials in the industry; with the ideas well dressed in form of bio concept cars caps up the paper. Automotive refers to; passenger cars, sport utility vehicles, vans, trucks, buses, and recreational vehicles. POLYM. COMPOS., 38:2553–2569, 2017. © 2016 Society of Plastics Engineers
235 citations
TL;DR: In this paper, the authors introduced a kind of novel composites with surface insulation modified metal aluminum cores to form multilayer coating structures as fillers in polyimide matrix for electronic applications.
Abstract: Significant progress has been made recently in developing the organic–inorganic composites with high thermal conductivity, low dielectric constant, and dielectric loss, for applications in the electronic packaging and substrates. Many studies have shown that some polymers filled with high thermal conductivity and low dielectric loss ceramics are suitable for electronic packaging for device encapsulation. Until now, extensive attentions have been paid to the preparation of polymeric composites with high thermal conductivity and low dielectric loss for the application in electronic packaging. In contrast, the thermal conductivities of these dielectric materials are still not high enough and that might restrict their serviceable range. Herein, we briefly reviewed recent progress in this field and introduced a kind of novel composites with surface insulation modified metal aluminum cores to form multilayer coating structures as fillers in polyimide matrix for electronic applications. This structure can significantly improve the thermal conductivity and dielectric properties of composites and give some insights into the effects of modified fillers of composite materials. Such multilayer core–shell structures should have great potentials for the improvement of nanoparticle-based fillers and applications of electronic packaging. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
84 citations
TL;DR: In this article, the contract grant number of the University of Algiers (UBE) was assigned to a contract grant sponsor named Generalitat Valenciana (GV) with a contract number of E-03720130015.
Abstract: National Assessment and Planning Committee of the University Research (CNEPRU); contract grant number: E-03720130015; contract grant sponsor: MINECO; contract grant number: MAT2013-42007-P; contract grant sponsor: Generalitat Valenciana; contract grant number: PROMETEO2013/038; contract grant sponsor: Directorate General of Scientific Research and Technological Development (DGRSDT) of Algeria.
78 citations
TL;DR: In this paper, the effect of aging and additional modifiers on the structure and rheological behavior of SBS modified (SM) asphalt was displayed by adopting various Rheological tests.
Abstract: High viscosity modified (HVM) asphalt was prepared by the addition of styrene-butadiene-styrene (SBS), plasticizer, crosslinker. The effect and proportion of each modifier in the preparation of HVM asphalt were studied. SBS was the major modifier and determined the basic properties of HVM asphalt. Plasticizer (furfural exact oil) and crosslinker (sulfur) as additional modifiers were necessary in improving the workability, stability, and aging resistance of modifier. The effect of aging and additional modifiers on the structure and rheological behavior of SBS modified (SM) asphalt was displayed by adopting various rheological tests. Plasticizer declined the rutting resistance of SM asphalt and increased the viscous behavior of SM asphalt after aging. The use of crosslinker led to the formation of polymer network and improved the aging resistance of SM asphalt. The morphology observation shows crosslinker led to the formation of polymer network and improved the compatibility between SBS and asphalt. Plasticizer prompted the swelling and dispersion of SBS in asphalt and improved the effect of crosslinker further. Aging destroyed the polymer phase seriously and there was still residual polymer phase in asphalt. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
55 citations
TL;DR: This paper presents a meta-analyses of the response of the immune system to the presence of carbon dioxide in response to the treatment of carbon monoxide poisoning.
Abstract: Copyright: 2015. Wiley Online Library. Due to copyright restrictions, only the abstract is available. For access to the full text item, please consult the publisher's website. The definitive version of the work is published in Composites http://onlinelibrary.wiley.com/wol1/doi/10.1002/pc.23718/full
54 citations
TL;DR: In this article, the fabrication and mechanical properties of unidirectional banana/jute hybrid fiber reinforced composites were compared with the single natural fiber reinforced composite and the results showed that the hybrid composite gave encouraging results when compared with individual fiber composites.
Abstract: During the last few years, natural fiber composites are replacing synthetic fiber composites for practical applications due to their advantages like low density, light weight, low cost, biodegradability and high specific mechanical properties. In this connection, the present investigation deals with the fabrication and mechanical properties of unidirectional banana/jute hybrid fiber reinforced composites and compares with the single natural fiber reinforced composites. The physical and mechanical properties of the natural fiber composites were obtained by testing the composite for density, tensile, flexural, inter-laminar shear, impact, and hardness properties. The composite specimens with different weight percentages of fibers were fabricated by using hand lay-up technique and testing were carried out as per ASTM standards. Incorporation of both the fibers into epoxy matrix resulted in an increase in mechanical properties up to 30 wt% of fiber loading. It is found that the hybrid composite give encouraging results when compared with the individual fiber composites. The morphologies of the composites are also studied by scanning electron microscope. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
53 citations
TL;DR: In this paper, the effects of cross-linking ratio on mechanical properties of epoxy-based nanocomposites using molecular dynamics (MD) were investigated and compared with those found in the literature and good agreement was observed between the results.
Abstract: Finite-element method and micromechanical formulations have been used to predict mechanical properties of epoxy-based nanocomposites in recent years. The results of these investigations, however, show large scatters and do not agree well with experimental measurements. The differences in the results may be due to the fact that these approaches do not take some important material parameters into account, such as resin cross-linking ratio, nanotube/matrix interface, and nanotube agglomeration. The main objective of this article is to investigate the effects of resin cross-linking ratio on mechanical properties of epoxy-based nanocomposites using molecular dynamics (MD). First, models of partially cured epoxy resin were created in Materials Studio software to determine resin properties at different cross-linking ratios. Next, one sample of neat epoxy and four samples of nanocomposite with different resin cross-linking ratios were modeled using MD. These models were analyzed using constant strain method to determine mechanical properties of the five samples. Also, the effects of cross-linking ratio on nanocomposite density were investigated. The simulation results show that nanocomposite Young's modulus increases with resin cross-linking ratio. Resin cross-linking ratio, however, did not have a significant effect on nanocomposite density. Further, molecular simulation results were compared with rule of mixtures and Mori–Tanaka predictions. In addition, the results were compared with those found in the literature and good agreement was observed between the results. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers
50 citations
TL;DR: In this paper, the authors present a review of studies on materials, preparation, properties, and characterization of polyvinyl alcohol (PVA) nanocomposite hydrogels.
Abstract: This article presents a review of studies on materials, preparation, properties, and characterization of polyvinyl alcohol (PVA) nanocomposite hydrogels. The structure and properties of Montmorillonite, the nanoclay used in the manufacture of PVA nanocomposites and techniques for making PVA nanocomposite hydrogels have been reviewed. The characterization techniques such as Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), Dynamic mechanical analysis (DMA), Scanning electron microscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) are also studied. The XRD patterns and TEM images have proven the intercalated and exfoliated structures of PVA nanocomposite hydrogels that is due to the presence of nanoclay layers. Investigation of FT-IR spectra shows the bonding formation between OH and silanol groups of PVA and Montmorillonite. Also, the results of DSC and DMA indicated a decrease in crystallinity and the glass transition temperature of PVA by the incorporation of nanoclay, while the loss modulus is increased compared to that of pure PVA. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
49 citations
TL;DR: In this paper, the authors used grinded seashell wastes (SS) as a bio-filler to reinforce acrylonitrile-butadiene-styrene copolymer (ABS).
Abstract: The seashell is mainly composed of calcium carbonate and organic materials which, when decompose, produce harmful gases with significant odor and toxicity. Therefore, their wastes are considered to be a problem and could be hazardous to human. To overcome this problem, this study proposed to use grinded seashell wastes (SS) as a bio-filler to reinforce acrylonitrile–butadiene–styrene copolymer (ABS). Commercial calcium carbonate, CaCO3 (CC) was also used to compare the results. The filler and their composites were characterized by X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Dynamic Mechanical Analysis (DMA), Thermogravimetric Analysis (TGA), and Cone Calorimeter. DMA data show that the addition of low amounts of seashell bio-filler to ABS increases the storage modulus (E′). The glass transition temperature (Tg) values are shifted to higher temperature. On the other hand, the ABS/SS composite shows a higher tensile strength than CC filled ABS. TGA results exhibit that there is an enhancement in the thermal stability when calcium carbonate from seashell is added. Good flame retardant properties were achieved with increasing the bio-filler content. According to XRD and FT-IR results of the char residues after cone calorimetric tests, the compact char layer acts as a barrier to oxygen and heat transfer, preventing the escape of polymer fragments to the gas phase, and decreasing the heat release rate during combustion. POLYM. COMPOS., 38:2788–2797, 2017. © 2015 Society of Plastics Engineers
48 citations
TL;DR: In this article, two sets of jute epoxy composites are fabricated by varying first fiber loading from 10 to 50 wt% at an interval of 10 wt%, and then granite powder incorporated from 0 to 24 wt%.
Abstract: In the present study, two sets of jute epoxy composites are fabricated by varying first fiber loading from 10 to 50 wt% at an interval of 10 wt% and then granite powder incorporated from 0 to 24 wt% in an interval of 8 wt% in the composites. The initial study is to prepare polymeric composites for wind turbine blade application and study the following physical to thermo-mechanical properties including fracture toughness of the composites. The void content of the unfilled composites show in decreasing order (from 6.37 to 3.07%) with the increasing in fiber loading which satisfied well with the increasing in tensile strength from 28.33 to 34.2 MPa and flexural strength from 44.2 to 97.8 MPa, respectively. As far as particulate filled composites the void content shows reverse in trend (from 2.99% to 9.68%) with the increasing in filler content and which justifies the mechanical properties i.e tensile strength decreases from 33.72 to 32.27 MPa and similarly in case of flexural strength also. Whereas, hardness shows a unique behavior both in fiber reinforced and particulate filled composites in an increasing order from 29 to 44 Hv, respectively. Fracture toughness is observed to be constant for all considered crack lengths however, its value significantly improved with both type of reinforcement. The dynamic mechanical analysis shows positive effect of both the reinforcement for mechanical performance under cyclic stresses. Finally, Cole–Cole plot is drawn from the dynamic mechanical analysis results to verify the homogeneity of the composites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
48 citations
TL;DR: In this paper, the authors adopt an analytical approach to study the dielectric relaxation and ac conductivity behavior of polyvinyl alcohol (PVA)-CdSe nanocomposite films in the frequency range 100 Hz to 1 MHz and in the temperature range 298 K to 420 K.
Abstract: We adopt an analytical approach to study the dielectric relaxation and ac conductivity behavior of the polyvinyl alcohol (PVA) - Cadmium Selenide (CdSe) nanocomposite films in the frequency range 100 Hz ≤ f ≤ 1 MHz and in the temperature range 298 K ≤ T ≤ 420 K. The CdSe nanoparticles are synthesized via a simple wet chemical route and are then impregnated into the polyvinyl alcohol matrix by 0.5 wt%, 1 wt%, and 4 wt%. About 1.7 times increase in effective permittivity (at 100 KHz) for the 4 wt% nanoparticle impregnated sample is observed from the analysis of the dielectric reinforcement function, which is attributed to the occurrence of interfacial polarization. It is found that the Cole-Cole model with a dc conductivity correction term can well fit the permittivity data. We have found that the dielectric relaxation time increases with increase in nanoinclusion into the matrix but decreases with increase in temperature. However, the space charge carrier conductivity and free charge carrier conductivity increase either with increase in nano inclusions or with increase in temperature. AC conductivity behavior have been analyzed considering the Jonscher power law and Dyre's random free energy barrier model, which reveals lowering of the maximum barrier height and correlated barrier hopping as the prevalent charge transport mechanism for the nanocomposites. Electric modulus study indicates similar conductivity relaxation dynamics for the nanocomposites but the responses deviate appreciably from the simulated ideal Debye responses. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this article, a comprehensive review about surfacetreatments as well as the most recent developments ofcassava polymer/fiber based bio-composites and the summary of main result presented in the literature, focusing on properties of cassava composite andapplications.
Abstract: Cassava is a type of plant which has different pur-poses of use. It is used to produce various foods, bio-fibers, bio-composites, and bio-polymers. Besides, it isnow used as renewable energy source of starch. Theintention of the paper is to focus on the importance ofcassava fibers, polymers, and composites as well asits potential applications, another focus point of thisresearch is the biodegradable polymer developmentwhich is taken out from cassava starch. Moreover, thiswork gives a comprehensive review about surfacetreatments as well as the most recent developments ofcassava polymer/fiber based bio-composites and thesummary of main result presented in the literature,focusing on properties of cassava composite andapplications. These applications were related to vari-ous industrial application as well as others such as theproduction of xylenes, ethanol and bio-fuel, food, foodpackaging and cassava foam. POLYM. COMPOS.,00:000–000, 2015.
TL;DR: In this article, the impact strength, tensile strength, flexural strength, and thermal stability of poly(lactic acid) (PLA) composites were improved by incorporating poly(butylene succinate) (PBS) and wood flour (WF).
Abstract: This work sought to improve the toughness and thermal stability of poly(lactic acid) (PLA) by incorporating poly(butylene succinate) (PBS) and wood flour (WF). The PLA/PBS blends showed a PBS-dose-dependent increase in the impact strength, elongation at break, degree of crystallinity, and thermal stability compared to the PLA, but the tensile strength, Young's modulus, and flexural strength were all decreased with increasing PBS content. Based on the optimum impact strength and elongation at break, the 70/30 (w/w) PLA/PBS blend was selected for preparing composites with five loadings of WF (5–30 phr). The impact strength, tensile strength, flexural strength, and thermal stability of the PLA/PBS/WF composites decreased with increasing WF content, and the degree of crystallinity was slightly increased compared to the 70/30 (w/w) PLA/PBS blend. Based on differential scanning calorimetry, the inclusion of PBS and WF into PLA did not significantly change the glass transition and melting temperatures of PLA in the PLA/PBS blends and PLA/PBS/WF composites. From the observed cold crystallization temperature of PLA in the samples, it was evident that the degree of crystallinity of PLA in all the blends and composites was higher than that of PLA. The PLA/PBS blend and PLA/PBS/WF composite degraded faster than PLA during three months in natural soil, which was due to the fast degradation rate of PBS. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers
TL;DR: In this article, a biodegradable oxygen scavenger system, which consists of α-tocopherol-loaded poly(lactic)acid microparticles containing 40 wt% of the natural antioxidant agent, was prepared by an oil in water (O/W) emulsion-solvent evaporation method.
Abstract: In this work, a biodegradable oxygen scavenger system, which consists of α-tocopherol-loaded poly(lactic)acid microparticles containing 40 wt% of the natural antioxidant agent, was prepared by an oil in water (O/W) emulsion-solvent evaporation method. The preparation procedure assured high encapsulation efficiency and production yield and gives no noticeable alteration of the molecular structure of the microencapsulated active α-tocopherol, as demonstrated by Fourier-transform infrared and thermogravimetric analyses measurements. The produced active microparticles are semicrystalline and are characterized by suitable morphology (size and shape) to have satisfactory flowability to be used as active powder additive in conventional polymer extrusion technologies. Both the scavenging capacity and rate are in line with the values required for an effective oxygen scavenger system. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this article, a novel composite material was fabricated using conventional resin matrix consisting of Bisphenol-A glycidyl methacrylate (Bis-GMA), tri-ethylene glycol dimethacrylated (TEGDMA), camphorquinone (CQ), and ethyl 4 dimethyl amino benzoate (EDMAB).
Abstract: Gypsum has been recognized as acceptable for human consumption as a dietary source of calcium. During contact with teeth, it releases Ca2+ ions needed for remineralization of tooth tissue, and therefore based on the concept of remineralization, gypsum may be a strategic additive for dental restorative materials. Hence, the objective of this study was to develop and characterize a novel dental material reinforced with different weight fraction of micro sized gypsum filler particle. A novel composite material was fabricated using conventional resin matrix consisting of Bisphenol-A glycidyl methacrylate (Bis-GMA), tri-ethylene glycol dimethacrylate (TEGDMA), camphorquinone (CQ) and ethyl 4 dimethyl amino benzoate (EDMAB). Four different compositions were prepared by reinforcing different weight percentage (0–3 wt%) of silane functionalized micro sized gypsum particle. Fourier Transformed Infrared spectroscopy (FT-IR), Transmission Electron Microscope (TEM) and Thermogravimetric Analysis (TGA) of silane treated filler were used to study the coupling phenomena between filler and resin. Polymerization shrinkage of composites was evaluated using specific gravity method. The Dynamic Mechanical Analysis (DMA) result revealed that the Glass transition temperature was found to be decreased by 15°C compared to unfilled composite. It was also found that the 2 wt% gypsum content recorded the highest value of storage modulus. Simultaneous Thermal Analysis (STA) result revealed that 2 wt% gypsum filled dental composite exhibited maximum thermal stability. The novel dental material exhibited better physical, optical, mechanical, thermal properties and lowest polymerization shrinkage with maximum conversion. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this paper, a strong and tough carbon nanotube (CNT)/epoxy composite was fabricated by resin solution impregnation process based on floating catalyst chemical vapor deposition (CVD) growth CNT films, which had a tensile strength and toughness of 405 MPa and 122 J/g, respectively, and good damping properties as well.
Abstract: A strong and tough carbon nanotube (CNT)/epoxy composite was fabricated by resin solution impregnation process based on floating catalyst chemical vapor deposition (CVD)–growth CNT films, which had a tensile strength and toughness of 405 MPa and 122 J/g, respectively, and good damping properties as well. Evolution of the composite structure revealed that the CNTs aligned along the tension direction with decreasing orientation angle, and the CNT bundle size enlarged during the tensile test process, which contributed to efficient load transfer among the composite network. Results showed that the proper resin content could bring benefit for strong connections and dense packing of CNTs/bundles, but excessive resin content was unfavorable for improving mechanical properties and conductivities of the nanocomposite. In addition, the resin in CNT film/epoxy composites had a lower crosslink density than that in a neat epoxy system, which endowed the CNT composites with large deformation capability. POLYM. COMPOS., 38:588–596, 2017. © 2015 Society of Plastics Engineers
TL;DR: In this paper, a new type of nanocomposites based on a high performance bisphenol-A phthalonitrile resin and surface-modified alumina nanoparticles was prepared by a hot compression molding technique.
Abstract: A new type of nanocomposites based on a high performance bisphenol-A phthalonitrile resin and surface-modified alumina nanoparticles was prepared by a hot compression molding technique. The effect of adding different amounts of the reinforcing phase on the thermal and mechanical properties of the resulting nanocomposites was investigated. Thermogravimetric analysis showed that the starting decomposition temperatures and the residual weight at 800°C were highly improved upon adding the nanofillers. At 15 wt% nanoloading, the glass transition temperature and the storage modulus were considerably enhanced, reaching 346°C and 3.4 GPa, respectively. The tensile strength and modulus as well as the microhardness values increased with the increasing amount of the nanoparticles. The tensile modulus calculations were investigated using Series, Halpin-Tsai, and Kerner models. Haplin-Tsai model was found to reproduce the experimental data with the best accuracy. Estimation of the nanofillers shape factors for both Haplin-Tsai and Kerner models significantly improved the precision of the cited predictive models. The fractured surface of the nanocomposites analyzed by SEM exhibited homogeneous and rougher surfaces compared to that of the pristine resin. Finally, this new kind of nanocomposites is a highly attractive candidate for use in advanced technological applications such as the aerospace and military fields.POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this paper, the surface topographies of carbon fibers treated by sizing agents with different graphene oxide (GO) content were investigated by scanning electron microscopy and the surface elements compositions of carbon fiber were determined by X-ray photoelectron spectrometer.
Abstract: The surface topographies of carbon fibers treated by sizing agents with different graphene oxide (GO) content were investigated by scanning electron microscopy. The surface elements compositions of carbon fibers were determined by X-ray photoelectron spectrometer. The interfacial properties of composites were studied by interfacial shear strength. The thermo-mechanical properties of two typical specimens (CF-G0 and CF-G1 composites) were investigated by dynamic mechanical thermal analysis. The results showed the introduction of GO sheets on carbon fibers surfaces effectively improved the mechanical properties of carbon fibers/epoxy composites. POLYM. COMPOS., 38:2425–2432, 2017. © 2016 Society of Plastics Engineers
TL;DR: In this paper, the authors explore the validation of impact behavior in CNT-based FRP composite by LS-DYNA and present study of variation in impact behavior by varying CNT percentage in composite laminates.
Abstract: In last 2 decades use of CNT based-Fiber Reinforced Polymer (FRP) Composite have revolutionized the aerospace, automobile, marine industry as it have showed exceptional mechanical properties like impact resistant, high energy absorbing capacities, damping properties, etc. The goal of this review is to explore the validation of impact behavior in CNT based FRP composite by LS-DYNA. Impact behavior depends upon various parameters like velocity of impact, shape of impactor and its weight, environmental conditions as temperature dependency, contact time and damage area and many other considerations. Prediction of impact damage is done using methods like absorbed energy, gross damage produced and/or micro energy dissipation. This article also presents study of variation in impact behavior by varying CNT percentage in composite laminates. POLYM. COMPOS., 2014. © 2014 Society of Plastics Engineers
TL;DR: In this article, an unsaturated polyester resins (UPe)-based nanocomposites and fumed silica Aerosil R812S, R805 and R816, and R200 modified with phenyl terminal group, R200NPh, were prepared.
Abstract: Unsaturated polyester resin (UPe)-based nanocomposites and fumed silica Aerosil R812S, R805 and R816, and R200 modified with phenyl terminal group, R200NPh, were prepared. UPe resins were synthesized from maleic anhydride and products of glycolysis, obtained by polyethylene terephthalate depolymerization with dipropylene glycol in the presence of tetrabutyl titanate catalyst. The obtained unsaturated polyesters were characterized by acid, hydroxyl, and iodine values and by FTIR and NMR analysis. The microstructural analysis of the prepared nanocomposites, performed by using transmission electron microscopy, confirmed that silica nanoparticles formed chain-like aggregates in the polymer matrix. The presence of modified silica nanoparticles had no influence on the glass transition temperature and thermal stability of polyester matrix. The tensile modulus, stress at break, and hardness of cured products increased with increasing silica content. The impact strength of cured samples was not influenced by the silica content. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this article, the authors investigated the underlying mechanism for selective localization of graphene oxides in PLA/EVA blends and found that rGOs are located at the interface when the blend nanocomposites were prepared from PLA masterbatch.
Abstract: Cocontinuous PLA/EVA (60/40 wt%) blends were filled with reduced graphene oxides (0.1–3 wt%) through the master batches of PLA/rGOs and EVA/rGOs, respectively. The results show that rGOs are located at the interface when the blend nanocomposites were prepared from PLA masterbatch. On the other hand, rGOs are located in EVA component when the blend nanocomposites were prepared from EVA/rGOs materbatch. The underlying mechanism for selective localization of rGOs in PLA/EVA was systematically investigated. First, theoretical prediction indicates the interface energies between two polymer components and rGOs are similar and rGOs prefer to locate at the interface of blend. Therefore, kinetic effects, including interfacial stability of rGOs and viscoelastic properties of polymer, play an important role on the selective localization of rGOs migration. Finally, The electrical resistivity measurements show that nanocomposites with rGOs locating at the interface is endowed much lower resistivity and percolation threshold compared to the blend nanocomposites with rGOs locating at EVA component. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this article, the physical and mechanical properties of polyamide-6 (PA6)/nitrile butadiene rubber (NBR) thermoplastic elastomers (TPEs) reinforced with pristine and organosilane modified halloysite nanotubes (HNTs) were investigated.
Abstract: Microstructure and mechanical properties of nanocomposites were studied for polyamide-6 (PA6)/nitrile butadiene rubber (NBR) thermoplastic elastomers (TPEs) reinforced with pristine and organosilane modified halloysite nanotubes (HNT). Organosilane modification of the nanotubes was done to enhance the interfacial interactions and therefore to achieve TPE nanocomposites with more fine morphology of the NBR phase and better controlled mechanical properties. The effects of rubber content, HNT loading and modification of HNT on the morphology and mechanical properties were investigated. The nanocomposites and HNTs modified with [3-(2,3-Epoxypropoxy)-propyl]-trimethoxysilane were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning colorimeter (DSC). The morphology study of prepared nanocomposites show that the size of NBR droplets in TPE nanocomposites reduces by introducing of pristine and organosilane modified halloysite nanotubes into the PA6 phase. The mechanical properties investigations revealed that the Young's modulus increases up to 45 and 75% by introducing of pristine and modified HNTs into the PA6 phase respectively. The results show that significant improvement was achieved in the physical and mechanical properties of PA6/NBR thermoplastic elastomer nanocomposites containing of silane modified HNTs. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers
TL;DR: In this paper, the preparation and mechanical characterization of green composites using polylactic acid (PLA) matrix including chicken feather fiber (CFF) as reinforcement was described, and the results indicated that these types of composites can be used for various applications.
Abstract: Green composites, a bio-based polymer matrix is reinforced by natural fibers, are special class of bio-composites. Interest about green composites is continuously growing because they are environment-friendly. This study describes the preparation and mechanical characterization of green composites using polylactic acid (PLA) matrix including chicken feather fiber (CFF) as reinforcement. Extrusion and an injection molding process were used to prepare CFF/PLA composites at a controlled temperature range. CFF/PLA composites with fiber mass content of 2%, 5%, and 10% were manufactured. The effects of fiber concentration and fiber length on mechanical properties of CFF/PLA composites have been studied. Mechanical properties of composites were investigated by tensile, compression, bending, hardness, and Izod impact testing. The results of experiments indicated that Young's modulus, compressive strength, flexural modulus, and hardness of the PLA reinforced CFF composites are higher but tensile strength, elongation at break, bending strength and impact strength of them are lower than pure PLA. The results indicate that these types of composites can be used for various applications. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this paper, a comprehensive characterization of wettability and interfacial properties of kenaf fibers and its unsaturated polyester composites fabricated by resin transfer molding (RTM) is presented.
Abstract: This paper reports on comprehensive characterization of wettability and interfacial properties of kenaf fibers (KF) and its unsaturated polyester (UPR) composites fabricated by resin transfer molding (RTM). KF were chemically modified by immersing in 6% NaOH concentration for 1, 2, 3, 4, and 5 h to enhance the interaction between KF and UPR. FTIR spectral data showed the chemical changes in KF after treatment which induced the modification of physical and wettability characteristics of KF. The changes in crystalinity index (CrI) and thermal stability of KF content were analyzed using X-ray diffraction (XRD) and thermogravimetry (TGA) techniques, respectively. Scanning electron microscope (SEM) shows a cleaner KF surface upon KF treatment and atomic force microscopy (AFM) signify an increasing in available fiber–matrix specific contact area. Wettability of KF was investigated by means of surface energy measurement using Washburn contact angle principle via Owens–Wendt–Rabel–Kaelble (OWRK) method. Surface energy was found to increase with longer soaking time. The effect of soaking time of alkaline treatment in enhancing the interface bonding characteristic between the KF and UPR matrices can be reflected by the ILSS value of the composites. The highest value of ILSS was recorded by 3 h treated KF composite. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this article, multi-walled carbon nanotubes (MWCNTs) filled graphite-lubricated phenolic-based friction composites reinforced with combination of lapinus/Kevlar fibers have been fabricated and subsequently evaluated for their dynamic-mechanical and tribological properties.
Abstract: Multi-walled carbon nanotubes (MWCNTs) filled graphite lubricated phenolic-based friction composites reinforced with combination of lapinus/Kevlar fibers have been fabricated and subsequently evaluated for their dynamic-mechanical and tribological properties. The experimental results indicated that the higher MWCNT content enhances the thermal stability, whereas, lower MWCNT content enhances the thermo-mechanical properties of the friction composites. The tribo-performance evaluation has revealed that with the increase in MWCNT content, the friction-fade and friction-recovery performances are enhanced. The friction-stability and friction-variability coefficients are influenced by the combination of MWCNT, graphite, lapinus, and Kevlar constituents. The wear performance decreases with the increase in lapinus and MWCNT, whereas, it increases when the amount of Kevlar or graphite is increased in the composites. Wear surface morphological studies have led to the qualitative characterization of the topographical attributes and the nature of the frictional contact patches which is crucial in understanding the role of MWCNT on friction and wear mechanisms of the investigated automotive brake friction materials. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this article, a series of five Al-Si/PBI composite (ASPBI) membranes were developed and characterized for application in high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs).
Abstract: In this work, Al–Si was synthesized via a sol–gel process and introduced in poly 2,2′-m-(phenylene)-5,5′-bibenzimidazole (PBI). As a result, a series of five Al–Si/PBI composite (ASPBI) membranes (0, 3, 6, 9, and 12 wt%) were developed and characterized for application in high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). The chemical and morphological structure of ASPBI membranes were analyzed by Fourier transform infrared spectroscopy, X-ray diffractometer, and scanning electron microscopy. According to the doping level test and thermogravimetric analysis, as the concentration of Al–Si increased, the doping level increased up to 475% due to the affinity and interaction between Al and phosphoric acid (PA). Moreover, the proton conductivity, current density at 0.6 V, and maximum power density of ASPBI membranes increased up to 0.31 S cm−1, 0.320 A cm−2, and 0.370 W cm−2, respectively, because the increased concentration of Al–Si allows the membranes to hold more PA. Alternatively, as the amount of Al–Si increased, the tensile strength of PA-doped and -undoped membranes decreased. This was caused by both excess PA and aggregation, which can cause serious degradation of the membrane and induce cracks. Furthermore, the PA-doped and -undoped ASPBI12 had the lowest tensile strength of 11.6 and 77.2 MPa. The improved proton conductivity and single cell performance of ASPBI membranes implies that these membranes are possible candidates for HT-PEMFC applications. However, further studies seeking to enhance the compatibility between PBI and Al–Si and optimize the amount of filler should be performed. POLYM. COMPOS., 38:87–95, 2017. © 2015 Society of Plastics Engineers
TL;DR: In this paper, the free vibration and resonance of finite length functionally graded (FG) nanocomposite cylinders are investigated by a mesh-free method, where three linear types of FG distributions and a uniform distribution of wavy carbon nanotubes (CNTs) are considered along the radial direction of axisymmetric cylinder.
Abstract: In this article, free vibration and resonance of finite length functionally graded (FG) nanocomposite cylinders are investigated by a mesh-free method. These cylinders are reinforced by wavy single-walled carbon nanotubes (SWCNTs) and subjected to a periodic internal pressure. Three linear types of FG distributions and a uniform distribution of wavy carbon nanotubes (CNTs) are considered along the radial direction of axisymmetric cylinder. The mechanical properties are simulated using a micromechanical model in volume fraction form. In the mesh-free analysis, moving least squares shape functions are used for approximation of displacement field in the weak form of motion equation and the transformation method is used for imposition of essential boundary conditions. Effects of geometric dimensions, boundary conditions and also, waviness index, aspect ratio, volume fraction, and distribution pattern of CNTs are investigated on the natural frequencies and resonance behaviors of FG carbon nanotube reinforced composite (CNTRC) cylinders. It is observed that CNT waviness has a significant effect on the vibrational behavior of the CNTRC cylinders. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers
TL;DR: In this paper, a novel phosphorous-nitrogen intumescent flame retardant with reactive diamino groups, benzoguanamine spirocyclic pentaerythritol bisphosphonate (BSPB), was synthesized and used as a chain extender, and then a series of flame-resilient waterborne polyurethanes (FRWPU) were prepared by covalently conjugating the BSPB into WPU backbone.
Abstract: A novel phosphorous-nitrogen intumescent flame retardant with reactive diamino groups, benzoguanamine spirocyclic pentaerythritol bisphosphonate (BSPB), was synthesized and used as a chain extender, and then a series of flame retardant waterborne polyurethanes (FRWPU) were prepared by covalently conjugating the BSPB into waterborne polyurethane (WPU) backbone. Their structures were characterized by Fourier transformed infrared spectrometry (FTIR), 1H and 31P nuclear magnetic resonances (NMR), respectively. Simultaneously, the flame retardancy and the thermal stability of FRWPU were systematically investigated by limiting oxygen index (LOI) test, UL-94 vertical burning test and thermogravimetric analysis (TGA). The results indicated that with the increase of BSPB content from 0 to 8 wt%, the LOI value of FRWPU increased from 18.6 to 27.3%, showing significant improvement by 8.7%. Compared with WPU, FRWPU showed decreased thermal stability but promoted char residue ratio. Conjugation of BSPB could obviously enhance the mechanical properties of FRWPU, the Young's modulus and tensile strength dramatically increased with the increase of BSPB. Investigation of char forming mechanism of BSPB through real time Fourier transform infrared spectra (RTFTIR) and scanning electronic microscopy (SEM) revealed that the polyphosphoric acid and phosphorus oxynitrides rich outer intumescent char layer could form protective shields to inhibit effectively internal polyurethane to heat and flame diffusion during contacting fire. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this paper, a new method to generate the random fiber distribution in transverse cross-section of fiber reinforced composites with a desired high fiber volume fraction is presented, combined with random disturbance algorithm and perfect elastic collision algorithm, which can study the continuous changing trends of both statistical characterizations and mechanical properties of the RVE models from periodic distribution to random distribution.
Abstract: This article presents a new method to generate the random fiber distribution in transverse cross-section of fiber reinforced composites with a desired high fiber volume fraction. The method, combined with random disturbance algorithm and perfect elastic collision algorithm, generates the Representative Volume Element (RVE) models through shifting fibers and avoiding fibers overlapped. The advantage of this algorithm is that it can study the continuous changing trends of both statistical characterizations and mechanical properties of the RVE models from periodic distribution to random distribution. Through analysis with compare, the generated distribution models present a convergence state after a designated disturbance time whether the initial periodic distribution is rectangular or hexagonal. We find that the transverse tensile moduli of rectangular model are higher than the random model while the hexagonal model is on the contrary. The transverse shear modulus of random model is higher than rectangular model and close to hexagonal model. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
TL;DR: In this paper, the authors have focused on developing cellulose nanofibers (CNFs)/polylactic acid (PLA) coated with ethanolic extract of propolis (EEP).
Abstract: This work has focused on developing cellulose nanofibers (CNFs)/polylactic acid (PLA) coated with ethanolic extract of propolis (EEP). First, the chemical composition of EEP was studied in order to determine the major compounds. Composites were then prepared using solvent casting method, with the goal of making green composites. The effectiveness of EEP was evaluated for its antibacterial and antifungal properties, using standard protocol of disc diffusion method (DDM). Chemical analysis of EEP indicated that the propolis samples had high concentrations of the aromatic acids, phenolics, esters, and other derivatives, which are responsible for the antibacterial and antifungal properties of propolis. Experimental results indicated that EEP had a considerable antibacterial activity against most of tested pathogen strains. In general, the surface of modified CNFs/PLA films showed antibacterial activity against Gram-positive bacteria, even at very low concentrations of EEP. The addition of EEP to the tested films drastically increased the antibacterial effect against Gram-positive, such as Bacillus anthracis, Staphylococcus aureus, and Salmonella enteric, while there was no effect on Gram-negative bacteria. Moreover, the results pointed out the inhibitory action of EEP on Candida albicans. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers