bluuebunny/crossref_metadata_2025 huggingface dataset:
Purification of Carbon Nanotubes and its Effect on the Properties of Carbon Nanotube/Polyaniline Nanocomposites
Authors: Zhao Dongyu , Su Kai , Gao Xuemei , Liu Xiangdong , Meng Yunfei , Yuan Weishu
Published: September 2018

Multi-wall carbon nanotubes were purified by the mixed acid (HNO3 and H2SO4). The multi-wall carbon nanotubes/polyaniline composite (MWCNTs/PANI) was prepared by in situ polymerisation using aniline monomer and nanotubes in HCl solution. The content of MWCNTs in the samples was 0Q20 wt.%. The results showed that the MWCNTs were well dispersed in water after purification. The interaction between PANI and MWCNTs was proved by FT-IR spectrometry. The conductivity and the tensile strength of the MWCNTs/PANI were improved obviously after purification.
Influence of Nanoclay on the Morphology, Adhesive and Mechanical Properties of Polysulfide Modified Epoxy Resin
Authors: Guchhait Prasanta K. , Pradhan Sudip , Kumar K. Dinesh , Maji Pradip K. , Bhowmick Anil K.
Published: September 2018

Addition of nanoclay particles to a typical tertiary amine cured polysulfide modified epoxy adhesive leads to large increase in the single-lap shear strength of aluminum-aluminum joint. The nanoclay particles are very well dispersed (near fully exfoliated) in the polymer matrix even at 8 wt.% of nanoclay concentration. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies provide evidences for the excellent dispersion of the nanoclay platelets in the polymer matrix. The addition of nanoclay particle results in a significant increase in the elongation at break values along with the marginal increase in the tensile strength. The nanoclay provides good ductility to the epoxy-polysulfide adhesive by forming very flexible interface, which leads to less brittle composite having good strength. The increase in work to break (Wb) values by the addition of nanoclay represents the potential for dissipating a greater amount of energy during the bond rupture process of the lap shear test, and hence the adhesive strength increases. In addition, the increase in joint strength by the addition of nanoclay can also be attributed to the good interaction between the epoxy-polysulfide adhesive and the aluminum substrate in the presence of nanoclay.
Effect of Barium Sulfate Nanoparticles on Mechanical Properties and Crystallization Behaviour of HDPE
Authors: Chen Xiaolei , Wang Luming , Shi Jiangao , Shi Hang , Liu Yongli
Published: September 2018

High density polyethylene (HDPE)-based composites were prepared by blending HDPE with BaSO4 nanoparticles, which had been treated with sodium stearate. Variations in crystallization behaviour, mechanical properties, storage modulus and damping parameter (tan d) with the addition of BaSO4 nanoparticles were investigated by SEM, XRD, DSC, DMA, etc. The crystallization rate steadily increased with the content of BaSO4 nanoparticles because of these nanoparticles acting as a heterogeneous nucleation agent. The impact strength of HDPE first increased and then decreased with increasing the content of BaSO4 nanoparticles. The maximum impact strength of HDPE nanocomposites was achieved at a weight ratio of BaSO4/HDPE = 1/100. However, the tensile yield stress gradually increased with the content of BaSO4 nanoparticles. Dynamic mechanical analysis data showed an increase in the storage modulus of composites with increasing content of BaSO4 nanoparticles. The tan d value of nanocomposites decreased in comparison to the neat HDPE. It was demonstrated that the BaSO4 nanoparticles treated with sodium stearate had stronger effective interface interaction with HDPE matrix and adding 1.0 wt.% modified BaSO4 nanoparticles could effectively reinforce HDPE matrix.
Preparation and Characterisation of Polyethylene/Clay Nanocomposites as a Flame Retardant Materials Using Ultrasonic Technique
Authors: Nour Mohamed , Eid Ahmed , El-Nagare Khaled , Aziz Fadia Abdel
Published: September 2018

Three polyethylene/clay formulations (3%, 7% and 10%) were prepared by ultrasonic technique of polyethylene (PE) and montmorillonite organically modified with imidazolium salt (OMC) in toluene as solvent. The prepared PE/OMC nanocomposites were characterised by colour measurement and atomic force microscopy (AFM). An intercalated, mixed intercalated–exfoliated and delaminated structure in PE/OMC nanocomposites with different OMC content were found. The thermal stability and flammability of PE/clay nanocomposites were measured by thermogravimetric analysis (TGA) and cone calorimetry. By adding 3, 7 and 10 phr organoclay, the peak heat release rate of the nanocomposite was reduced by 34.5, 45.4 and 50.5% respectively. Further studies indicated that the improvement of flammability performance was due to the formation of a clay enriched protective char during combustion.
Pressure Transfer Behaviour of Rubber Mould and the Effects on Consolidation of L-Shape Composite Laminates
Authors: Gu Yizhuo , Li Min , Li Yanxia , Zhang Zuoguang
Published: September 2018

A rubber mould is a crucial component for manufacturing resin matrix composite parts with complex structure, especially for autoclave process. This paper presents the experimental investigations on pressure transfer behaviour of a rubber mould. In order to measure the pressure distribution on the mould surface during processing to characterize the pressure transfer properties of rubber mould, a novel method was established using a kind of pressure sensitive paper. By means of this technique, it was found that obvious uneven pressure distribution appears on the interface between an L-shape rubber male mould and an aluminium die in autoclave process, including corner and flat sections. Moreover, the rubber modulus significantly affects the pressure distribution. Based on these results, the effects of rubber mould on the consolidation of L-shape composite laminates were studied, and there is a close relationship between the consolidation of composite laminates and the pressure transfer property of rubber mould. These results are valuable for studying defect formation and controlling the processing of complex composite structures in rubber mould assisted autoclave processes.
EPDM/HDPE-Based Thermoplastic Vulcanisates Studied by Physical-Mechanical Tests and IR Spectrometry
Authors: Moldovan Z. , Ionescu F. , Alexandrescu L. , Carsote C.
Published: September 2018

For the present study, blends of ethylene-propylene-diene terpolymer (EPDM) rubber with a thermoplastic polyolefin namely high-density polyethylene (HDPE) were prepared by dynamic vulcanisation. The physico-mechanical tests, IR spectra (recorded by attenuated total reflection technique) and aging behaviour of the binary blends were investigated, analyzing the effect of the rubber/thermoplastics ratio, the kind of reticulating agent and the percent of plasticizer on the properties of the prepared polymer blends.
Hybridization Effect of Glass Fibre on Mechanical, Morphological and Thermal Properties of Polypropylene-Bamboo/Glass Fibre Hybrid Composites
Authors: Nayak Sanjay K. , Mohanty Smita , Samal Sushanta K.
Published: September 2018

Polypropylene/bamboo fibre-reinforced composites (BFRP) and polypropylene-bamboo/glass fibre based hybrid composites (BGRP) using an intermeshing counter-rotating twin-screw extruder followed by injection moulding in which maleic anhydride grafted polypropylene (MAPP) was used as a compatibilizer. The effect of hybridization on the mechanical performance of hybrid composites has been assessed. It was observed that replacement of 15 wt.% of bamboo fibre by 15 wt.% of glass fibre with 2 wt.% of MAPP on a total amount of 30 wt.% of fibre content showed optimum mechanical performance. The water uptake of the hybrid composites was also found to be less than that of their unhybridized counterpart. The crystallization, melting behaviour and thermal stability of the hybrid composites were investigated employing differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA ). TGA thermograms showed an increase in thermal stability of the matrix polymer after incorporation of bamboo and glass fibres, confirming the effect of hybridization and efficient fibre matrix interfacial adhesion. The fibre-matrix interfacial morphology of the tensile fractured specimens was studied using scanning electron microscopy (SEM) which showed less fibre pullout and fewer gaps between the fibre and the base matrix in case of MAPP-treated hybrid composites.
Reactive Compatibilization and Elastomer Toughening of Poly(2,6-dimethyl-1,4-phenylene oxide)/Polyamide 6 Blends
Authors: Li Bo , Wan Chaoying , Zhang Yong , Ji Jiliang , Su Yu
Published: September 2018

Poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide 6 (PPO/PA6) blends were reactively compatibilized by maleic anhydride (MA) grafted PPO (PPO- g-MA) and toughened by MA grafted styrene-ethylene-butadiene-styrene block copolymer (SEBS) (SEBS- g-MA) via melt extrusion. The compatibilizing effect of PPO- g-MA on the PPO/PA6 blends was studied by using scanning electronic microscopy, differential scanning calorimetry and mechanical properties tests. The notched impact strength of PPO- g-MA/PPO/PA6/SEBS- g-MA blends increased with increasing SEBS- g-MA content, leading to blends having super-tough behaviour. The fracture behaviour of the PPO/PA6 blends was studied using a modified essential work of fracture model (EWF), which showed that plastic deformation related to SEBS- g-MA was the crucial factor for the toughening.
Effect of Poly(2-ethyl-2-oxazoline) on Multi-Walled Carbon Nanotubes Reinforced Poly(vinyl alcohol) Composites
Authors: Tan Soon Huat , Suk Kyoung Lim , Goak Jeung Choon , Hong Sung Chul , Kim Jeong-Yeol , Lee Sang-Won , Kim Sunjae , Seo Yongho , Lee Naesung
Published: September 2018

The effect of poly(2-ethyl-2-oxazoline) (PEOX) as a surface modifier for multi-walled carbon nanotubes (MWCNTs) in a poly(vinyl alcohol) (PVA) composite was studied through a simple polymer wrapping and melt extrusion processes. MWCNTs were carboxylated in a reaction with HNO3, followed by mixing with 10 wt.% PEOX in ethanol to produce a MWCNT-PEOX complex. High resolution transmission electron microscopy identified a PEOX layer existing on the surface of MWCNTs. Compared with pristine MWCNTs, MWCNT-PEOX showed an improved dispersion in hydrophilic solvents such as water and ethanol. The PVA composite reinforced with 0.5 wt.% MWCNT-PEOX exhibited ~54% higher Young's modulus than pure PVA.
Prediction of Process-induced Geometrical Deformations for Stiffened Thermosetting Composite Panels
Authors: Boming Zhang , Guangquan Yue
Published: September 2018

Stiffened thermosetting composite panels are primary structure of aircraft and fabricated with co-curing processing. The process-induced residual stresses resulted in geometrical deformation when the stiffened composite panel was fully cured and removed from the tool. An investigation into the three-dimensional cure simulation of T-shape stiffened thermosetting composite panels was presented to predict the process-induced deformation during co-curing. And flexible tools and locating tools were considered in the cure simulation. Simulation examples were presented to demonstrate use of the present finite element procedure for predicting composite parts deformations. The T300/BMI structure was analyzed provide insight into the non-uniform curing process. The temperature was higher in the interface between web and flange during the entire cure cycle. And the distortions of skin and webs for T-shape stiffened thermosetting composite panel were remarkable.
Thermal Oxidation Behaviour and Degradation Kinetics of Polypropylene with p-tert-Butylcalix[n]arenes
Authors: Zhu Linhua , Xu Kai , Chen Jia , Chen Mingcai
Published: September 2018

p-tert-butylcalix[4]arene (C4), p-tert-butylcalix [6]arene (C6) and p-tert-butylcalix[8]arene (C8) were synthesized and explored as antioxidants for polypropylene (PP). The structures of these compounds were characterized by 1H-NMR and FTIR, and their antioxidation efficiencies for PP were evaluated by rheology analysis, differential scanning calorimetry (DSC), melt flow index analysis, and thermogravimetric analysis (TGA). The rheology results from a Haake Polydrive mixer revealed that calix[n]arenes had little effect in preventing PP from degradation during the processing, and the DSC analysis showed that the antioxidation performance of the calix[n]arenes for PP was in the order of C4 > C6> C8. The values of melt flow index indicated that calix[n]arenes, especially C4 and C6, could largely improve the thermal stability of PP, and the activation energies for degradation of PP with C4, C6 and C8 calculated with the data from TGA were 97.05, 84.60 and 53.69 kJ/mol, respectively.
The Study of Epoxy Methacrylate/Silica Hybrid
Authors: Ou Cheng-Fang , Shiu Ming-Chin
Published: September 2018

A series of epoxy methacrylate/silica hybrids, containing 0.5, 1, 3, 5, 7, 10, and 15 wt.% tetraethyloxysilane (TEOS), were synthesized by sol-gel process. Differential scanning calorimetry (DSC) indicated that the glass transition temperatures (Tg) of the hybrids were higher than that of the pure epoxy methacrylate, the maximum increase of 26.7 °C being achieved with the addition of 3 wt.% TEOS. The decomposition temperatures (Td) of the hybrids were higher than that of the pure epoxy methacrylate (EMA) and rose as the TEOS content increased. The light transmittance of the hybrids was still higher than 80% with up to 15 wt.% TEOS. The water permeability of the hybrids decreased with increasing TEOS content to 7 wt.%, and then increased to 15 wt.%. The hybrid with 7 wt.% TEOS exhibited a maximum permeability decrease of 54.0%. Scanning electron microscopy (SEM) showed that the number of dispersed droplet of silica increased as the content of TEOS increased.
Solar and Environmental Degradation Effect on Tensile Strength and Glass Transition Temperature of Glass Fibre Reinforced Plastic Laminates
Authors: Sevim Cenk , Varlikli Canan
Published: September 2018

In this study, solar and environmental degradation were performed for glass fibre/epoxy and glass fibre/vinyl ester composites. Tensile and differential scanning calorimetry (DSC) tests were applied before and after degradations. Considering tensile strength, it is concluded that vinyl ester composite samples used in this study were more durable against environmental degradation compared to the epoxy based samples. On the contrary, epoxy based samples seemed to be more durable than those of the vinyl ester under solar degradation. Moreover, the glass transition temperature loss % of both two resins was very low after solar degradation. It was observed that the destructive effect of environmental degradation was more dominant than solar degradation, according to measurements of tensile strength and glass transition temperature values.
Properties of Thermoplastic Polyurethane/Functionalised Graphene Sheet Nanocomposites Prepared by the in Situ Polymerisation Method
Authors: Nguyen Duc Anh , Raghu Anjanapura V. , Choi Jin Taek , Jeong Han Mo
Published: September 2018

Thermoplastic polyurethane (TPU)/functionalised graphene sheet (FGS) nanocomposites were prepared by an in situ polymerisation method. The synthesised TPU/FGS nanocomposites were fully characterised by FT-IR, TEM, TGA, DSC, DMA, and by measurements of electrical conductivity and mechanical properties. The results indicated that the chemical and/or physical interactions between FGS and TPU were enhanced in the nanocomposites prepared by the in situ polymerisation method, and were compared to those of an earlier study which were prepared by physical mixing. Thermogravimetry showed that the degree of TPU adherence onto the FGS increased when the nanocomposite was prepared by the in situ polymerisation method. There were pronounced modulus enhancements and decreases in tensile strength and elongation at break as a result of incorporating FGS. The FGS, well dispersed in the TPU matrix, effectively improved the electrical conductivity; the nanocomposite containing 2 parts FGS per 100 parts TPU had an electrical conductivity of 2.07×103 S/cm, about 108 times higher than that of the pristine TPU.
Preparation of Sodium Alginate Hydrogel Microparticles by Electrospinning Using Various Types of Salts
Authors: Kim Sun Gil , Lee Young Jae , Shin Eun Joo , Gal Yeong Soon , Lee Yong Rok , Oh Tae Hwan , Choi Han Gon , Kim Jung-Ae , Yong Chul Soon , Han Sung Soo , Noh Seok Kyun , Lyoo Won Seok
Published: September 2018

Sodium alginate (SA) hydrogel microparticles were simply obtained by using electrospinning method at diverse processing parameters such as polymer concentration, applied voltage, tip to collector distance (TCD), and type and amount of divalent cations (crosslinking and gelation agents). In the case of TCD, there is no significant on the morphological shape of SA hydrogel microparticle. On the contrary, the particle size was decreased with an increase in the applied voltage. But at a high applied voltage, the polydispersity of SA hydrogel microparticle was increased and broad range of particle sizes was observed. Nearly monodisperse microparticles were prepared at applied voltage of 10kV. We also obtained SA hydrogel microparticles by the exchange of sodium ions with divalent cations such as Sr2+ and Ba2+, which presented uniform spherical shape, in comparison with that prepared using Ca2+.
Influence of Different Curing Systems on the Physico-Mechanical and Rheological Properties of CSM Rubber
Authors: Nanda Madhuri , Tripathy Deba Kumar
Published: September 2018

Curing systems play a vital role in designing rubber compounds for various industrial applications. Keeping this in view, a comparative study of the effects of four different curing systems such as sulfur, dicumyl peroxide (DCP), metal oxide (PbO) and epoxy resin on the curing characteristics, physico-mechanical, and rheological properties of chlorosulfonated polyethylene rubber (CSM) has been carried out. The highest values of maximum rheometric torque and scorch safety were observed in the peroxide-cured system, whereas sulfur-cured CSM rubber compounds possessed superior mechanical and rheological properties compared to those of the other cured systems. It is interesting to note that all curing systems exhibited increases in tensile strength, hardness, tear strength and crosslink density after aging. This may be due to post vulcanization. Unlike uncured CSM compound, in cured CSM compound the loss tangent increased with frequency, which may be due to the insufficient time available for molecular relaxation. Probable crosslinked structures for different curing systems have been proposed based on the observations of attenuated total reflectance Fourier transform infrared spectroscopy.
Investigation on Flame Retardancy and Antidripping of New Intumescent Flame Retardant Polypropylene Film
Authors: Bai Peng , Li Bin , Gao Suliang , Lin Mo , Wang Mi
Published: September 2018

A novel intumescent flame retardant (IFR) system consisting of a novel char forming agent (CFA), modified ammonium polyphosphate (MAPP), a synergistic agent (4A zeolite) and an antidripping agent (SN3300) was used in an intumescent flame retardant polypropylene film (IFR-PP film). The original ammonium polyphosphate (OAPP) was modified by octadecylamine to enhance its compatibility with the PP matrix. According to the results obtained from the flame retardancy tests, MAPP had a higher efficiency than OAPP, and the IFR-PP film without the antidripping agent reached a high limiting oxygen index (LOI) value, but it failed to pass UL-94 VTM-0 rating (0.2 mm). The reasonable loading of SN3300 was 0.10~0.15 wt.% (26 wt.% loading of IFR). Greater or smaller loadings did not help the samples to pass VTM-0 rating, and even deteriorated the flame-retardancy of the film. Based on thermogravimetric analytical data, the IFR enhanced the thermal stability of composites at high temperature and effectively increased the char residue. The cone results demonstrated that the IFR could reduce the flammability of PP films based on reduced heat release rate (HRR), total heat release (THR), smoke production rate (SPR) and total smoke production (TSP); also IFR containing MAPP became more effective in reducing smoke release than one containing OAPP The mechanical properties test results showed that films containing MAPP had better tensile strength and tear strength. The morphological structures observed by scanning electron microscopy (SEM) showed that MAPP had much better compatibility with a PP matrix than OAPP, and it made the char layer become more homogeneous and dense.
Structures and Mechanical Properties of Polyurethane/Clay Composites Prepared by Different Pre-mixing Procedures
Authors: Yeh Jen-Taut , Suen Maw-Cherng , Lai Yu-Ching , Lee Hsun-Tsing , Chen Cheng-Chi
Published: September 2018

A novel method for preparing polyurethane/nano-clay composites was used in this study. The nano-clay was pre-mixed with the various components, such as diphenylmethane diisocyanate (MDI), 2,2-bis(hydroxymethyl) propionic acid (DMPA) or polytetramethyleneglycol (PTMG), of polyurethane (PU) polymer to prepare the composites. The PU/clay composites prepared by this method revealed that the values of the tensile strength at break, the elongation at break, the modulus and the surface roughness for the composite prepared from the pre-mixture of clay and PTMG (PU/clay-PTMG composite) were higher than those for the composite prepared from the pre-mixture of clay and MDI (PU/clay-MDI composite), the composite prepared from the pre-mixture of clay and DMPA (PU/clay-DMPA composite) and PU. The thickness of the crystals for PU/clay-MDI and PU/clay-DMPA composites was larger than that for PU and PU/clay-PTMG; whereas the layer distance of the crystals for PU/clay-MDI and PU/clay-DMPA composites was smaller than those for PU and PU/clay-PTMG. The values of glass transition temperature (Tg) of soft and hard segments were in the order of PU/clay-MDI > PU/clay-DMPA > PU > PU/clay-PTMG. Among the three PU/clay composites prepared by the pre-mixing procedure, PU/clay-MDI and PU/clay-DMPA composites showed significant gathering of the nano-clay in the PU matrix. A possible mechanism of the structural changes under tensile stress was speculated to explain the reason for the higher tensile strength and elongation at break of PU/clay-PTMG composite. The pre-mixing of clay-PTMG was a good procedure for the manufacture of the PU/clay composite, which had higher values of tensile strength and elongation at break.
Effects of MWNTs-COOH on the Combustion Behaviour and the Flame Retardancy Properties of PET
Authors: Zhang Jianjun , Zhang Jingzong , Ji Quan , Tan Liwen , Xia Yanzhi , Kong Qingshan
Published: September 2018

Novel carboxyl-modified MWNTs-containing PET nanocomposites (PET/MWNTs-COOH) were successfully prepared via an in-situ method. Thermal stability and flame-retardancy properties of PET/MWNTs-COOH nanocomposites were investigated by cone calorimetry (CONE), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The CONE calorimetry results showed that PET/MWNTs-COOH had a lower heat release rate (HRR) and total smoke production (TSR), compared with those of pure PET. TGA indicated that the incorporation of MWNTs-COOH increased the char residues and improved the thermal stability of pure PET SEM images of the char crusts showed that PET/MWNTs-COOH formed more continuous and thicker char residues than those formed with pure PET during combustion. The above results indicated that combustion behaviour and flame retardancy properties of the MWNTs-COOH/PET nanocomposites were sufficiently enhanced that MWNTs-COOH could act as a flame retardancy agent for a PET matrix. Condensed phase and gas phase mechanisms were proposed for the PET/MWNTs-COOH flame-retardancy effect.
Synthesis and Characterization of Polyimide/Silica Nanocomposites with Coupling Agent
Authors: Chou Shang-Chih , Cheng Yao-Yi , Dai Chi-An
Published: September 2018

In this study, silica particles were introduced into a polyimide (PI) matrix to enhance its thermal and mechanical properties. Monomers of 3,3’,4,4'-biphenyl tetracarboxylic dianhydride (BPDA) and p-phenylenediamine (p-PDA) were employed to synthesize the poly(amic acid) (PAA). Polyimide/SiO2 composites were obtained through a sol-gel process using tetraethoxysilane and multi-step thermal curing processes. The properties of the PI/SiO2 composites with various kinds of coupling agents to enhance the bonding between them were also studied. TGA results indicated that silica particles were dispersed uniformly in the PI matrix at the nano-scale level, as observed in SEM images. The coefficient of thermal expansion was decreased by an increase of the silica content.
Enhanced Continuous Glass Fibre-Reinforced Poly(phthalazinone ether sulfone ketone) Composites by Blending Polyetherimide and Polyethersulfone
Authors: Zheng Liang , Jian Xigao
Published: September 2018

Poly(phthalazinone ether sulfone ketone) (PPESK) is a novel high performance thermoplastic with outstanding high temperature resistance and excellent mechanical properties and therefore, it is a very ideal candidate matrix for advanced composites. However, the high melt viscosity of PPESK makes it difficult to melt-process. In this paper, two well-known high performance thermoplastics, polyetherimide (PEI) and polyethersulfone (PES) were introduced into PPESK in order to reduce its melt viscosity and to improve the properties of its composites. The effect of the addition of PEI and PES on the resultant composites was studied. A series of unidirectional composites was made from PPESK and its PEI and PES blends as matrices and continuous glass fibre as reinforcement. The solution prepregging method and hot-press moulding method were used in the preparation of composites. The effects of the polymer blend matrices on the mechanical properties, interfacial adhesion and fracture mode were studied by three point bending, interlaminar shearing, porosity measurements and SEM microscopy. The results showed that the mechanical properties and interfacial adhesion increased and the porosity decreased after blending PEI or PES in the matrix. Addition of PEI and PES to PPESK also resulted in an obvious transition of fracture mode.
Hybrid Fibre Reinforced Epoxy Composites for Pultrusion: Mechanical and Thermal Properties
Authors: Chen Chin-Hsing , Chen Ping-Hung
Published: September 2018

Hybrid glass/carbon fibre reinforced epoxy (GF/CF/Epoxy) composites have been manufactured by pultrusion processes, in order to obtain the best mechanical properties, thermal properties and optimum price of hybrid GF/CF/Epoxy composites for pultrusion. The static mechanical properties including flexural strength, flexural modulus, notched Izod impact strength and swelling ratio, the dynamic mechanical properties including dynamic storage modulus, E’ and tan δ (T), and the thermal properties including of weight loss by TGA of pultruded hybrid GF/CF/Epoxy composites were investigated. The results showed that the flexural modulus increased with the increasing of carbon fibre content. The flexural strength, notched Izod impact strength and swelling ratio of pultruded composites decreased with increasing carbon fibrecontent. The E’ of pultruded composites increased with the carbon fibre content, postcuring temperature and postcuring time. The peak of tanδ for pultruded composites was shifted to a higher temperature when the carbon fibre content, postcuring temperature, and postcuring time were increased. From TGA, the weight loss of pultruded composites decreased with the carbon fibre content, postcuring temperature, and postcuring time in an inert (N2 gas) atmosphere, and the char yield increased with the carbon fibre content, postcuring temperature, and postcuring time. From the SEM morphology, excellent wet-out of the hybrid fibre by the epoxy resin could be observed.
Studies on Analysis and Characterization of Phenolic Composites Fabricated from Lignocellulosic Fibres
Authors: Thakur Vijay Kumar , Singha Amar Singh , Kaur Inderjeet , Nagarajarao Ramkumar Pudukotai , Liping Yang
Published: September 2018

The use of lignocellulosic natural fibres has gained a growing interest during the last few years, principally due to many advantages these fibres can provide in terms of cost, renewability, biodegradability, aesthetic properties, environmental impact etc. Keeping in mind the immense advantages of natural fibres, the present communication is a study on the synthesis and characterization of lignocellulosic Saccaharum cilliare fibre-reinforced polymer biocomposites through compression-moulding technique using phenol-formaldehyde (PF) resin as anovel polymer matrix. The effect of fibre loading on the mechanical, morphological and thermal properties of cellulose fibre reinforced biocomposites has been investigated. Mechanical properties such as tensile strength, flexural strength, compressive strength and wear resistance of fibre-reinforced polymer composites have been investigated as a function of fibre loading. Reinforcing of the polymer resin with lignocellulosic fibres was done in the particle (200 micron) form. The intact polymer biocomposites fabricated showed a common trend of enhancement in the mechanical properties with fibre loadings up to 30%, and beyond this loading the properties decreased. Fibre/matrix interaction has been analyzed by mechanical and morphological (SEM) studies. Thermal (TGA/ DTA/ DTG) studies have also been carried out on the PF matrix, Saccaharum ciliare fibre and particle-reinforced (P-Rnf) biocomposites.
Damage Mechanisms in Hemp-Fibre Woven Fabric Composite, and Comparison with Glass-Fibre Composite
Authors: Bonnafous C. , Touchard F. , Chocinski-Arnault L.
Published: September 2018

This paper deals with hemp-fibre and glass-fibre woven fabric/epoxy composites. The aim is to analyse damage mechanisms in these composites by comparing three different methods: acoustic emission, microscopic observations and stiffness loss measurement. For acoustic emission (AE), an experimental multi-scale analysis was developed in order to identify the different damage mechanisms. Tensile tests were performed on single yarn, neat epoxy resin and composite materials to determine their AE amplitude signatures. A statistical analysis of AE amplitude signals was realised and correlated with microscopic observations. This study has enabled to identify the amplitude and to track, during tensile tests, three types of damage in these composites: matrix cracking, interfacial debonding and reinforcement fracture. It shows the different processes of damage development in natural fibre reinforced composites, in comparison with glass fibre composites. These results were compared to the measured stiffness loss of composites. It allows one to highlight the difficulty to link this mechanical damage parameter with physical AE events.
Environmental Degradation of Starch/Poly(Lactic Acid) Composite in Seawater
Authors: Chen Xiaolei , Wang Lumin , Shi Jiangao , Shi Hang , Liu Yongli
Published: September 2018

In order to study the degradation property of starch/polylactic acid (PLA) composites in a briny environment, injection-moulded tensile bars of starch/PLA composites were investigated by immersion in static seawater controlled at 25 °C for 1 year. SEM micrographs showed that starch particles were lost from the bar because of microbial action. GPC results showed the number average molecular weight ( Mn) of PLA decreased with degradation time. The glass transition temperature (Tg) and melting temperature (Tm) measured by DSC decreased slightly with degradation time. An increase of crystallinity calculated from the DSC data was attributed to the decrease of molecular weight. Weight losses were mainly due to loss of starch. The impact strength of the composites decreased monotonically with degradation time; tensile strength and elongation at break of the composites first decreased, then increased and at last decreased again with degradation time, and the water was acting as a plasticizer. The starch/PLA composites in seawater had degradability, but the degradation rate of composite bars studied in this paper was very slow.
Synthesis and Antimicrobial Activity of Amphiphilic Copolymer Derivatives
Authors: Bai Yongxiao , Liu Yaobin , Li Yanfeng , Changa Caiping , Zhang Qi
Published: September 2018

A series of antimicrobial amphiphilic quaternized copolymers are synthesized through glycidyl methacrylate and styrene after poly(glycidyl methacrylate- co-styrene) modified by introduction of chloroethylic groups using chloroacetyl chloride. The antimicrobial activity of the obtained copolymers was evaluated against the gram-negative bacteria Escherichia coli, the gram-positive bacteria Bacillus subtilus, Staphyloccocus aureus Rosenbach and the fungus Monilia albican by the cut-plug method and Luria-Bertani broth suspended method. The research showed that the copolymer with the molar ratio of monomers 30:70 was the most effective against the microorganisms. The minimum inhibitory concentration (MIC) values of the polymer with against Staphyloccocus aureus Rosenbach and Monilia albican were found to be 31.3 and 32.1 μg/mL, respectively, and these copolymers did not have any haemolytic action for mammalian erythrocytes.
Synthesis and Characterization of Elongated Chain-like Nanostructure Polyaniline in Ice Cube
Authors: Roy Aashis S. , Anilkumar Koppalkar R. , Prasad M.V.N. Ambika
Published: September 2018

Highly crystalline polyaniline (PANI) with elongated chain-like nanostructures 20–35 nm in diameter and 60–80 nm in length were prepared using sodium dodecylbenzenesulfonic acid (SDBSA) in ice medium without stirring. The synthesized polyanilines were characterized by SEM, FTIR, and UV-Visible spectroscopy and XRD measurements. The formation of polyaniline/SDBSA salts insoluble in reaction system without stirring is found to be favourable for the formation of this clustered chain-like nanostructure. The temperature dependent conductivity measurement shows a thermally activated exponential behaviour of the chain-like polyaniline nanostructure. The melting point of the nanostructured polyaniline was found to be 253 °C.
Correlation between Compression-Set and Compression Stress-Relaxation of Epichlorohydrin Elastomers
Authors: Wahab A. , Farid A.S.
Published: September 2018

Set behaviour has always been regarded as an efficient and experimentally facile way of assessing sealing performance. However, many argue that stress-relaxation, which is a little more complicated to assess compared to set, should be the principal property by which sealing behaviour should be ranked. Given the experimental ease with which set can be determined, it is therefore desirable to develop a relationship combining stress-relaxation with the simplicity of compression-set so as to circumvent the need for determining the experimentally arduous property of compression stress-relaxation. Such a relationship will clearly couple experimental convenience with a reliable parameter for assessing sealing behaviour. Thus, the object of the present paper is to investigate the extent to which compression-set results can be used to indicate stress-relaxation behaviour. In this endeavour a mathematical model proposed by Ellul and Southern1 is employed. The overall conclusion is similar to that of other workers who have carried out work of this nature, but notably, it was found that the model was sufficient for ranking purposes.
Investigations on the Evolution of Akron Abrasion Process of SBR Vulcanizates
Authors: Sun J.T. , Hu B. , Zhang P. , Zhao S.G.
Published: September 2018

The Akron abrasion processes of two different kinds of SBR (1502 and T2000R) were studies in detail in this paper. The whole Akron abrasion process (1.61 km) was divided equally into six stages, and the abrasion loss at every stage was measured. The crosslink density and abrasion pattern of every abrasion stage were investigated respectively by Nuclear Magnetic Resonance Crosslink-density Spectrometry (NMR-CDS) and optical microscopy. The effects of hot-air aging and carbon black fraction on the abrasion processes and abrasion resistance are also discussed. For both unfilled SBR1502 and SBRT2000R, it was found that the trend in the plot of abrasion loss against stage number was similar to each other. Their abrasion loss at different stages was different, and it had a maximum value at the third stage. The crosslink density decreased as the number of revolutions increased, while it increased sharply at 6000 revolutions due to the abraded surface being torn off. The microscopic studies showed that the abrasion began at 100 revolutions, and the coarse Schallamach abrasion pattern formed at 1000 revolutions. The ridges here were more or less across the circumference of the specimen. For filled vulcanizates, the abrasion resistance improved as the fraction of carbon black increased. The trend in abrasion loss plot was similar to that of the unfilled samples when the content of carbon black was lower than 30 phr. However, only a slight variation was observed in the abrasion loss at different stages when the content of carbon black was greater than 30 phr.
Optimization of the Mechanical Properties of Abaca Fibre-Reinforced High Impact Polystyrene (HIPS) Composites Using Box-Behnken Design of Experiments
Authors: Agung E.H. , Sapuan S.M. , Hamdan M.M. , Zaman H.M.D.K. , Mustofa U.
Published: September 2018

Mechanical properties of polymer composites are influenced by many factors such as the types of fibres, the types of polymer matrix, the additives used and the adhesion between fibres and polymer matrix. To improve the interfacial adhesion between HIPS matrix and abaca fibres, a study of the optimum use of a coupling agent (MAH) and impact modifier is presented in this paper. Abaca fibre reinforced high impact polystyrene (HIPS) composites were produced with different fibre loadings (30,40 and 50 wt.%), different compositions of coupling agent, maleic anhydride (MAH) (1, 2 and 3 wt.%) and different compositions of impact-modifier (4, 5 and 6 wt.%). A response surface methodology using Box-Behnken design was used in the design of experiments and analysis of results. Statistical analysis of mechanical properties gave very satisfactory model accuracy, because the coefficient of determinance was 0.9817 for impact strength, 0.9789 for tensile strength, 0.9672 for tensile modulus, 0.9700 for flexural strength, and 0.9747 for flexural modulus. In this study, a loading of abaca fibre of 36.76 wt.%, maleic anhydride 3 wt.%, and impact modifier 4 wt.% led to optimum individual impact strength. On the other hand, optimum individual tensile strength and tensile modulus were achieved when the loading of abaca fibre was close to 40.76 wt.%, maleic anhydride 3 wt.% and impact modifier 6 wt.%, but the optimum individual flexural strength and flexural modulus were found when the loading abaca fibre was close to 40.03 wt.%, maleic anhydride 3 wt.% and impact modifier 4 wt.%.
A Statistical Study of Fatigue Life Prediction of Fibre Reinforced Polymer Composites
Authors: Seyhan A. Tuğrul
Published: September 2018

In this study, the tension-tension fatigue response of bidirectional woven E-glass fibre reinforced unsaturated polyester composites was experimentally determined. The composite parts were produced via continuous laminating process. The probabilistic fatigue life distribution of the produced composites at various constant stress levels was then modelled, based on the two-parameter Weibull approach. A variety of different methods including graphical, method of moments and the maximum likelihood were conducted to predict the Weibull parameters. For the sake of reliability, the composite fatigue life data gathered at each constant stress level were correlated with the approvals of Kolmogorov-Smirnow goodness-of-fit test. Furthermore, the two parameter Weibull approach was utilized to relate the composite failure probability to the number of fatigue cycles that the composite withstands under a given load. As a result, the two-parameter Weibull approach has proved to be an efficient statistical tool to assess the reliability of polymer composite structures.
The Influence of Engineered Calcium Carbonate Functional Additives on the Mechanical Properties and Value Proposition of Polyethylene Films
Authors: Whiteman D.J. , Agra-Gutierrez C. , Bird M.J. , Thomas S.E. , Skuse D.R. , Ansari D.M.
Published: September 2018

The current study considers the use of a selection of engineered ground calcium carbonates in two different polyethylene film systems. The calcium carbonate grades selected cover a range of particle sizes and include uncoated and organically treated examples. Alterations in the processing requirements on mineral addition are reported and their implications for film and masterbatch production considered with respect to energy usage and throughput. Inclusion of the engineered additives allowed production of the same weight of material at lower energy uses or improved productivity at the same energy usage. The effects on the mechanical properties of the composite films with increasing mineral loading have also been measured, demonstrating enhancements particularly in the areas of tear strength and impact resistance. These enhancements allow the possibility of film downgauging relative to the unfilled film without loss of performance and yield a raw material cost saving by reduction of polymer usage.
Synthesis and Characterization of New Diimide Diols and Processable Poly(esterimide)s Derived Therefrom
Authors: Thiruvasagam P. , Shiva C. , Sundararaman C. , Venkatesan D.
Published: September 2018

New aromatic diimide-diol monomers were prepared by the aromatic nucleophilic substitution reaction of aromatic dianhydrides and 4-aminophenol/(4-aminophenyl)-2'-(4-hydroxy phenyl)propane. The monomers were characterized by IR and 1H-NMR spectroscopy. A series of poly(esterimide)s was prepared from diimide-diols and aromatic diacid chlorides by solution polycondensation reaction in N-methyl-2-pyrrolidone. The poly(esterimide)s were characterized by IR and 1H-NMR spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, gel-permeation chromatography, solution viscosity and solubility behaviour. The poly(esterimide)s with flexible groups, methyl groups and 1,3-disubstituted phenyl rings in the chain were expected to disturb the symmetry, and their effects on the property were studied. Most of the poly(esterimide)s exhibited good solubility in common organic solvents. The poly(esterimide)s displayed good thermal stability, and the 10% weight loss under nitrogen atmosphere ranged from 361 to 439 °C respectively.
Mechanical Properties of Kevlar-49 Fibre Reinforced Thermoplastic Composites
Authors: Yeung K.K. Herbert , Rao K.P.
Published: September 2018

Conventional materials made of glass and carbon fibres in thermoset resins are very frequently employed. Recently, thermoplastic matrix composites are being developed to improve the toughness and damage tolerance of composite laminates. The ductility of thermoplastic resins implies a more pronounced plasticity in service. Kevlar fibre has a tensile strength comparable with that of carbon fibre, a modulus between those of glass and carbon fibres and a lower density than both. Kevlar-49 reinforced composites are increasingly demanded in a variety of commercial applications but their understanding is relatively new when compared to traditional fibres. Simple micromechanics based models such as the rule of mixtures, inverse rule of mixtures (ROM), Halpin-Tsai and Xu-Reifsnider models are employed to predict the mechanical properties of Kevlar-49 fibre composites formulations. In this study, the mechanical properties including tensile, compressive and flexural strength and modulus of Kevlar-49 thermoplastic based composites were experimentally obtained and compared with the theoretical predictions. A systematic costing analysis of respective thermoplastic composites has been made for the provision of composite selection guidelines for designers.
Compression and Recovery Behaviour of Polyamide-6 Based Foams
Authors: Izzard V.G. , Hadavinia H. , Morris V.J. , Foot P.J.S. , Wilson L. , Hewson K.
Published: September 2018

This paper presents experimentally determined compression sets and compression behaviour of two closed-cell, crosslinked foam materials; ZOTEK N B50 (Nylon 6) and ZOTEK N A30 (nylon/polyolefin alloy). This work forms the basis of future investigations into the post-impact behaviour of these foams.

Compression set performance was measured at 25.0, 37.5 and 50.0% strain at nine temperatures ranging from −5 to 90 °C. Compression tests at constant strain rates were conducted at four temperatures between 23 to 90 °C. Finally compression tests at 23 °C were repeated at four strain rates between 0.3 and 550 hr−1 to determine strain rate dependency. The Nagy and Williams-Landel-Ferry scaling factor for strain rate and temperature were applied to the experimental results and equations were derived which allowed the performance of the two polyamide based foams to be interpolated over the strain rate and temperature range of study. The required material properties of interest of the base polymers have been assessed and are presented and discussed in relation to the performance of the foam materials.
Preparation and Characterization of Nanocomposites based on Poly(ε-caprolactone) and the Surface Grafted Nanohydroxyapatite with the Comb-shaped Poly(ε-caprolactone) Brushes
Authors: Fu Guoxin , Zeng Liang , Jiang Jianwei , Xia Zhixiang , Jing Bo , Zhang Xuefei
Published: September 2018

Surface modified hydroxyapatite/poly(ε-caprolactone) composites with comb-shaped poly (ε-caprolactone) (PCL) brushes grafted hydroxyapatite (n-HAP) were synthesized by a combination of atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP).,. Compared to the corresponding unmodified n-HAP/PCL composites, at modified n-HAP contents of 15 wt.% and 20% with a grafting ratio of 26.32%, the composites showed a maximum tensile modulus and elongation at break, flexural modulus and bending strength, respectively. This suggested that the comb-shaped PCL brushes at the interface are of advantage to the improvement of interfacial adhesion between the n-HAP and PCL polymer matrix by chain interdiffusion and entanglement with the PCL matrix. Furthermore, the observation should be attributed to the modified n-HAP particles, which were uniformly distributed in the polymer matrix and acted as heterogeneous nucleating agents during the crystallization of the PCL matrix.
New Photosensitive Polyamide/Organoclay Nanocomposite Prepared by a Solution Dispersion Technique
Authors: Shabanian Meisam , Faghihi Khalil
Published: September 2018

Photosensitive polyamide/layered silicate nanocomposites (PAN) were prepared via a solution polymerization process from polyamide 3 containing chalcone moieties and organo-MMT in a solution of N,N-dimethylacetamide. Incorporation of small amounts of an organoclay can reduce the coefficient of thermal expansion (CTE) of photosensitive polymer formulations (photoresists). The organoclay was examined for its dispersion behaviour in the polyamide matrix. Polyamide chains were synthesized from 4,4'-diaminochalcone 2 and terephthaloyl chloride (TPC) in dimethylacetamide. These amide chains were selectively end-capped with carbonyl chloride end groups to interact chemically with modified montmorillonite clay. The resulting composite films containing 5–15 wt.% of organoclay were characterized by SEM, XRD, TGA, DSC and water absorption measurements. The distribution of organoclay and nanostructure in the composites was investigated by XRD and SEM analyses. The photosensitive properties of the polyamide 6 in the DMF solution were studied by UV spectrophotometry. The nanocomposites exhibited increases in their glass transition temperatures relative to pristine polyamide, implying interfacial interactions between the two phases. The percentage water absorptions of the polymers were found to be much reduced upon the addition of modified layered silicates indicating decreased permeability.