bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Scale Modelling of Long-Term Mechanical Behaviour in Polymer Composite Laminates with Woven Fibre Architecture
Authors: Gupta V. , Roy S. , Dharani L. R.
Published: September 2018

A comprehensive analytical model for predicting the long-term durability of polymers and polymer matrix composites should in general take into account polymer viscoelastic/viscoplastic creep, hygrothermal effects, and the effects of physical and chemical ageing on material response. These effects, in turn are influenced by a multitude of factors such as polymer morphology, service temperature, ambient relative humidity, internal moisture concentrations, stacking sequence, fibre volume fraction, fibre architecture, applied stress level, degree of damage and ageing time. The primary objective of this paper is to present a multi-scale modelling methodology to simulate the long-term interlaminar properties in polymer matrix woven composites and then predict the critical regions where failure is most likely to occur.

A micro-mechanics approach towards modelling the out-of-plane viscoelastic behaviour of a five-harness satin woven-fibre cross-ply composite laminate is presented, taking into consideration the weave architecture and time-dependent effects. In-plane properties are assumed to be dominated by the carbon fibres and are hence deemed elastic. The classical lamination theory model proposed by Raju and Wang is adapted to include the in-plane elastic behaviour of woven fibre composites. For the matrixdominated out-of-plane response, a viscoelastic creep model is employed to model the resin, based on Schapery's nonlinear viscoelastic constitutive law. In addition, physical ageing of the matrix has been included in the model, using the effective time theory proposed by Struik. Furthermore, the effect of large deflections and rotations on the time dependent out-of-plane behaviour is also investigated using the micro-mechanics model. The homogenized in-plane and out-of-plane compliance obtained using the proposed micro-mechanics methodology could be applied within the framework of a structural finite element code to model the macro-scale long-term behaviour of a woven fabric composite structure.
Particle Motion and Segregation in Piston Driven Free Surface Flows of Viscoelastic Fluids
Authors: Ogadhoh Shem O. , Papathanasiou T.D.
Published: September 2018

We have investigated the motion, redistribution and segregation of solid particles dispersed in a viscoelastic fluid during piston-driven free surface flows. This phenomenon and its effect on suspension microstructure is of significant importance in a number of processes used to form composite materials, notably injection and compression moulding. In the experimental part of this study we used a 5% w/w suspension of PMMA particles dispersed in a hydrated hydroxypropyl guar gel. A reversible motor with variable speed and minimal vibration was used to move a tube up and down on a stationary piston, creating a piston-driven flow with a free surface. We observed that the particles move away from the piston and towards the free surface where they slowly accumulate. This observation confirms theoretical predictions that in the presence of a normal stress gradient perpendicular to the direction of bulk flow, as would be observed with viscoelastic fluids, suspended particles tend to gravitate towards and then remain near the free surface. Simulations show that the speed of this segregation increases with fluid elasticity, shear rate and particle size, in agreement with literature models for the lateral migration velocity of particles in viscoelastic fluids.
Use of Post-Life Waste and Production Waste in Thermoplastic Polymer Compositions
Authors: Kowalska Ewa , Wielgosz Zbigniew , Pelka Janina
Published: September 2018

Voluminous post-life waste and production waste pose the paramount environmental problem of our times. One major problem is how to reuse post-life waste: spent plastics, rubber scrap, worn-out automobile tyres, waste paper and production waste; wood pulp or powder and particularly the waste arising in the production of fertiliser, phosphogypsum. We have been studying the re-use of these wastes as blends with virgin and recycled polymers. These novel polymer compositions can be used to make:

• porous pipes intended for irrigation or fertilization.

• vehicle parts in the automobile industry

• tiles or flooring in the building industry

• road safety and traffic control equipment

• sound-absorbing screens along motorways

• packing in biological wastewater treatment

• biodegradable flower pots, buckets, fence elements and similar profiles.
High Yield Synthesis of Fluorinated Benzoxazine Monomers and Their Molecular Characterization
Authors: Liu Jingping , Ishida Hatsuo
Published: September 2018

A method for the synthesis of 3,4-dihydro-3-pentafluorophenyl-2H-1,3-benzoxazine in a high yield derived from pentafluoroaniline is described. This fluorinated benzoxazine monomer has been developed as a potential precursor for a polybenzoxazine in electronic applications as well as others taking advantage of the low dielectric constant, low flammability, low refractive index, low coefficient of friction, and high glass transition temperature of fluorinated compounds. The traditional benzoxazine synthesis conditions are inappropriate for the synthesis of fluorinated benzoxazines when the fluorination is on the primary amine component. It is found that the pH value of the reaction medium is the controlling factor in the yield of the compound from weak amines. A strongly acidic condition is necessary for the synthesis of similar compounds from other very weak amines having a pKa lower than 3. A dramatic increase in the yield of benzoxazine ring has been observed when benzoxazines with very weak amines are synthesized in an acidic medium. The effects of solvent and pKa of phenol are also discussed. The synthesized compounds have been characterized by 1H NMR, FTIR, GPC and HPLC.
Improved Storage Stability of LDPE/SBS Blends Modified Asphalts
Authors: Gao Guangtao , Zhang Yong , Zhang Yinxi , Sun Kang , Fan Yongzhong
Published: September 2018

In this paper, Low Density Polyethylene (LDPE) / Styrene-Butadiene-Styrene (SBS) blends prepared under high shear stress were used as asphalt modifiers. Compared to the asphalts modified by LDPE and SBS added directly, the blend modified asphalts showed much better storage stability in the presence of sulfur at high temperature. No visible phase separation was observed under an optical microscope at high temperature and the morphology analysis indicated that the phase structure of the LDPE/SBS blend modified asphalts was unchanged with time at high temperature. After storage at 163°Ê for 48h, the LDPE/SBS blend modified asphalts had no evidence of coalescence of polymer particles. The rheological properties of the asphalts were also improved by the addition of polymers in all cases.
Nonlinear Viscoelasticity of Silicone Carbide Whisker-Filled Liquid Crystalline Polymer Melts
Authors: Katsuhiko Araki , Takeshi Kitano , Takahiro Tanegashima , Anezka Lengalova , Petr Saha
Published: September 2018

Dynamic viscoelasticity of melts of semi-aromatic liquid crystalline polymer (LCP) and its silicone carbide (SiC) whisker-filled compounds was measured to analyze quantitatively their nonlinear viscoelastic properties by Fourier expansion of the shear stress wave. For LCP the tertiary terms, G'3 and G″3, are considerably smaller than their primary terms, G'1 and G″1, i.e. their viscoelasticity is almost linear. Viscoelastic behaviour of the silicone carbide whisker-filled LCP system was compared with that of the carbon fiber (CF)- and glass fiber (GF)-filled LCP systems presented in [18]. The CF/LCP system shows a dependence of the oscillatory angle upon its G'i and G″i, making both accordingly decrease with increasing i from 1 to 3 and 5. The G'3 and G″3 values of the polymer system, compared to its G'1 and G″1 counterparts, are sufficiently large not to be negligible, suggesting that the system's viscoelasticity is nonlinear.

Furthermore, the SiC whisker-filled LCP system was examined for the dependence of the ratios G'i/G'1 and G″i/G″1 (i = 3, 5), and Gi/G1 (i = 3, 5, 7) as indicators of the degree of viscoelastic nonlinearity upon angular frequency. The results did not show any significant difference between G'3/G'1 and G'5/G'1 values, or between G″3/G″1 and G″5/G″1 values. The ratio Gi/G1 (i = 3, 5, 7), representing the nonlinearity of viscoelasticity of the system, however, is higher with an increase in the oscillatory angle.
Influence of Maleation of Ground Rubber Tyre (GRT) on the Thermorheological behaviour of Thermoplastic Elastomers Based on Ethylene Propylene Diene Rubber, GRT and Ethylene-co-acrylic acid
Authors: Naskar Amit K. , De S. K. , Bhowmick Anil K.
Published: September 2018

The thermorheological behaviour of thermoplastic elastomeric blends based on both ground rubber tyre (GRT) and maleic anhydride grafted GRT (m-GRT) has been studied. The blend composition based on m-GRT exhibits a higher melt viscosity than the corresponding control blend based on GRT. The former exhibits lower die swell and less melt fracture at low shear rates than the latter, when extruded at 180°C through a capillary rheometer. At high shear rates, however, both the blends exhibit melt fracture. There is apparently some interaction between m-GRT and the matrix, which is evident from dynamic mechanical analysis. The m-GRT causes a significant lowering in tanδ at temperatures higher than the Tg of the blend.
Recycling of Glass Fibre Reinforced Phenolic Prepreg Waste Part 1. Recovery and Reuse of Glass Fibres in PP and PA6
Authors: Gröning Mikael , Hakkarainen Minna , Albertsson Ann-Christine
Published: September 2018

The present paper describes a feasible process to reuse glass fibres separated from phenolic prepreg waste as reinforcing filler in polypropylene (PP) and polyamide 6 (PA6). Prior to compounding, the recovered glass fibres were cut into 50 mm long fibre bundles and surface treated with gamma-aminopropyltriethoxysilane (APS) for increased composite interfacial strength. Electron Spectroscopy for Chemical Analysis (ESCA) and Atomic Force Microscopy (AFM) showed that the silane coupling agent was attached to the surface of the glass fibres but the silane layer was somewhat uneven, probably due to the presence of small amounts of organic contaminants. In addition it was found necessary to clean the glass fibres from organic contaminants by thermal treatment in order to attach silane coupling agent to the surfaces. The tensile strengths obtained for PP and PA6 composites with 30 wt% filler level of surface treated recovered glass fibres were 49 MPa and 101 MPa, respectively. This should be compared to 30 MPa and 75 MPa for composites containing untreated glass fibres and 19 MPa and 52 MPa for pure PP and PA6. Addition of 5 wt% PP-g-MA compatibiliser to the PP composite increased the tensile strength by another 14%, i.e. to 56 MPa. The good interfacial compatibility achieved by APS surface treatment and compatibilisation was verified by Scanning Electron Microscopy (SEM).
Rheological Properties of High Molecular Weight Poly(vinyl alcohol)/Dimethyl Sulfoxide/Water Concentrated Solutions
Authors: Lee Sung Jun , Kwak Jin Woo , Kim Hyo Dae , Jeon Han Yong , Kim Joon Ho , Yoon Won Sik , Lyoo Won Seok
Published: September 2018

To establish basic data for the gel spinning of high molecular weigh (HMW) poly(vinyl alcohol) (PVA), the rheological properties of solutions of HMW PVA with a number-average degree of polymerization of 4,000 in dimethyl sulfoxide (DMSO)/water mixture were investigated in terms of three different polymer concentrations, 10 g/dl, 12 g/dl, and 14 g/dl, and various solution temperatures. Polymer concentration and solution temperature played a significant role in the rheological behaviour of HMW PVA solutions. Over the frequency range of 10-1 to 103 rad/s examined, PVA solutions showed shear thinning behaviour at lower temperatures. Furthermore, as the polymer concentration was increased, the extent of shear thinning also increased. In the plot of storage modulus of PVA solution with loss modulus, the slope was less than 2, indicating that the phase of PVA solutions in DMSO/water is heterogeneous.
Preparation of Cellulose Acetate/Nano-SiO2 Composites and their Application in Filtration of Cigarette Smoke
Authors: Cao Jianhua , Xiaolong Ma , Yang Aijun , Xu Wenju
Published: September 2018

Cellulose acetate/nano-SiO2 composites were prepared and spun into fibers. Their morphology and tensile properties were investigated by scanning electron microscopy, specific surface area analysis by BET and static mechanical analysis. The results showed that the composite fibers had an optimal filtration effect on the tar and nicotine in cigarette smoke. Compared with conventional cellulose acetate fibers, the composite ones had greater specific surface area, and the reduction in tar and nicotine in the smoke after filtration with the composite fibers was 44% and 35%.
A Study of the Electrospinning of an H2O–Acetone–PCL Ternary System
Authors: Xiaoqiang Li , Yan Su , Chuanglong He , Hongsheng Wang , Xiumei Mo
Published: September 2018

The aim of this study was to investigate the electrospinning of a ternary system consisting of water, acetone, and poly(e-caprolactone) (PCL) in order to prepare bead/block-type nano/microfibres as innovative cell-growth scaffolds with potentially controllable drug-releasing capabilities. Experimental cloud point data were obtained by cloud point titration. The phase diagram for the ternary H2O–acetone–PCL system was determined from the cloud point data. The ternary phase diagram can be used to investigate the mechanism of fibre formation, which is unlike that of traditional electrospun fibres. Bead-like nano/microfibres of the given ternary system were successfully fabricated by electrospinning.
Microencapsulation of Hydrophilic Solid Powder as a Fire Retardant by the Method of in situ Gelation in Droplets Using a Non-aqueous Solvent as the Continuous Phase
Authors: Takahashi Masanori , Taguchi Yoshinari , Tanaka Masato
Published: September 2018

Hydrophilic, solid, powdery diammonium bitetrazole (BHT.2NH3) as a fire retardant was microencapsulated with epoxy resin by the method of in situ gelation in droplets to give water resistance. In this method, a non-aqueous solvent was adopted as the continuous phase instead of water to prevent the hydrophilic core material from leaking out. In the experiment, it was mainly the agitation speeds during preparation of droplets containing BHT.2NH3 and during the microencapsulation process, the gelation temperature, and the oil-soluble surfactant species that were varied. The content of core material could be increased by using a non-aqueous solvent instead of water phase. The content of core material increased with gelation temperature and independently of the agitation speeds during first droplet preparation and during the microencapsulating process. The leakage ratio increased with agitation speeds and decreased considerably with gelation temperature.
Preparation of Natural Rubber/Cassava Starch/Organo-montmorillonite Biodegradable Nanocomposite Elastomers
Authors: Chuayjuljit Saowaroj , Wiriyasoonthorn Sirinun , Jiratumnukul Nantana , Limpanart Sarinthorn
Published: September 2018

Biodegradable nanocomposite elastomers were produced from natural rubber (NR) latex, cassava starch and montmorillonite (MMT). NR/cassava starch mixtures by dry weight ratios of 100/30, 100/40 and 100/50 were mixed with organomodified MMT (OMMT) at 4 parts per hundred of dry rubber. The obtained homogeneous latex mixture was cast into 2 mm thick sheets, dried under an infrared lamp for 6 h, in an oven at 70 °C for 6 h and then cured at 110 °C for 3 h. After curing, samples were examined for their structures, tensile properties, water absorption, biodegradability and morphology. The X-ray diffractograms and transmission electron micrographs showed that the nanocomposites formed were exfoliated. Their tensile strength decreased with increasing cassava starch composition. However, enhancement of the tensile strength was observed when OMMT was incorporated. The water absorption also increased in proportion to the starch content in the nanocomposites. After soil burial for four weeks, the percent weight loss and biodegradability of the nanocomposites were both enhanced markedly as the proportion of starch in the composite increased.
Research with Cfx Software on Frame Mould Temperature Field Simulation in Autoclave Process
Authors: Cheng Zhang , Yonggui Wang , Xianzhu Liang , Boming Zhang , Guangquan Yue , Peng Jiang
Published: September 2018

For autoclave technology in large complex structure manufacturing of composite materials, temperature distribution is the most important factor in process control. Previous researchers have mainly focused on composite exothermic curing reaction and exterior temperature coupling. For the exterior temperature field (especially mould temperature field), a simplified approach of uniformity was also conventionally adopted in those researches. Actually, moulds commonly utilised in autoclave processes have a frame structure and their temperature field variation is a combined heat transfer mechanism involving solid heat conduction, air heat conduction and forced convection. Hence in any phase of an autoclave process, the mould temperature field is non-uniform in the spatial domain. This non-uniform distribution of mould temperature has an important impact on the curing degree distribution and leads to residual stress. In this work, using ANSYS CFX computational fluid dynamics (CFD) software, simulation methodology for frame mould temperature field in autoclave process has been established, and its effectiveness has been verified experimentally. On this basis, a series of frame mould simulation examples has been developed and the impact of mould design parameters on the temperature field was achieved. The results will be of value in frame mould design and manufacturing defect control of composite structures.
The Effect of Compatibilising Agent and Surface Modification on the Physical Properties of Short Pineapple Leaf Fibre (Palf) Reinforced High Impact Polystyrene (Hips) Composites
Authors: Siregar J.P. , Sapuan S. M. , Rahman M.Z.A. , Zaman H.M.D.K.
Published: September 2018

The aim of this study was to investigate the effects of compatibilising agent and surface modification of short pineapple leaf fibre on physical properties of short pineapple leaf fibre reinforced high impact polystyrene (HIPS) composites. The purpose of using the compatibilising agents in this study was to modify the HIPS which include the polystyrene-block-poly(ethylene-ran-butylene)-block-poly(styrene-graft-maleic anhydride) and poly(styrene-co-maleic anhydride). Meanwhile, the alkali treatment was also used to modify the natural fibre surface of short PALF. The results have shown that adding compatibilising agent has improved the physical properties of the composites more effectively than by only using alkali treatment to modify the natural fibre surface.
Influence of Compatibiliser and Wood Flour on the Non-Isothermal Crystallisation Behaviour of Polypropylene Composites
Authors: Guo Chuigen , Ma Lichun , Wang Qingwen
Published: September 2018

The influence of m-isopropenyl-±,±dimethylbenzyl isocyanate grafted polypropylene (m-TMI-g-PP) and wood flour (WF) on the non-isothermal crystallisation behaviour of wood flour/polypropylene (WF/PP) composites was studied by differential scanning calorimetry. The crystalline morphology of PP was observed by polarised optical microscopy. The results demonstrated that the wood flour induces nucleation, while m-TMI-g-PP could greatly reduce the number of nucleation sites of the WF.

Avrami analysis showed that the non-isothermal crystallisation of PP and its composites followed the Avrami equation. The activation energy was calculated by using the Kissinger method, and the values were 253.3, 197.4 and 203.1kJ·mol-1 for PP, WF/PP and WF/m-TMI-g-PP/PP, respectively. This proved the nucleation effect of WF; the effect was much smaller in the presence of compatibiliser. The results indicate that the presence of m-TMI-g-PP generates a compatibilisation phenomenon, which leads to a reduction in the crystallisation rate, crystallisation temperature and crystallinity, and an increase in activation energy of PP compared with WF/PP composite.
Ionically Conducting Polymers Based on Ionic Liquid-Plasticized Starch Containing Lithium Chloride
Authors: Ning Wang , Xingxiang Zhang , Haihui Liu , Na Han
Published: September 2018

Ionic liquids (ILs) comprising 1-allyl-3-methylimidazolium chloride ([amim]Cl) with certain concentrations of lithium chloride (LiCl), have been used to prepare cast samples of ionically-conducting thermoplastic starch (TPS), with potential applications as solid biopolymer electrolytes. Atomic force microscopy (AFM) found that the diameter of residual starch granules existing in [amim]Cl and glycerol-plasticized starch films was about 10 nm. An increased concentration of LiCl tended to decrease the proportion of residual starch granules and form homogeneous TPS. LiCl also increased the interaction of [amim]Cl with plasticized starch, as detected by Fourier Transform infrared (FT-IR) spectroscopy and dynamic mechanical thermal analysis (DMTA). Thermogravimetric analysis (TGA) indicated that the supramolecular structure of starch was destroyed by [amim]Cl and LiCl. LiCl not only increased the water absorption of TPS, but also improved its electrical conductivity; the latter achieved values as high as 101.0 S cm-1 at 20 wt.% water absorption.
An Investigation of the Electromagnetic Shielding Effectiveness of Ethylene Vinyl Acetate Elastomer Reinforced with Carbon Nanofillers
Authors: Ray Moumita , George Jinu Jacob , Chakraborty Ajay , Bhowmick Anil K.
Published: September 2018

Electrically conducting polymeric composites are gaining popularity not only due to their light weight, corrosion resistance, flexibility and low cost, but also due to their electromagnetic interference (EMI) shielding ability. A novel ethylene vinyl acetate (EVA)-carbon nanofibre (CNF) nanocomposite has been successfully developed, and its electromagnetic interference shielding effectiveness (SE) was measured in the frequency range of 8–12 GHz. The dependence of SE on the applied electromagnetic frequency and the amount of filler loading has been evaluated. The SE of the composites was found to be directly proportional to the applied electromagnetic frequency and the amount of filler. Incorporation of 16 wt.% of CNF produced the optimum SE. The AC conductivity of the CNF reinforced EVA composites has also been measured in order to correlate the conductivity values with the SE of the respective composites. The level of filler loading governed the conductive network formation and hence the SE and conductivity. In order to do a comparative study of SE, three other carbon based nanofillers such as multiwalled carbon nanotube (MWCNT), expanded graphite (EG) and conductive carbon black (CB) have been used in this study. Morphological studies using transmission electron microscopy (TEM) supports various findings. These results indicate that CNF is an effective filler for the development of composites with excellent EMI shielding capability.
Nucleation Effect of Thermotropic Liquid Crystalline Polymer on the Crystallization of Poly(ε-Caprolactone)
Authors: Wu Defeng , Zhang Yisheng , Zhang Ming , Gao Minge
Published: September 2018

Poly(ε-caprolactone) (PCL) has attracted much attention in recent years due to its good biodegradability and biocompatibility. As a semicrystalline polymer, the final properties of PCL strongly depend on its bulk crystallization level. However, PCL shows a lower crystallization temperature and rate than other aliphatic polyesters, which restricts its range of applications. To improve the crystallization is hence a key problem to enhance the performance of PCL materials. In this work, a thermotropic liquid crystalline polymer (TLCP) was used as a nucleating agent to improve the crystallization of PCL. The PCL/TLCP blend with the maximum TLCP content of 10 wt.% was prepared by melt mixing. The nonisothermal crystallization behaviour of the PCL matrix was studied using differential scanning calorimetry (DSC) and polarized optical microscopy (POM), and the crystallization kinetics was then further analysed by methods including the Avrami, Ozawa, Mo, Ziabicki, Lauritzen-Hoffman and Kissinger models. The results showed that the presence of the solid TLCP particles could enhance crystallization temperature of the PCL matrix evidently at very small content levels (1 wt.%). Although the mobility of the PCL chain segments decreased with increasing TLCP content, heterogeneous nucleation by TLCP particles always played a dominant role in the overall crystallization. Therefore the blends showed higher crystallization rates and ability than those of pure PCL. The kinetic analysis and the data obtained in this work could be useful to optimize the processing conditions and to improve the crystallization of PCL.
Preparation and Characterization of Corncob-g-Acrylamide/Methacrylic Acid
Authors: Song Yan , Song Yiye , Zhang Mingming
Published: September 2018

Corncob was modified by graft copolymerization to widen its range of applications. Grafted corncob was prepared by graft copolymerization of acrylamide (AAm) and methacrylic acid (MAA) onto corncob using ferrous ammonium sulfate/H2O2 as a redox initiator. Grafted corncob was characterized by Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), respectively. The results showed that AAm and MAA were successfully grafted onto corncob's backbone, and the grafted corncob's thermal stability improved. The effects of monomer mass ratio, initiator concentration, reaction temperature and time on graft copolymerization had been studied in detail. Taking grafting percentage and grafting efficiency as functions, the optimum reaction conditions were obtained as follows: m (AAm): m (MAA) = 2:1; Monomer = 3 g; [FeAmSO4] = 1.0×10-2 mol/L; [H2O2] = 0.15 mol/L; T = 70 °C; Time = 2 h. The grafted corncob has a potential application in heavy metal ions wastewater treatment.
Synthesis, Characterisation and Properties of Polyurethane Grafted Chlorinated Polypropylene and its Composites
Authors: Wang Xuemin , Dong Xueru , Liu Dazhuang
Published: September 2018

The performance of chlorinated polypropylene (CPP) can be improved by grafting polyurethane (PU) onto it. PU grafted CPP (PU-g-CPP) has been synthesised via the inter-chain polymer reactions between maleated CPP (MCPP) and PU prepolymers containing free isocyanate (NCO) group in the presence of xylene as solvent and tertiary amine as catalyst. Various conditions for the reaction and the performance of the graft mixture (PU/MCPP composites) were optimised. The potential crosslinking and gelation were avoided successfully by dropping MCPP and controlling the mole ratio of PU prepolymers to MCPP. Different PU prepolymers and extenders had distinct effects on the solidifying characteristics and the adhesive capacity of PU/MCPP composites. The target graft products were characterised by FT-IR spectroscopy and differential scanning calorimetry (DSC) techniques.
Effect of Salicylic Acid on the Mechanical Properties and Water Resistance of Soy Protein Isolate Films
Authors: Bai Huiyu , Kumar Rakesh , Yang Cheng , Liu Xiaoya , Zhang Lina
Published: September 2018

Soy protein composites films (SF) have been prepared using soy protein isolate (SPI), salicylic acid (SA) and glycerol as a plasticizer. To prepare water resistant soy protein composites films (SF-B), 2, 2-diphenyl-2-hydroxyethanoic acid (DPHEAc) was used. Different amounts of SA were added in both SF and SF-B films. The results showed that the SF-B films with 0.5% (wt) of SA had higher tensile strength and modulus with low water uptake than that of SF films at same amount of SA. Contact angle analysis also indicated that the SF-B films showed hydrophobic surface. Thus both lower levels of water uptake and hydrophobic surface indicated high water resistance of the materials. Higher transmittance value and increased intermolecular hydrogen bonding showed higher compatibility between SPI and SA. This work provided a new approach in the use of SA in water resistant soy protein films for enhancing the processing window.
Thermal Properties of High Density Polyethylene-Kenaf Cellulose Composites
Authors: Tajeddin Behjat , Abdulah Luqman Chuah
Published: September 2018

Biocomposites of high density polyethylene (HDPE) and kenaf cellulose (KC) with polyethylene glycol (PEG) have been prepared by melt blending and compression moulding. The optimum temperature and reaction period for blending KC with HDPE were 145 °C and 12 minutes with rotation speed of 30 rpm, respectively. The effects of composition on the thermal properties of HDPE-KC biocomposites were investigated using TGA and DSC. Each sample of HDPE-KC biocomposites was subjected to heating programs between 35–600 °C for TGA, and the DSC analysis was determined under heating cycles of 25–600 °C. The results from TGA and DSC indicated that by increasing the KC content, the thermal stability was slightly improved. The melting temperature for all the composites was less than the melting point of KC (148.70 °C), and almost the same as that of HDPE (130.38 °C). Therefore no significant change in the melting temperature resulted from adding KC to the HDPE matrix. However, HDPE's presence surrounding the KC fibres, prevented water from reaching the cellulose fibre particles, thus reducing the water content in the composite; hence a significant advantage of forming KC composites with hydrophobic HDPE is that it helps to make the cellulose hydrophobic instead of hydrophilic.
Preparation of Heat-Resistant Epoxy/Silica Hybrids through a Novel Sol-Gel Process
Authors: Xia Xue , Wang Guoqing , Yang Peng , Kagawa Hiroyuki , Wang Haitao , Suzuki Masahiro , Zhong Wei , Du Qiangguo
Published: September 2018

A series of hybrid materials based on the diglycidyl ether of bisphenol-A (DGEBA) and 3-glycidoxypropyltrimethoxysilane(GPTMS) were prepared via a modified sol-gel process. The curing process of hybrid materials was analyzed with an advanced rheometric expansion system (ARES) and differential scanning calorimetry (DSC). Dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were carried out to evaluate the thermal properties of the resulted epoxy hybrids. Copper clad laminates were also prepared by a traditional hot-press moulding procedure with the hybrid varnish, which showed an excellent heat-resistant performance This kind of hybrid material may be suitable for electronic applications due to their excellent high temperature reliability and stability.
New Generation Amphoteric Comb-like Copolymer Superplasticizer and Its Properties
Authors: Miao Changwen , Ran Qianping , Liu Jiaping , Mao Yonglin , Shang Yan , Sha Jianfang
Published: September 2018

The incorporation of high performance superplasticizers in concrete is one of the most effective and economic technological methods for achieving sustainable development in the concrete industry. Conventional polyelectrolyte-type superplasticizers have some defects, e.g. poor dispersibility, large slump loss, increasing the shrinkage of concrete and pollution when being manufactured. Although the new generation of comb-like polycarboxylate superplasticizers has remarkable benefits in practice, it also has the shortcoming of low saturation dosage. In this study, based on adsorption-dispersion mechanism of dispersant and polyampholyte solution theory, a new class of amphoteric comb-like copolymer superplasticizer (PACP) was designed and synthesized. The effects of PACP on water reduction, setting, compressive strength, hydration and pore structure were investigated systematically. Results show that PACP can be dosed in small amounts to obtain a water reduction up to 45%. The addition of PACP also does not retard cement hydration and significantly increases the compressive strength of hardened concrete at early and ultimate stages. Moreover, PACP can further improve the rate of heat evolution, delays the time to reach the highest hydration temperature and refines the pore structure of hardened cement paste markedly, leading to decreases of porosity and average pore size.
Failure Load of Mechanically Fastened Immersed Composite Laminated Plates under a Preloaded Moment
Authors: Çiplak Emre , Sayman Onur
Published: September 2018

The effect of water absorption and corrosive sea water on the failure response of an angle ply glass fibre reinforced-epoxy composite oriented as [0/0/90/45]s has been experimentally investigated. The specimens were first tested in unimmersed conditions, and afterwards another group of specimens was immersed in sea water for 200 days. The experiments were performed using some parameters for the pinned and bolted specimens. The specimens were tested under pre-load moments of 3 Nm and 6 Nm. The results point out that the pre-load moments increase the failure load. Moreover, immersion of the composite specimens into the sea water under preload moments can cause a notable decrease of the failure load.
Experimental Investigation of the Longitudinal Compressive Strength of Carbon Fibres with a Direct Measurement System
Authors: Boming Zhang , Yufen Wu , Zhong Yang , Xiaohong Wang
Published: September 2018

Characterization of the mechanical properties of carbon fibres is crucial to the design of fibre reinforced composite materials. However, little has been done due to the complexity and inaccuracy of some of the necessary tests. In order to study the compressive properties of single fibres, a direct system for single carbon fibre compressive strength was set up based on previous studies; several kind of PAN-based carbon fibres were examined at specimen gauge lengths from 20 to 150 μm using this system. It was discovered that the experimental compressive strength was constant when the length of carbon was in the range of 20~90 um; when the sample's length was beyond 90 μm, the compressive strength decreased sharply. The reason is that its deformation mode was not compressive but buckling. In order to compare with corresponding tensile behaviour, a tensile strength test was also carried out, and it was discovered that the compressive strength was about 50% of the tensile strength for single fibres.
Dough-Moulding Compound Reinforced Methyl Vinyl Silicone Rubber with Silica Filler
Authors: Wu Wei-li
Published: September 2018

Methyl vinyl silicon rubber (MVQ) composites were reinforced by adough-moulding compound (DMC), in which silica was used as filler by blending method. The influences of silica and DMC content, and cure conditions on the mechanical and thermal properties of the composites were investigated. The compatibility and crosslinking structure of the composites were examined by SEM and Fourier transform infrared spectroscopy (FTIR) analysis. The results showed that DMC/MVQ composites had very good mechanical and thermal properties when the formula of the compound was MVQ 100, DMC 70 and silica 35 phr, and the cure conditions were 170 °C for 30 min under 10 MPa. The compatibility between DMC and MVQ was good, and C-O-C bonds between unsaturated polyester (UP) and MVQ were revealed by FTIR analysis. The mechanical and thermal properties of DMC/MVQ were obviously improved.
Disperse Dyeability of Polypropylene Fibres via Microwave and Ultrasonic Energy
Authors: Yiğit Elif Atabek , Teker Murat
Published: September 2018

In this study, the dyeability of polypropylene fibres with a disperse dye via microwave and ultrasonic energy was examined. A dye bath having a liquor-to-goods ratio of 20:1, and including dyestuff 2% owf was prepared and dyeing experiments using microwave and ultrasonic energy were carried out. In the case of microwave dyeing, experiments have been carried out at different energy levels (L, M-L, M, M-H and H) and different time ranges (1 to 5 min) while in the case of ultrasonic energy different temperatures (20, 40, 60 and 80 °C) and different time range (1 min to 30 min) were used. Additionally, effect of carrier was also investigated. Dyed samples were examined by determining their K/S values. Diffusion coefficients in all methods were calculated using Shibusawa's approximation of Hill's equation. Washing fastnesses of dyed samples were also examined. This study showed that the dyeability of polypropylene fibres was increased by both microwave and ultrasonic energy.
Dependence of Amino-functionalization on Interfacial Adhesion Strength in Epoxy/Al Laminated Composites
Authors: Guo Qiwen , Peng Qingyu , Li Yibin , Mei Lei
Published: September 2018

In epoxy/Al laminated composites, the interface between polymers and metals plays the role of load transfer from epoxy to Al. However, the interfacial bonding between epoxy and aluminum tends to be weak. In this paper, in order to improve the interfacial strength the dendrimer layer—poly (amido amine) (PAMAM) was used to realize the amino functionalization of the interface of epoxy/Al laminated composites. The amino functionalization was tuned by controlling the hydroxyl group concentration through different Al surface treatments. The results show the interfacial adhesion strength between aluminum and epoxy was highly dependent of amino group content. The adhesion strength of epoxy/Al interface is increased by 50% after PAMAM layer was introduced into the NaOH-treated interface between epoxy and Al surface.
Fracture Behaviour of Adhesives Modified with various Rubber Content under Combined Stress Conditions
Authors: Imanaka Makoto , Sogawa Takuya
Published: September 2018

Rubber-modified adhesives have attracted special interest recently due to their property of dramatically increase in fracture toughness of adhesively bonded joints, where the fracture toughness increases with the rubber content. However, an increase in rubber content decreases the joint strength without initial flaws. Besides, most adhesively-bonded joints have combined normal and shear stresses concentrated in the adhesive layer. Hence, the effect of rubber content on adhesively-bonded joints should be clarified under combined stress conditions. In this paper the aim is to characterize the rubber content dependent behaviour of the rubber-modified adhesive under combined stress conditions. Tensile tests were conducted for adhesively-bonded butt and scarf joints with various rubber contents, where these joints can cover the combined stress conditions in the adhesive layers of most joints in industrial applications. The influence of the rubber content on the joint strength is represented in the normal stress-shear stress diagram.
The Low Velocity Impact Response of Nano Modified Composites Manufactured Using Automated Dry Fibre Placement
Authors: Umer R. , Rao S. , Zhou J. , Guan Z. , Cantwell W.J.
Published: September 2018

The low velocity impact response of composite materials manufactured from dry fibre tows using the automated fibre placement technique has been investigated. Following fibre placement, the dry preforms were infused with an epoxy resin. The influence of incorporating graphene oxide (GO) nanoparticles into the matrix was investigated, and the impact response of these samples was compared to that of its plain resin counterpart. Flexural and low velocity impact tests were undertaken in this study to understand the influence of GO nano-filler loading on mechanical behaviour of the unreinforced epoxy resin. The introduction of GO into the resin showed nearly 50% increase in ductility compared with that of the neat polymer at a mere 0.1 wt% filler loading. However, GO had a negligible effect on the impact response of these novel composites. There was no observable difference between the load-displacement traces or the resulting damage in the plain and unmodified composites. It is possible that the polymer's ability to undergo larger non-linear deformation at lower rates of strain is suppressed when it is subjected to impact rates of loading.
Electrical Conductivity Studies of Conducting Polymer Nanocomposites in Ambient Conditions
Authors: Ansari Shahid Pervez , Mohammad Faiz
Published: September 2018

Nanocomposites of conducting polymer (polyaniline, PANI) nanoparticles with zinc oxide (ZnO) nanoparticles as inorganic filler and cellulose acetate (CA) as supporting matrix were prepared by a solution-casting method using N-methyl-2-pyrrolidone (NMP) as solvent. The nanocomposites were studied for their DC electrical conductivity and stability in terms of electrical conductivity retention by isothermal accelerated ageing and cyclic accelerated ageing techniques using a four-in-line probe instrument. The nanocomposites were also characterized by FTIR, SEM, TEM, TGA and XRD. All the nanocomposite formulations followed an Arrhenius-type temperature dependence of electrical conductivity, which supported a semiconducting nature for their HCl doped state. The electrical conductivity of the as-prepared HCl doped nanocomposites was also found to be in the semiconducting region. The studied nanocomposite formulations showed good stability towards retention of their electrical conductivity up to 90°C. X-ray diffractometry (XRD) data suggested the uniform incorporation of zinc oxide nanoparticles in the polymer matrix.
Studies on the Morphology, Cure Characteristics and Mechanical Properties of Acrylonitrile Butadiene Rubber with Hybrid Filler (Carbon Black / Silica) Composite
Authors: Senthilvel K. , Vishvanathperumal S. , Prabu B. , John Baruch L.
Published: September 2018

Carbon black (CB) and silica are the common reinforcing fillers that increase the usefulness of rubbers. In this work the effect of CB/silica hybrid fillers on the physico-mechanical properties of nitrile rubber was investigated. The total hybrid filler is kept constant at 50 phr (parts per hundred rubber) and silica content in the hybrid filler is varied as 0, 10, 20, 25, 30, 40 and 50 phr. Totally seven different combination of composite samples are prepared using two roll mill. Cure characteristics and physico-mechanical properties such as tensile strength, compressive strength, tear strength, elongation at break, 100%, 200% and 300% tensile modulus, abrasion resistance, hardness, compression set and rebound resilience are studied experimentally. Results showed that cure time t90, Scorch time ts2, minimumtorque (ML), and maximum torque (MH) of CB/Sil hybrid increased as silica content increased. The crosslink density of rubber hybrid composites has been determined from this stress strain curve using analytical method and ANSYS software. From the experimental results, it is found that all the properties studied except elongation at break, compression set, rebound resilience and abrasion resistance decreases with increase in silica content in hybrid filler as the silica content makes the composites less stiff.
Effect of Pretreatment Methods on Properties of Natural Fiber Composites: A Review
Authors: Venkatachalam N. , Navaneethakrishnan P. , Rajsekar R. , Shankar S.
Published: September 2018

India as a tropical agricultural country has great potential to develop and use fiber derived from agricultural waste. Natural fibers are an important by-product of extraction process and they can be used as reinforcement in composite products. Composites are developed with unsaturated polyester resin as the matrix with natural fiber as the reinforcement. The results show decreased strength and modulus with increasing the fiber volume fraction. This indicates ineffective stress transfer between the fiber and matrix due to lower adhesion. It is necessary to bring a hydrophobic nature to the fibers by suitable chemical treatments in order to develop composites with improved mechanical properties. In these review papers, different types of natural fibers are subjected to a variety of physical and chemical treatments. The types of treatments studied in these papers include Physical treatments such as beating and heating, and chemical treatments like alkalization, silane, acetylation and benzoylation. The effects of these treatments on mechanical properties of the composites are analyzed. Fractures are analyzed by using the scanning electron microscopy (SEM). Analysis by FTIR and DMA showed that physico-chemical changes of surfaces of treated natural fibers. In general, treatments to the fibers can significantly improve adhesion and reduce water absorption, thereby improving mechanical properties of the composites. The purpose of this review paper is to summarize the research work done on various pretreatments in the preparation of natural fiber reinforced composites and to highlight the potential use of natural fiber reinforced polymer composites in industry and its potential to replace the synthetic fiber composite and conventional materials in the future.
Investigation of Thermal and Ablative Properties of Modified Epoxy Resins
Authors: Bakar M. , Kucharczyk W. , Stawarz S.
Published: September 2018

The present work investigates the ablative and thermal properties of epoxy resins modified with silicon carbide (SiC) and tungsten carbide (WC). The properties of two epoxy resins (Epidian 52 cured with triethylenetetraamine and Epidian 112 cured with polyaminoamide) were investigated in this study. Statistical methods for planning experiments were used, and the effect of components on thermal protective properties of epoxy composites established. It was shown that the best thermal protective properties, i.e. the lowest temperature of the rear surface area and the lowest ablative weight loss (the highest thermal stability) were exhibited by the composite based on Epidian 112 containing 56% of silicon carbide SiC and 14% of tungsten carbide WC. A more stabilized ablative layer and limited erosion were obtained with higher SiC content. Moreover, the type of polymer matrix had the most significant effect on the value of the maximum temperature of the rear surface area.
Synthesis of Carbazole Based Co-polymers Containing Thienothiophene and Benzothiadiazole Units in a Direct Arylation Scheme
Authors: Sarjadi Mohd Sani , Iraqi Ahmed
Published: September 2018

The photovoltaic effect can be used to harvest energy from sunlight, enabling a cleaner approach to generating energy. Organic photovoltaics based on polymers are an attractive replacement of expensive, high energy consuming silicon solar cells. However, the limitations of efficiency have prevented industrial application, and polymer-based solar cells remain uncompetitive. Thus, optimisation of efficiency is required before potential application of these devices. In this work, the polymers were synthesised by direct arylation, in order to investigate its suitability for application in photovoltaic cell. Morphological, spectroscopic and charge-transport measurements are used to investigate the influence of either the dithienyl or thienothiophene moieties on the structure and photophysical properties of the copolymer rationalise the solar cell characteristics. The polymers obtained were characterised using 1H-NMR, 13C-NMR, IR, UV and thermal gravimetric analysis. The absorption spectral, thermal, electrochemical and photovoltaic properties of the random copolymers were investigated. Finally, a new series of carbazole-based dithienyl or thienothiophene polymers was successfully synthesised and characterised.