bluuebunny/crossref_metadata_2025 huggingface dataset:
The Hidden Benefits of Facilitated Dialogue
Authors: Milz Dan
Published: September 2018

Studies of alternative dispute resolution demonstrate how interest-based tradeoffs contribute to joint gains, yet facilitators do more than just broker deals between adversaries. This paper explores how facilitation supported the development of a regional wastewater plan on Cape Cod, Massachusetts. Coded video records unearth the judgments stakeholders and facilitators made as they accounted for spatial scale mismatches between towns and watersheds. The findings demonstrate how facilitators supported the conceptual work of nonexpert stakeholders highlighting several tactics they used to support cross-scale reasoning. The findings allude to a new set of conversational techniques for planners and facilitators in practice.
Dynamic Mechanical and Thermal Analysis of Reactive Poly (Butadiene-Co-Acrylonitrile) Rubber-Modified Polybenzoxazine Resin
Authors: Ishida Hatsuo , Lee Yu-Hsin
Published: September 2018

An amine-terminated butadiene-acrylonitrile copolymer (ATBAN) was introduced to polybenzoxazine by the modification of monomer prior to curing. After the thermally induced ring-opening reaction, a mixture of two network structures was formed. Dynamic mechanical analysis (DMA) was used to study the relaxation behaviour in different temperature regions and thermal properties of the modified system were examined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
Impact Damage Resistance of Carbon Fibre/Epoxy Composite Laminates Containing Short Kevlar Fibres
Authors: Sohn Min-Seok , Hu Xiao-Zhi , Kim Jang-Kyo
Published: September 2018

The impact damage resistance of carbon fibre/epoxy matrix composites containing short Kevlar® fibres as the interlayer material was studied. Instrumented low-velocity impact tests were conducted at several temperatures to study the impact fracture and damage mechanisms. The experimental results indicate that short Kevlar fibres improved the impact damage performance. Distinct damage patterns were observed on the front and back faces of the specimens tested at two extreme temperatures; -60°C and 130°C. Cross-sectional microscopy was performed to evaluate sub-surface damage; optical and scanning electron microscopy were used to study the fracture mechanisms of the laminates impacted at different temperatures. The main contribution of the interlayer material to the improvement in impact resistance was the enhanced fibre-bridging with the short Kevlar fibres at the interlaminar regions.
Interactions between Surface Treated Ultrafine Mineral Filler and Silicone Rubber Matrix
Authors: Wu Jihuai , Shen Zhen , Wei Congrong , Chen Yike , Hu Donghong
Published: September 2018

Silicone rubber filled with surface treated ultrafine mineral powder was prepared. The bound rubber in uncured silicone rubber was investigated using different mineral powders as fillers. The cross-link density in the vulcanizate was researched, and the mechanical properties were measured. It was found that there are strong relationships between BRT (bound rubber in toluene solvent), DT (total cross-link density) and tensile strength for vulcanizate. There are also strong links between BRE (bound rubber in basic solvent), DC (chemical cross-link density) and 100% modulus for vulcanizate. Mean while, the bound rubber, cross-link density and mechanical properties of the silicone rubber products are affected by the surface chemical treatment of the mineral filler.
Rf Plasma Polymerisation for the Improvement of Interfacial Adhesion between Glass Fibres and Polybutene-1
Authors: Chou Shen , Shih Kan-Shan , Chen Shuh-Heng
Published: September 2018

Radio frequency (RF) plasma polymerisation is used to treat glass fibres to improve the interfacial adhesion between polybutene-1 and glass fibre. After the glass fibres were treated with coupling agent, four different monomers were polymerised onto the surface by plasma. The plasma polymers changed the surface morphology and surface free energy of the fibre surfaces. The experimental results indicate that a grain-like surface induces a transcrystalline layer to form onto the fibre surface to improve the polybutene-1/glass fibre interfacial shear strength relative to glass fibres treated with coupling agent only. The glass fibre treated with coupling agent, then treated with acrylonitrile and styrene increased the interfacial adhesion strength by 71% and 78%respectively. Glass fibre surfaces treated with grain-like organosilicon, then plasma polymerised tetramethylsilane (ppTMS) and hexamethyldisiloxane (ppHMDSO), allow a transcrystalline layer to form and this increases the interfacial shear strength by 187% and 180% respectively, achieving 100% and 97% higher strength than when treated with coupling agent only.
Aromatic Block Copolyesters Stabilised with Metallic Salts of Phosphinic Acid
Authors: Ozden S. , Shaov A. H. , Charayev A. , Mikitaev A. K. , Bedanokov A. Y.
Published: September 2018

Stabilisers consisting of metallic salts of p-butoxyphenylcyclohexyl phosphinic acid were introduced into two industrial copolymers based on bisphenol-A and phenolphthalein respectively, and their effects on the mechanical and thermal properties were investigated. The mechanical properties were sensitive to the amount of stabiliser. Ductility and breaking strength increased with small additions, but as the amount of stabiliser increased, the process was reversed. On the other hand the modulus of elasticity showed a steady decrease. Similarly, the thermal stability also increased with small concentrations of additive, and decreased at higher concentrations. Heat treatment increased the brittleness and reduced the breaking strength.
Properties of Metal Fibre Filled Thermoplastics as Candidates for Electromagnetic Interference Shielding
Authors: Tan Song Ting , Zhang Ming Qiu , Rong Min Zhi , Zeng Han Min , Zhao Fang Ming
Published: September 2018

Polypropylene (PP) based conductive composites were produced using stainless steel fibres (SSF) as the fillers. Their mechanical properties, electrical conductivity and electromagnetic interference (EMI) shielding effectiveness were measured. For the purposes of performance optimization, polypropylene grafted maleic anhydride copolymer (PP-g-MAH) was added. The results indicate that when PP was replaced by PP-g-MAH, the mechanical properties of the composites can be improved, but the conductivity decreased remarkably. However, a positive synergistic effect was found in the case of SSF/PP-g-MAH/PP, which was characterized by acceptable strength and modulus as well as by an EMI attenuation ability of 30dB.
Evolution of Damage Zone in Adhesive Layer of Adhesively Bonded Butt Joints under Cyclic Loading
Authors: Imanaka Makoto , Turui Takafumu , Akizuki Yojirou
Published: September 2018

For rubber-modified adhesives, the damage zone plays an important role in governing adhesive strength. Recently, the damage to the adhesive layer has been investigated by in-situ observation under several load conditions. However, these observations are limited to the behaviour on the surface of the adhesive layer. If an adhesively bonded butt joint with a very thin adherend can be tested, damage in the interior of the adhesive layer will be observed in transmitted light, which facilitates clarification of the fracture mechanism of adhesive joints. In this study, to observe the damage in the interior of the adhesive layer, adhesively bonded butt joint specimens were made from 0.3 mm thick steel plates bonded by a rubber modified adhesive. These specimens were used for the fatigue tests, and the damage to the adhesive layer was examined by use of a microscopic video-camera under transmitted light. Furthermore, elastic-plastic finite element analysis of the butt joint was conducted to simulate the propagation behaviour of the damage zone. Modified Gurson's constitutive equations were applied to the adhesive layer and the rubber particles were considered to be the initial voids. The result for the analytical distributions of the void volume fraction was compared with the observed damage zone. It was found that the observed damage zone coincides with the high volume fraction zone.
Interferometric Determination of Orientation and Some Optical Parameters of annealed Polyester Fibres
Authors: Fouda I.M. , El-Sharkawy F.M.
Published: September 2018

Multiple-beam Fizeau fringes in transmission have been applied to annealed PET fibres, to determine the refractive indices of their skin and core layers for plane polarized monochromatic light at λ =546.1 nm, vibrating parallel and perpendicular to the fibre axis. We obtained the optical orientation parameters by applying the equations used by Hermans and Ward. Some structural parameters such as electric polarizability were determined. The density of the samples studied was measured by a system based on the theory of vibrating strings.

The density and optical results were used to calculate the degree of crystallinity, the mean square density fluctuation, the form birefringence, the number of monomeric units per unit volume, the harmonic mean polarizability of the dielectric, and the harmonic mean specific refractive index.

The generalized Lorentz-Lorenz equation given by de Vries was used to determine the structural parameters of annealed PET fibres. Comparisons between the experimental results and those obtained by using the Lorentz-Lorenz and Hermans equations are given. Refractive index profiles are also given. The results show the new reorientation and layer changes accompanying annealing under different conditions. Illustrations are given of multiple-beam microinterferograms in transmission.
Repairing Broken Thermoset Pieces Using Diffusional Pretreatment and Cure with Uncured Resin
Authors: Abdelouahab J. Ben , Bouardi A. El , Granger R. , Vergnaud J.M.
Published: September 2018

Repairing broken thermoset pieces is often carried out, although optimization of the technique may not have been achieved. A new way is investigated using a thermoset based on an unsaturated polyester resin allowing the final product to exhibit good mechanical properties. The procedure described here consists of two stages: putting some pure resin on the surface of the broken thermoset piece over a given a period of time, then putting this pre-treated piece in the mould with fresh uncured thermoset (made of pure resin with fibreglass and filler) necessary to fill the mould, and curing this system. The pre-treatment with the pure resin is made on the surface of the broken thermoset piece which will be in contact with the fresh uncured thermoset. The mechanical properties in elongation and flexion of the final material are measured. It appears that not only the diffusion of pure resin into the broken thermoset is responsible for an increase in these mechanical properties, but also that the time of diffusion is of interest, 24 h being better then 4 h. With a time of diffusion of 24 h, the mechanical properties are nearly similar to those obtained with the original non broken thermoset piece.
Analysing the Content of Antioxidants in PP Materials
Authors: Schroeder H. F. , Zeynalov E. B. , Bahr H. , Rybak Th.
Published: September 2018

The effective stabilisation of polypropylene (PP) plastics for durable applications is often achieved by compounding with a combination of hindered phenolic (SHPh) and amine (HAS) antioxidants. Hence, to assess the lifetime of these materials it is useful and often necessary to test the status of each type of stabiliser used during or after exposure. In this paper, we discuss the measurement of the steady-state rate of post-induction oxygen consumption during the model reaction of initiated cumene oxidation. This is in order to determine antioxidants of the HAS type derived from 2,2.6,6-tetramethylpiperidine. As already published, the measurement of the induction period can be used for the simultaneous determination of the SHPh content. The rate of the post-induction oxidation reaction depends linearly on the reciprocal square root of the concentration of this HAS-antioxidant type, for a sufficiently wide concentration range. The presence of sterically hindered phenolic stabilizers (SHPh) and organophosphites usually of the kind used has no influence on this post-induction phase. Thus the dependence established offers a remarkable possibility of determining simultaneously the effective stabiliser concentrations of the HAS and SHPh antioxidants by means of one model reaction. We present the results of the successful determination of a HAS and an SHPh antioxidant in PP granules. They have to be ground down to particles with mean dimensions smaller than 250 μm. We found perfect coincidence with the data given by the granule producer.

Thus the model reaction of initiated cumene oxidation is a useful method for the simultaneous quantitative study of SHPh and 2,2.6,6-tetramethylpiperidine derived HAS-antioxidants, even in the presence of organophospites in PP, and possibly other plastics.
Influence of Hybridisation and Test Geometry on the Impact Response of Glass-Fibre-Reinforced Laminated Composites
Authors: Schrauwen Bernard , Bertens Pascal , Peijs Ton
Published: September 2018

This paper describes the results of falling weight impact tests (FWITs) on glass-fibre-reinforced (GRP) laminates and E-glass/Dyneema® hybrid laminates. The test programme consisted of (i) falling weight impact tests to determine the penetration energy and (ii) experiments to determine the influence of hybrid construction on damage development and impact fatigue lifetime under repeated impact conditions at sub-penetration energy levels. The objective of this work was to investigate the effect of hybridisation on the impact behaviour of GRP laminates as well as to find optimal conditions for hybridisation. It was shown that in the case of a rigid test set-up - and hence small deflections - the influence of the Dyneema® on the impact behaviour of hybrid laminates is rather small because damage processes are the result of local contact stresses in the vicinity of the impact body, whereas in the case of a compliant test set-up and large deflections the high energy storage capacity of the ductile Dyneema® fibres is used far more effectively for the protection of hybrid composite laminates. Therefore, it was concluded that in order to fully utilise the potential of high-performance polyethylene fibres it is essential that these fibres are located on the (non-impacted) tensile side of an impacted laminate and that the geometrical test conditions are such that large (bending) deformations are allowed.
Matrix Cracking and Delaminations in Orthotropic Laminates Subjected to Freeze-Thaw: Model Development
Authors: Roy Samit , Nie G.H. , Karedla R. , Dharani L.
Published: September 2018

With the increasing use of fibre composites in applications such as cryogenic liquid hydrogen tanks and repair/retrofitting of bridges, the diffusion and freezing of moisture to form ice is an issue of growing importance. The volumetric expansion of water when it freezes to form ice results in stress concentrations at the inclusion tip that may synergistically interact with the residual tensile stresses in a laminate at low temperatures to initiate a crack. In addition, understanding the long-term effect of daily and/or seasonal freeze-thaw cycling on crack growth in a laminate is of vital importance for structural durability.

The objective of this paper is to establish a theoretical framework for the calculation of the stress intensity factor (KI) of a pre-existing crack in a composite structure due to the phase transition of trapped moisture. The constrained volume expansion of trapped moisture due to freezing is postulated to be the crack driving force. The principle of minimum strain energy is employed to calculate the elastic field within an orthotropic laminate containing an idealized elliptical elastic inclusion in the form of ice. It is postulated that a slender elliptical elastic inclusion can be used to approximate the stress field at the crack face, which can subsequently be used to calculate the stress intensity factor, KI, for the crack. The verification of the analytical model predictions and some potential applications will be published in a separate paper.
Mechanical Properties and Microstructure of the HDPE/Al(OH)3/POE Composite
Authors: Yang Jinhai , Zhang Yong , Zhang Yinxi
Published: September 2018

The effect of ethylene-octene copolymer (POE) and maleic anhydride grafted ethylene-octene copolymer (POE-MH) on the mechanical properties, especially the toughness, of highly filled HDPE/Al(OH)3 composites was studied. POE has hardly any effect on the toughness of the composites, but, POE-MH can improve it remarkably. The microstructure of the ternary phase composites was explored by SEM, DMA, and DSC. An encapsulation structure was obtained when POE-MH was used, and a phase-separated structure was obtained when POE was used.
Mechanical Properties of Sisal Reinforced Composites in Response to Water Absorption
Authors: Rong Min Zhi , Zhang Ming Qiu , Liu Yuan , Zhang Zhi Wei , Yang Gui Cheng , Zeng Han Min
Published: September 2018

The authors discuss the water absorption behaviour of sisal and its epoxy based composites and the mechanical properties of composites that have been aged in water. In addition, a series of fibre pretreatment techniques, including mercerization, acetylation, cyanoethylation, coupling agent treatment and thermal treatment, which are believed to be able to improve the water resistance of sisal and its composites, have been evaluated. It was found that the water absorption behaviour of sisal composites is controlled mainly by the fibre and the fibre/matrix interfacial characteristics. As a result, appropriate fibre modification to retard water diffusion and enhance interfacial adhesion is necessary if the natural fibre composites are to be used in practical applications.
Glass Fiber Reinforced Composites of Coloured Epoxy Resin Cured with Different Amines
Authors: Patel Milan R. , Patel Manish P. , Patel Rashmika H. , Patel Ranjan G.
Published: September 2018

A novel coloured epoxy resin has been synthesized by reaction between epichlorohydrin and bisazodiol. The curing of the resin, blended with a DGEBA resin, were characterized by differential scanning calorimetry (DSC). The thermal stability of the cured products has been investigated by thermogravimetric analysis (TGA). The cured products showed good thermal stability. Glass fibre composites were fabricated by blending a DGEBA resin and the novel coloured epoxy resin and their mechanical properties, electrical properties and chemical resistance were studied.
Polyolefin Composites Filled with Magnesium Hydroxide
Authors: Zhu Song , Zhang Yong , Zhang Yinxi
Published: September 2018

In this study, modified and non-modified composites of polypropylene (PP) and linear low-density polyethylene (LLDPE) filled with magnesium hydroxide (Mg(OH)2) were investigated, and maleic acid anhydride-grafted PP or LLDPE (MAH-g-PP, or MAH-g-LLDPE) were used as polymer modifiers. In the composites, when the LLDPE was partially replaced by MAH-g-LLDPE, the notched Izod impact strength, tensile strength, and flexural strength of the composites increased, while the modulus decreased. When the PP was partially replaced by MAH-g-PP, the tensile strength and flexural strength of the composites increased, and the impact strength and modulus changed slightly. The phase structure of the composites was characterized using scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), and differential scanning calorimeter (DSC).
Complete In-plane Elastic Characterisation under Tensile Tests of Angle-Ply Laminates Composed of Polymer-Matrix Layers
Authors: Valot E. , Vannucci P. , Verchery G.
Published: September 2018

In this paper we present a new strategy to completely characterise the in-plane elastic properties of a large range of angle-ply laminates using only unidirectional tests. We consider laminates having the same number of identical plies in the α and – α directions. This new method uses some preceding results found by Verchery for orthotropic laminates, namely the conditions of existence of a specific direction ω, in which the shear-extension coupling is null. The characterisation of the laminate is then made using the results of three tensile tests: two in the orthotropy axes, and the third one in the ω direction, in order to have always a pure one-dimensional state of stress. We show that for the most common unidirectional fibre-reinforced materials, the angle ω is, in most cases, close to the α direction of the fibres. This result permits a complete experimental characterisation of the laminate, which then does not need any a priori knowledge of the elastic properties of the elementary layer. In addition, it provides a simple method to verify the predictions of the laminate behaviour obtained by the Classical Laminated Plate Theory (CLPT) when the elementary layer is completely known. The paper ends with numerical examples and with the results of some experimental tests.
Graft Polymerization of Vinyl Monomers onto Nanosized Silicon Carbide Particles
Authors: Ji Qiu Long , Rong Min Zhi , Zhang Ming Qiu , Friedrich Klaus
Published: September 2018

For the purpose of preparing polymer composites filled with SiC nanoparticles to be used in tribological applications, grafting polymerization onto the particles was carried out as a way of surface modification. It is believed that the interfacial interaction in the composites can be tailored in this way. The SiC surface was pre-treated with a silane coupling agent, followed by radical grafting polymerization of acrylamide and styrene, respectively. Infrared spectroscopy and measurement of dispersiveness in solvent demonstrate that the desired polymer chains have been covalently bonded to the surface of the nanoparticles. In addition, the polymerization conditions were investigated and the controlling factors were established accordingly.
Stress Intensity Factor for an Elliptic Inclusion in Orthotropic Laminates Subjected to Freeze-thaw: Model Verification
Authors: Roy Samit , Nie G.H. , Karedla R. , Dharani L.
Published: September 2018

Verifications and applications of an analytical model developed previously for the calculation of mode-I stress intensity factor of a pre-existing crack in an orthotropic composite structure due to the phase transition of trapped moisture are presented in this paper. The verifications are based on comparisons of the stresses in an elliptic elastic inclusion and the stress intensity factor with a special case of isotropy (for which there exists an analytical solution) and with finite element analysis for the case of orthotropy. The results indicate that the stress state in a slender elliptic elastic inclusion can be used to approximate the stress field at the crack face, which could subsequently be adopted to determine the stress intensity factor. Analyses of the delamination and fatigue life prediction for freeze-thaw cycling are provided as specific applications of the model.
Effect of Heat Treatment on the Impact Strength of Glass Fibre Reinforced Polypropylene
Authors: Lin Jeng-Shyong
Published: September 2018

The improvement of the interfacial adhesion of glass fibre reinforced polypropylene composites by heat treatment was studied. Polypropylene blended with short glass fibres was injection moulded. The moulded specimens were heat treated at various temperatures and for various times. Characterization of the mechanical properties of the samples was performed, including measurement of the critical fibre length. Impact tests were performed. The fracture surfaces were examined using a scanning electron microscope. The results show that the impact strength increased with the testing temperature. At 25°C, the impact strength was dominated by the fibre fracture mechanism. At temperatures above 120°C, it was strongly influenced by the PP matrix. At higher temperatures, the impact strength increased significantly because of the formation of extra cracks.
Rheological and Mechanical Properties of PC/HDPE/glass fiber Composites
Authors: Li Chaoqin , Zhang Yong , Zhang Yinxi , Zhang Changming
Published: September 2018

The rheological behaviour and mechanical properties of the polycarbonate/high density polyethylene/glass fiber (PC/HDPE/GF) composites have been studied, along with fiber-resin interface behaviour. Maleic anhydride grafted low density polyethylene (LDPE-g-MAH) was used as a compatibilizer in the composites. A study of the glass fiber-resin interface by scanning electron microscopy (SEM) and by etching techniques indicated that the dispersed phase polymer in the composites preferentially adhered to the glass fibers in the absence of LDPE-g-MAH. For the composites containing LDPE-g-MAH, this resin might play a decisive role in the adhesion of polymers to glass fibers. The types of adhered polymers were independent of PC/HDPE ratio. The rheological behaviour was studied using a capillary rheometer. The results showed that there was little relationship between the viscosities of the components and the types of polymer adhered to glass fibers. There was a critical shear rate at about 100s−1 for the viscosities of the composites. At shear rates lower than 100s−1, the glass fibers increased the viscosity of the composites; at shear rates higher than 100s−1, the glass fiber had little effect on the viscosity. The composites had a good balance of mechanical properties compared with PC/HDPE blends and PC/GF binary composites. LDPE-g-MAH in the composites could improve the reinforcement efficiency of the glass fibers and strengthen the adhesion between polymer matrix and glass fibers.
Durability of Glass-Fibre Reinforced Polymer Composites in Aqueous and High Temperature Environments
Authors: Ellyin Fernand
Published: September 2018

In this investigation glass-fibre/epoxy-resin laminates with [±45, 903]s lay-ups were immersed in distilled water at different temperatures. In particular, three sets of coupon specimens were exposed for about 2 years to varying histories consisting of dry conditions or immersion-dry-out-and-re-immersion treatments, while keeping the temperature constant for each set. Moisture absorption behaviour and the effect of the environment and temperature on the mechanical properties were determined. It was found that there was a strong synergy between temperature and environment. Immersion in distilled water at ambient temperature did not affect the mechanical properties, on the contrary, it increased the threshold strain to crack initiation. However, specimens immersed at T>50°C showed deterioration in all respects. Exposure to cycles of wet and dry conditions at high temperatures were the most damaging environment. The underlying damage mechanisms and microscopic causes leading to the deterioration of the mechanical properties are discussed.
Weldlines in Injection-Moulded Reinforced Thermoplastics: Mechanical Performance Improvement through Intrusion Induced Fibre Reorientation
Authors: Debondue E. , Fournier J.-E. , Lacrampe M.-F. , Krawczak P.
Published: September 2018

The effect of processing conditions on the mechanical properties of a weldline in short glass fibre reinforced polypropylene was investigated. It appears that the presence of a weldline has a deleterious effect on the tensile properties, with a serious loss of strength and rigidity. The optimisation of the process parameters through a Taguchi methodology showed some improvement, the properties remaining however quite distant from those of specimens without weldline. The analysis of the fibre arrangement around the weldline gave clues to explain this situation. In the vicinity of the weldline, the typical skin-core structure was deeply disrupted with a skin layer almost non-existent. Therefore, most of the fibres were oriented perpendicularly to the direction of loading, resulting in poor load transfer. Calculations showed that the strength was almost reduced to the transverse resistance of a unidirectional composite because of the very specific orientation of the fibres around the weldline. The generation of a back-flow in the melt, thanks to a differential gate solidification, brought some reorientation of the fibres and some increase in the properties.
Thermal Properties of Novel PMR Polyimides Prepared by Copolymerisation
Authors: Zhang Zuo Guang , Li Min , Pan Yi Shan , Sun Zhi Jie
Published: September 2018

A novel PMR-type polyimide based on 3,3′4,4′-oxydiphthalic dianhydride (ODPA), 4,4′-methylenedianiline (MDA) with nadic ester (NE) endcaps was studied. Its random copolymers, which incorporated pyromellitic dianhydride (PMDA) and p-phenylenediamine (PPD) into the backbone, were synthesised. They are characterised in abbreviation as OPM (ODPA/PMDA-MDA) and OMP (ODPA-MDA/PPD) respectively. Oligomers with various molecular weights and components were synthesised, in order to compare the influence of the chemical structure and the crosslink density of polyimides on the final properties. MOPM, which contained an identical backbone to OPM but was terminated with a mono-nadic endcap, was also synthesised to see whether the different endcaps of oligomers could impact enhanced thermal properties. The thermo-oxidative stability, processing and mechanical properties of these polyimides were tested. The results showed that incorporation of PMDA or PPD into the ODPA-MDA homopolyimide (abbreviated as OM) could greatly enhance the Tg, while retaining comparable thermo-oxidative stability and reasonable processing properties.
Effect of β-Cyclodextrin on the Dispersion Synthesis of PMMA Particles
Authors: Songjun Li , Jie Hu , Bailing Liu
Published: September 2018

A preliminary investigation into the effect of β-cyclodextrin (CD) on the dispersion synthesis of poly(methyl methacrylate) (PMMA) particles is presented. CD appears to play an important role in the polymerisation, decreasing the particle size and increasing the conversion of the monomer. These effects were evident with an increase in the CD content, but they were not a simple function of CD content. Other factors, such as the unique structure of CD and the interaction between CD and the poly (vinyl pyrrolidone) (PVP) used as stabiliser, appear to be important influences on this polymerisation.
Stabilisation of 3D Preforms with Thermoplastic Monofilament for Advanced Composite Manufacture
Authors: Rogers P.P.J. , McIlhagger A.T. , McIlhagger R. , Quinn J.
Published: September 2018

This paper discusses the stabilisation of three-dimensional woven carbon fibre preforms. A polyethylene monofilament has been incorporated within the structure during weaving and, by the application of temperature and pressure, it has been used to consolidate the edges of carbon fibre preforms. Upon testing the plastic was found to have had a positive effect on maintaining the stability of the preform. Impregnation of modified preforms was undertaken by Resin Transfer Moulding (RTM) in order to assess mechanical properties. The properties of composites specifically made from modified preforms were comparable with those of a conventional composite.
Interacting Blends of Novel Unsaturated Polyester Amide Resin with Methyl Methacrylate
Authors: Patel Hasmukh. S. , Panchal Kumar. K.
Published: September 2018

Novel unsaturated poly (ester-amide) resins (UPEAs) were prepared by the reaction between an epoxy resin, namely diglycidyl ether of bisphenol–A (DGEBA) and unsaturated aliphatic bisamic acids, using a base catalyst. These UPEAs were then blended with a vinyl monomer namely, methyl methacrylate (MMA) to produce a homogeneous resin syrup. The curing of these UPEAs-MMA resin blends was carried out by using benzoyl peroxide (BPO) as a catalyst and was monitored by using a differential scanning calorimeter (DSC). The glass fibre reinforced composites (i.e. laminates) of this UPEA-MMA resin blends were fabricated using the DSC data. The chemical, mechanical and electrical properties of the glass fibre composites have also been evaluated. The unreinforced cured samples of the UPEA-MMA resin blends were also analysed by thermogravimetry (TGA).
Effect of γ-Irradiation on the Properties of Rubber-Based Conductive Blend Composites
Authors: Madani M.
Published: September 2018

The influence of γ-irradiation on the electrical, swelling and mechanical properties of cross- linked butyl (IIR) rubber and ethylene propylene diene monomer (EPDM) and their blends have been investigated. The modulus increased, while the elongation at break decreased with irradiation. The gap width between carbon-carbon particles is found to be highly affected by the irradiation dose, which in turns influenced the electrical conductivity of these blends. The swelling equilibrium data in different solvents were analyzed by the Flory-Rehner equation to obtain estimates of the average molecular weight and cross-link density.
Effects of Trans-Esterification Stabilizers on Mechanical Properties and Structure of Poly(butylene terephthalate)/Polycarbonate Blends
Authors: Bai Huiyu , Zhang Yong , Zhang Yinxi , Zhang Xiangfu , Zhou Wen
Published: September 2018

The effects of triphenyl phosphite (TPPi) and disodium diphosphate (DSDP) on the trans-esterification between poly(butylene terephthalate) (PBT) and polycarbonate (PC) in melt mixing and the mechanical properties of PBT/PC blends were studied. The experimental results showed that the Vicat temperature of the blends increased because of the addition of TPPi or DSDP. DSDP had little effect on the mechanical properties of the toughened PBT/PC blends containing poly(ethylene–butylacrylate-glycidyl methacrylate) (PTW) as toughener, and TPPi led to a decrease in the notched Izod impact strength of the toughened PBT/PC blends. DSDP was confirmed to be an effective stabilizer for the trans-esterification of PBT and PC, using the methods of Fourier Transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and solvent extraction.
Multi-Response Optimization of PC/ABS Blends Using Principal Component Analysis
Authors: Fung Chin-Ping , Kang Po-Chung
Published: September 2018

This paper reports the multi-response optimization of mechanical properties for polycarbonate and Acrylonitrile-Butadiene-Styrene blends using Principal Component Analysis. Four controllable factors of the injection moulding process were assigned at three levels each. The Taguchi method was first employed to study the single-response optimization of mechanical properties. Principal Component Analysis was then employed to correspond to multi-response cases, for transforming the correlated mechanical properties to a set of uncorrelated components and evaluating the principal components. The optimum process factor/level combinations, based on different number of principal components, were determined. The appropriate number of principal components, and the impact of that number on the optimum process conditions, were studied by extracting more than one principal component and integrating them into a comprehensive index. Finally, the analysis of variance was used to find out the most influential injection moulding parameter for single and multiple responses problems.
The Effect of Certain Morphological Features on the Permeability of Clustered Fibrous Media
Authors: Papathanasiou T.D. , Chen X.
Published: September 2018

A good understanding of the microscopic details of flow through fiber preforms remains a critical step in the design and optimization of composite liquid molding processes such as Resin Transfer Molding (RTM) and its variants. However, the measurement of the key relevant property, namely the permeability of the preform, is still not standardized and remains difficult to perform as well as to interpret. In this paper, numerical results are presented for boundary element simulations of creeping flow through model fibrous media made up of parallel fiber bundles. Starting from ordered arrays of fiber bundles, several types of microstructural variations are introduced, and their effect on permeability is examined and quantified. It is shown that deviations from regular arrays cause substantial scatter in the corresponding permeability values. These results help to understand the large data scatter typically observed in permeability measurements.
Numerical Simulation Based Process Window for Consolidation of Thermoset Composite Laminates
Authors: Li Min , Gu Yizhuo , Li Yanxia , Zhang Zuoguang
Published: September 2018

Laminate consolidation is greatly important for continuous fibre reinforced thermoset resin matrix composites and the degree of consolidation depends on resin rheological behaviour and processing conditions. This study focused on the rheological characteristics of two kinds of epoxy resins and a bismaleimide resin and developed an evaluating method based on numerical simulation, providing guidelines to ensure consolidation. The rheological characteristics at isothermal conditions were discussed and the determination of gel point using viscosity increment rate was adopted. Autoclave process for T700S carbon fibre composite laminates was simulated numerically and the effects of cure cycle, number of plies and lay-up type of fibre bed on consolidation were analysed. A process window was constructed to achieve the required degree of consolidation by adjusting the external pressure and the time of applying external pressure. The results show that the quantitative impacts of processing conditions on consolidation and the feasibility of processing operations can be obtained from the established process window.
Structure and Properties of PVA/SiO2 Interpenetrating Polymer Network Materials Prepared by the Sol–Gel Method
Authors: Quan Feng-yu , Chen Li-Li , Xia Yan-zhi , Ji Quan
Published: September 2018

Organic–inorganic interpenetrating polymer network (IPN) materials were prepared by hydrolysis and condensation of tetraethoxysilane (TEOS) in poly(vinyl alcohol) (PVA) solution. The structure and morphology of the IPNs were investigated by infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The thermal properties were examined by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). FTIR spectroscopy showed the formation of Si–O–C and Si–O–Si bonds in the system. TEM demonstrated a homogeneous dispersion of silica in the PVA matrix when the amount of TEOS added was appropriate. DSC and TGA revealed that, compared with pure PVA films, the hybrid films exhibited a higher glass transition temperature (Tg) and high thermal stability.
Synthesis, Characterisation and Analysis of Hibiscus Sabdariffa Fibre Reinforced Polymer Matrix Based Composites
Authors: Singha A.S. , Thakur V.K.
Published: September 2018

The scope of the present paper is to study the perspectives of using natural fibres as reinforcing materials in polymers. In the present paper, the synthesis and characterisation of Hibiscus Sabdariffa fibre reinforced phenol-formaldehyde resin matrix based polymer composites have been reported. The effects of fibre loading on mechanical properties such as tensile strength, compressive strength, flexural strength, and wear resistance have also been determined. The polycondensation reaction between different molar ratios of phenol and formaldehyde has been carried out for the synthesis of phenol-formaldehyde resin polymer matrix in the presence of a base catalyst. Reinforcement of the phenol-formaldehyde (PF) resin with Hibiscus Sabdariffa fibre was done with the filler in the form of 200 micron particles. The results reveal that mechanical properties such as: tensile strength, compressive strength, flexural strength and wear resistance of the PF resin increase up to 30% fibre loading and decrease beyond this fibre loading.
Blending Techniques Affecting Mechanical and Morphological Properties of Fly Ash/Ldpe and Caco3/LDPE Composites
Authors: Chaochanchaikul Kantima , Kositchaiyong Apisit , Sombatsompop Narongrit
Published: September 2018

The effects of blending methods on mechanical and morphological properties of CaCO3/LDPE and fly ash/LDPE composites were investigated as a function of filler loadings. The CaCO3/LDPE and fly ash/LDPE composites considered in this work were prepared by dry blending (high-speed mixer) and melt blending (using single- and twin-screw extruders). It was found that as the CaCO3 or FA loading was increased, the modulus and hardness for all blending techniques were increased, due to rigidities of the fillers and increased crystallinity level of the composites. Increasing the CaCO3 and FA loadings decreased the ultimate mechanical properties (tensile strength, elongation at break and impact strength) due to poor dispersion and interfacial defects of the composites. Composites prepared by the twin-screw extruder had the best mechanical properties as compared to those prepared by the dry blending or single-screw extruder, except for the impact strength. The overall mechanical properties of LDPE composites with CaCO3 were similar to those with FA particles, but the changes in the composite properties with CaCO3 particles were more sensitive than those with FA particles, this being associated with the differences in particle characteristics and dispersion level of CaCO3 or FA fillers.
An Investigation of the Flammability, Morphology and Torque Rheology of Poly(Vinyl Chloride) with Silanes and Cu2+ Modified Montmorillonites
Authors: Li Bin , Yang Zhihua
Published: September 2018

Silane-modified montmorillonites(MMTs) and Cu2+-silane modified MMTs have been prepared by treating Na+ montmorillonites (Na+-MMTs) with silane coupling agents and copper (II) sulfate, and poly(vinyl chloride)(PVC)/modified MMT composites were prepared by using a twin-screw extruder. The microstructures of the modified MMTs and the composites were characterised by XRD and SEM. The results indicated that the silanes and Cu2+ were intercalated into the interlayers, and that the silane-modified MMTs and Cu2+-silane modified MMTs were exfoliated and dispersed in PVC by the melt-intercalation method. A small amount of Cu2+ was observed to shorten slightly the interlayer spacing of MMTs. The cone calorimetric data demonstrated that Na+-MMTs and modified MMTs changed the flammability behaviour of the composites; they effectively reduced the peak heat release rate (pk-HRR), peak smoke production rate (pk-SPR), total smoke production (TSP) and ignition time (IT). Cu2+-silane modified MMTs presented a better smoke suppressant effect than Na+-MMTs and silane modified MMTs, and the smoke-reducing efficiency of Cu2+-silane modified MMTs reached 44% although the Cu2+-silane modified MMTs contained only a small amount of copper (II) ion, 0.6~0.8%. The torque experiments indicated that silane modified MMTs improved the processability of the composites, while Cu2+-silane modified MMTs obviously increased the plasticising time of the composites. The tensile strength and flexural strength of the composites increased compared with PVC/Na+-MMTs composite.
Characterisation of Hydroxyapatite/Bacterial Cellulose Nanocomposites
Authors: Zhang Shengnan , Xiong Guangyao , He Fang , Huang Yuan , Wang Yulin , Wan Yizao
Published: September 2018

A novel nanocomposite material consisting of hydroxyapatite (HAp) deposited on a phosphorylated bacterial cellulose (BC) has been synthesised via a biomimetic route. X-ray photoelectron spectroscopy (XPS) showed that phosphate groups were successfully introduced to the hydroxyl groups of BC by phosphorylation reaction to promote the growth of calcium phosphate. Transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) patterns of HAp/BC demonstrated that HAp crystals wrap the surfaces of BC fibres. In this work, HAp/BC nanocomposites were studied using thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA result suggested that HAp/BC nanocomposite, similar to natural bone in terms of composition, contained carbonate ions, in agreement with our previous Fourier transform infrared (FTIR) spectroscopy results. Thermal behaviour differences between BC and HAp/BC were observed by differential scanning calorimetry (DSC). The thermal stability of HAp/BC obtained from DSC showed an improvement when compared to that of a pure BC sample.
Physical Properties of Polydimethylsiloxane-Containing Elastomers and Their Electrospun Nanofibre Mats
Authors: Chai W.L. , Shu Y.C. , Tseng W.C. , Chen C.C. , Jang S.C. , Chow J.D. , Chuang F.S. , Lin M.F.
Published: September 2018

A series of polydimethylsiloxane-containing elastomers (S elastomers) were synthesised from 4,4′-diphenylmethane diisocyanate (MDI), 1,4-butanediol (1,4-BD) and polydimethylsiloxane (PDMS). Through TGA analysis, S elastomers exhibited a four-stage degradation. The first and second stages resulted from the degradation of hard segment; the complicated degradation behaviour in the stages is associated with two hard-segment structures in the S elastomers. The third stage was the decomposition of PDMS, in which a cyclosiloxane degradation product was formed; subsequently, at a higher temperature it proved to be macrocyclics, which were degraded in the vicinity of 550 °C. Obviously, the degradation of S elastomers differed from the two-stage degradation of conventional polyurethane. Compared to conventional polyurethane, S elastomers presented better mechanical properties, showing the strength and elongation at break about 5.6~20.6 MPa and 550~830 %, respectively. With the better mechanical properties of S elastomers, nano-structured fibre mats were produced by electrospinning. Fibre morphology was observed by SEM and the effects of processing variables, including solution concentrations and voltages, on the morphology were evaluated.
Effects of Surface Treatment of Ground Rice Husk on the Polyurethane Based on Castor Oil
Authors: Sherif Sayed A. , Sadek M.A. , Ashour F.H. , Bassyouni M.
Published: September 2018

Polyurethane (PU) elastomer based on castor oil and polymeric diphenylmethane diisocyanate (PMDI) was synthesised with NCO/OH ratio = 2 as a polymeric matrix. Polyurethane was composited with rice husk with average particle size less than 200 μm. Ground rice husk was pretreated by steam and sodium hydroxide solution in order to study and evaluate the effect of different surface treatment methods on the properties of the polyurethane composites. Scanning Electron Microscopy (SEM) was used to investigate dispersion and fracture surfaces of the composites. Mechanical test (hardness), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC), were employed to characterise the developed composite materials in details. Composite polyurethanes based on treated and untreated rice husk showed different physical, chemical and mechanical properties. SEM micrographs of PU-treated rice husk (steam) displayed rice husk tightly embedded in the PU matrix with uniform distribution. The steam treatment increased the interfacial adhesion within the material, which showed a high thermal stability. PU-treated rice husk (sodium hydroxide 10 wt.%) showed poor mechanical properties. Untreated rice husk showed moderate mechanical properties as compared to the preceding cases.
Surface and Composite Interface of Carbon Fibre Modified by Pre-Irradiation
Authors: Xu Zhi Wei , Chen Li , Liu Liangsen , Chen Guang Wei , Wu Xiaoqing
Published: September 2018

The γ-ray pre-irradiation induced method was employed to study the effect of chloroepoxypropane modification on the surface of carbon fibre (CF) and the interfacial properties of CF/epoxy. Systematic experimental work was conducted to determine the fibre surface topography, fibre surface energy, fibre tensile strength and interfacial adhesion of CF/epoxy before and after γ-ray pre-irradiation grafting. The roughness and surface energy were all found to increase significantly. The tensile strength of carbon fibres was improved marginally by γ-ray pre-irradiation. The surface modification of carbon fibres led to an improvement (at most 18.2%) of the interlaminar shear strength of CF/epoxy composites. The mechanisms of pre-irradiation of CF are proposed.