bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Graft Copolymers of Acrylamide and Comonomers on to Cellulose: A Study of the Effect of Comonomer on Polymer Yields, Structure and Properties
Authors: Chauhan Ghanshyam S. , Guleria Lalit , Lal Harinder
Published: September 2018

Cellulose extracted from pine needles was graft copolymerized with acrylamide using benzoyl peroxide as initiator. Following a novel synthetic strategy and using the optimum reaction conditions evaluated for the grafting of acrylamide, some comonomers viz: glycidyl methacrylate, 2-hydroxyethyl methacrylate, acrylic acid and acrylonitrile have been grafted along with acrylamide using five different concentrations of the comonomers. SEM, FT-IR and thermal studies of graft copolymers were carried to obtain evidence of the incorporation of acrylamide and comonomers into cellulose. Reactivity of acrylamide in grafting reactions alone and in the presence of comonomers has been studied. The molar ratio of acrylamide and comonomers, and hence the structure of the graft chain remains independent of the comonomer concentration in the feed. It has also been observed that compared to acrylamide, less acrylonitrile was incorporated while far higher amount of the methacrylates were incorporated in the graft chain.
Effect of Testing Conditions on Performance and Durability of Stabilisers in Plastics
Authors: Pospíšil J. , Horák Z. , Pilař J. , Nešpurek S. , Billingham N. C. , Habicher W. D.
Published: September 2018

The accelerated thermal aging and weathering of stabilised plastics provides information on stabiliser efficiency and polymer durability more quickly than natural testing. This allows the monitoring of the material properties of plastics in the foreseen application environment and the development of new stabilisation formulations. The harshness of the testing method affects the individual processes involved regarding their activation energies and mechanisms, the physical relations in the polymer – stabiliser system, and the chemical and physical processes accounting for the consumption of stabilisers. The principal factors affecting any comparison of accelerated results with natural testing are outlined.
Improvement of the Properties of Polyethylene with Chlorinated Polyethylene (CPE)
Authors: Marossy Kálmán , Bárczy Pál
Published: September 2018

Blends of high density polyethylene (HDPE) and chlorinated polyethylene (CPE) have been tested across the whole concentration range. Polyethylene is used to modify the properties of CPE in the elastomer industry, but modification of the properties of polyethylene with CPE is still not usual.

Conventional mechanical tests and dynamic mechanical tests were carried out. The blends were found to be multiphase systems of excellent technological compatibility. Between 10 and 15% by weight CPE increased the modulus of polyethylene. X-ray scattering studies showed that the blends contained structural units not present either in the polyethylene or in the CPE. The blends were melt processable and may have industrial applications, too.
Morphology and Mechanical Behaviour of Poly(3-hydroxybutyrate)/Functionalized Ethylene Copolymer Blends
Authors: Dias Marcos L. , Giornes Alexey M. , Mendes Luis C.
Published: September 2018

The morphology and mechanical properties of blends prepared from poly(3-hydroxybutyrate) (P(3HB)) and ionomers formed by copolymerization of ethylene and methacrylic acid, either in the acid form (I-H) or partially neutralized with Zinc (I-Zn) and Sodium (I-Na) were investigated. Blends containing 5 to 30% of I-H, I-Zn and I-Na were prepared in an internal mixer and in a twin screw extruder. Specimens were prepared by compression and injection molding and submitted to SEM analysis and tensile and impact tests. During processing of the mixture P(3HB) with I-Na degradation of the polymer took place, with gas evolution. P(3HB)/I-H and P(3HB)/I-Zn blends presented phase separation morphologies, with the ethylene copolymer domains forming cylindrical structures. Both the Young's modulus and stress decreased and were dependent on the blend processing method and the ionomer used. The elongation at break increased by 120% as a result of the second component addition. The best impact resistance was noticed in blends containing 30% of I-Zn, with an increase of 53%. There was a strong indication that exchange reactions occurred during the mixing process. The extent of these reactions was dependent on residence time and the ionomer content of the blends.
Ink-Eliminated Paper Sludge Flour as Filler for Polypropylene
Authors: Qiao Xiuying , Zhang Yong , Zhang Yinxi
Published: September 2018

Ink-eliminated paper sludge flour (IESF) from the recycling of waste paper was used as a new kind of filler in polypropylene (PP). The crystal structures, thermal behavior and mechanical properties of the resulting composites were investigated and compared with those of conventional PP filled with calcium carbonate (CaCO3). The addition of the filler not only had positive and negative effects on the crystal growth of the α-phase and β-phase of PP respectively, but also induced the crystallization orientation of PP along the b-axis and made the PP composites possess higher crystallization and melting temperatures, due to its nucleation regent effect. Experimental results also showed that the nucleation regent effect of IESF was better than that of CaCO3 for PP crystallization. With the same filler content, the mechanical properties of the IESF/PP composites are better than those of CaCO3/PP composites, except for the impact strength and elongation.
Effect of Heat Treatment on the Tensile Strength of Glass Fibre Reinforced Polypropylene
Authors: Lin Jeng-Shyong
Published: September 2018

Improvement of the interfacial adhesion by heat treatment of glass fibre reinforced polypropylene composite was studied. Polypropylene blended with glass fibres was injection-molded. The molded parts were heat treated at various temperatures for various times. Characterization of the mechanical properties of the resulting samples was performed including measurement of the critical fibre length, and differential scanning calorimetry. The results show that the critical fibre length increases while the tensile strength decreases with increasing testing temperature. At 25 and 80°C, heat treatment can improve the tensile strength. At or above 120°C, certain treatment conditions cause the tensile strength to drop significantly.
Prediction of Permeability Tensor for Plain Woven Fabric by Using Control Volume Finite Element Method
Authors: Song Y. S. , Chung K. , Kang T. J. , Youn J. R.
Published: September 2018

The complete prediction of the second order permeability tensor for a three dimensional multi-axial preform is critical if we are to model and design the manufacturing process for composites by considering resin flow through a multi-axial fiber structure. In this study, the in-plane and transverse permeabilities for a woven fabric were predicted numerically by the coupled flow model, which combines microscopic and macroscopic flows. The microscopic and macroscopic flows were calculated by using 3-D CVFEM(control volume finite element method) for micro and macro unit cells. To avoid a checkerboard pressure field and improve the efficiency of numerical computation, a new interpolation function for velocity is proposed on the basis of analytical solutions. The permeability of a plain woven fabric was measured by means of an unidirectional flow experiment and compared with the permeability calculated numerically. Reverse and simple stacking of plain woven fabrics were taken into account and the relationship between the permeability and the structures of the preform such as the fiber volume fraction and stacking order is identified. Unlike other studies, the current study was based on a more realistic three dimensional unit cell. It was observed that in-plane flow is more dominant than transverse flow within the woven perform, and the effect of the stacking order of a multi-layered preform was negligible.
Dual-Cure Propargyl Novolac-Epoxy Resins: Synthesis and Properties
Authors: Nair C.P. Reghunadhan , Vijayan Dhanya , Gouri C.
Published: September 2018

A partially propargylated oligomeric phenolic novolac (PPN) was synthesised by the Williamson's reaction of a novolac with propargyl bromide and was characterised. Reactive blending of the PPN resin with epoxy resin resulted in a dual cure thermoset. The curing occurred through the phenol-epoxy reaction at about 135°C together with a Claisen rearrangement and the addition polymerisation of propargyl ether groups at around 235°C. The phenol-epoxy reaction could be catalysed by triphenyl phosphine, without affecting the curing of the propargyl ether groups. The cure characterisation was done by DSC and DMA. The effect of the phenol-epoxy ratio on the adhesive properties of the PPN-epoxy blend between aluminium adherends was evaluated. The system exhibited moderately good lap shear strength which was optimised for a phenol:epoxy equivalent ratio of 2:1. Good retention of the properties was observed at 100°C. On a comparative scale, the diglycidyl ether of bisphenol-A was better than the novolac epoxy, in improving the adhesion. Addition of conventional matrix tougheners was not conducive to improved adhesion. The system formed a good composite with glass fabric. The mechanical properties of the glass laminates were independent of the phenol-epoxy stoichiometry. The cured system possessed good thermal stability and a Tg>300°C. The epoxy adversely affected the Tg and the thermal stability.
Phosphazene-Triazine Polymers by Alder-ene Reaction
Authors: Nair C.P. Reghunadhan , Ninan K.N.
Published: September 2018

Cyclomatrix phosphazene-triazine polymers were synthesized by co-curing a blend of tris (2-allylphenoxy) triphenoxy cyclotriphosphazene (TAP) and tris (2-allylphenoxy) s-triazine (TAT) with bis-(4-maleimido phenyl) methane (BMM). The co-curing of the three component resin was investigated by dynamic mechanical analysis using rheometry. The cured polymers with a phosphazene-triazine ratio of one and varying BMI-content were evaluated for their physical, thermal and mechanical properties. Tensile strength tended to decrease and the modulus increased with a corresponding decrease in elongation on enhancing the maleimide-content. The tensile properties were better for a composition with an allyl/maleimide ratio of two. Dynamic mechanical analyses implied a continuous modulus decrease with rise in temperature. The temperature of onset of thermal degradation and Tg of the cured polymers increased in proportion to the maleimide–content. Phosphazene and triazine were conducive to a reduction in the rate of thermal erosion at high temperatures.
A Zone Drawing Method to Determine Optimum Initial Concentration of Poly(vinyl alcohol) to Make Films with Different Degrees of Saponification
Authors: Kim Joon Ho , Yoon Won Sik , Yeum Jeong Hyun , Ji Byung Chul , Kim Hee Sam , Jeon Han-Yong , Lyoo Won Seok
Published: September 2018

To prepare poly(vinyl alcohol) (PVA) films for various industrial and biomaterial applications, the effects of polymer concentration and degree of saponification (DS) on the draw ratio and physical properties of PVA films were investigated. Atactic PVA (a-PVA) films were prepared by casting in water with different polymer concentrations of 2.5, 5.0, 7.5, 8.5, and 9.5 g/dl, respectively. The a-PVA films were zone-drawn under various conditions. Using the optimum polymer concentration of the a-PVA/water solutions caused a significant change in the draw ratio of the films. Draw ratios of a-PVA films were maximized at the initial polymer concentrations of 7.5 and 8.5 g/dl, but gradually decreased at higher or lower concentrations. Furthermore, the birefringence, degree of crystal orientation, and tensile properties of a-PVA films having the same draw ratios were the highest at these optimum polymer concentrations. These optimum concentrations were reconfirmed by viscometry. Optimum conditions of the film casting of atactic PVAs with various DSs have been established by the zone drawing method. The agreement between the optimum concentration values obtained by zone drawing and viscometry suggests that the zone drawing method is an appropriate and convenient way to establish the optimum concentration for maximum draw ratio, birefringence, degree of crystal orientation, and tensile properties.
Fracture Toughness of Discontinuous Long Glass Fiber Reinforced Polypropylene: An Approach Based on a Numerical Prediction of Fiber Orientation in Injection Molding
Authors: Rizov V. , Harmia T. , Reinhardt A. , Friedrich K.
Published: September 2018

The fracture toughness of discontinuous long glass fiber reinforced injection-molded polypropylene has been characterized by using the microstructural efficiency concept in combination with a numerical prediction of the fiber orientation during injection molding. The latter was performed by using the SIGMASOFT commercial software. In a three-dimensional numerical scheme, input data such as fiber volume fractions, shear viscosity and mean fiber aspect ratio have been used in order to perform the mold filling analysis. The resulted local fiber orientation parameters for injection molded square plates of long glass fiber reinforced polypropylene allowed to calculate the local fracture toughness with microstructural efficiency concept. The latter were compared with the experimental toughness values obtained by the use of compact tension test specimens. The good correlation between the calculated fracture toughness data and the measured ones shows that a fiber orientation prediction by the SIGMASOFT finite element computer code can be used in combination with the microstructural efficiency concept for the determination of local fracture toughness values in injection molded long glass fiber reinforced thermoplastics. The combined approach opens good opportunities for optimization of a thermoplastic workpiece in its design with respect to local fracture resistance. This will enable the material performance levels to be significantly extended, with consequent increases in engineering applicability.
Polyacrylate/(Chitosan Modified Montmorillonite) Nanocomposite: Water Absorption and Photostability
Authors: Qiu Haixia , Yu Jiugao , Zhu Junli
Published: September 2018

Montmorillonite (MMT) was modified with chitosan (CS). The XRD and FT-IR analyses showed that the CS chains had intercalated into the MMT sheets and the strong chemical interaction between the Si-O bonds from MMT and the -NH2, -CONH- and -OH groups from CS was the driving force for intercalation. Polyacrylate (PAA)/modified MMT superabsorbent composites were fabricated by effectively dispersing the modified MMT in acrylic acid solution and polymerizing the acid. Compared with PAA, the water absorption of the PAA/modified MMT composite was increased by 91 g/g. This might arise from the combined effect of the hydrophilic groups from PAA and CS and the strong interaction between modified MMT and PAA; this explanation was consistent with the FT-IR spectrum. The introduction of unmodified MMT to PAA caused a 171 g/g water absorption loss. The rate of water absorption of PAA/modified MMT superabsorbents was decreased and the capacity for water retention was higher than that of PAA and PAA/unmodified MMT. This could be explained by the barrier properties of the nanodispersed MMT sheets in the PAA/modified MMT composites. After exposure to a high pressure mercury lamp for 20 days, PAA/PAA/MMT and PAA/modified MMT superabsorbents had losses in water absorption of 12.1%/8.6%/5.8% respectively.
Synthesis of Multiblock Copolymers of Poly(2-vinylpyridine) and Polyoxyethylene and their Application as Compatibilizers for Epichlorohydrin Rubber/Poly(Vinyl Chloride) Blends
Authors: Wang Chaoyang
Published: September 2018

Multiblock copolymers of poly(2-vinylpyridine) (P2-VP) and polyoxyethylene (PEO) were synthesized by condensing telechelic dihydroxy poly(2-vinylpyridine) (THPVP) and PEO with dichloromethane in the presence of potassium hydroxide. The copolymers were purified by extraction with water and toluene successively and characterized by Fourier Transform Infrared Spectroscopy and nuclear magnetic resonance spectroscopy. The block copolymers behave as good compatibilizers for the blending of epichlorohydrin rubber (CHR) with poly(vinyl chloride) (PVC). The addition of approximately 2-3% block copolymer to the blends evidently improves their mechanical properties and causes the two glass transition temperatures ( Tg) to become closer. The blends with a weight ratio PVC/CHR of 4/6 and the addition of 2-4% block copolymer show mechanical properties consistent with those of a thermoplastic elastomer.
Covalently Connecting Nanoparticles with Epoxy Matrix and its Effect on the Improvement of Tribological Performance of the Composites
Authors: Luo Ying , Rong Min Zhi , Zhang Ming Qiu
Published: September 2018

Graft polymerization of glycidyl methacrylate onto nano-SiC particles by means of soapless emulsion polymerization results in composite particles consisting of SiC core and polymeric shell, in which polyglycidyl methacrylate (PGMA) is bonded to the nanoparticles by the double bonds introduced during the pretreatment with a coupling agent. Compared with untreated nano-SiC particles, the grafted versions exhibit improved dispersibility. Besides, they are able to establish chemical bonding between the fillers and matrix through the reaction between the epoxide groups and the curing agent when being compounded with epoxy. As a result of these advantages, the epoxy composites filled with PGMA grafted nano-SiC particles possess rather high sliding wear resistance and low frictional coefficient at low filler loading, which cannot be observed in untreated SiC nanoparticles/epoxy system.
Fibre Orientation and Mechanical Properties of Short Glass Fibre Reinforced PP Composites
Authors: Chen Minjie , Wan Chaoying , Zhang Yong , Zhang Yinxi
Published: September 2018

The fibre orientation and distribution in short glass fibre (SGF) reinforced polypropylene (PP) composites were measured and an orientation function ( f) was introduced to describe the fibre orientation distribution. The fibre orientation distribution in the same level plane depended on the fibre position in an injection-moulded plate. The fibres close to the boundary wall of the injection cavity were parallel to the injection direction and those close to the back wall were perpendicular to the injection direction. A commercial maleic anhydride grafted PP (MAPP) was used as a compatibilizer. With the addition of MAPP, the fibre orientation distribution in PP/SGF/MAPP composites was slightly different from that of PP/SGF, but MAPP improved the interfacial adhesion between SGF and PP and consequently the mechanical properties. The use of SGF increased the tensile strength of the PP composites from 26.5 to 45.9 MPa (73% improvement), and for the PP/MAPP/SGF composite the tensile strength increased further to 55.4 MPa. The effect of SGF on the tensile strength can be expressed by a fibre efficiency factor (λσ). The SGF efficiency factor of PP/MAPP/SGF (0.198) was 45% higher than that of PP/SGF (0.137). The impact strength of PP/MAPP/SGF (64.7 MPa) was not only higher than that of PP/SGF (40.8 MPa) by 59% but also higher than that of PP (48.3 MPa) by 34%.
Modification of Sodium Salt of Partially Carboxymethylated Guar Gum by Graft Copolymerization with Methyl Acrylate
Authors: Trivedi Jignesh H. , Patel Natu K. , Trivedi Harikrishna C. , Kalia Kiran
Published: September 2018

Grafting of methyl acrylate onto sodium salt of partially carboxymethylated guar gum (backbone) was carried out using ceric ammonium nitrate as a redox initiator in an aqueous medium. The reaction variables including concentrations of initiator, nitric acid, monomer and amount of the backbone as well as time and temperature were varied for establishing the optimized reaction conditions for grafting. The influence of these reaction parameters on the grafting yields and the rates of polymerization, graft copolymerization and homopolymerization was also studied and the results were discussed. The kinetic scheme of free radical graft copolymerization was proposed and the experimental results were found to agree very well with the proposed kinetic scheme. The graft copolymer sample was characterized by IR-spectroscopic, thermal and scanning electron microscopic techniques.
Characterization Formula for Shear Stress of Polymer Melt Dynamic Extruding through Capillary
Authors: Liu Yue Jun , Xu Bai Ping , Shi Pu , Cao Xian Wu , Qu Jin Ping
Published: September 2018

The mathematical model for the shear stress in a polymer melt within a capillary was set up by superimposing a sine vibration of small amplitude in parallel with the extruding direction of the polymer melt. By making use of experimental equipment of the constant velocity type dynamic rheometer of capillary (CVDRC), designed by the authors, the steps required to calculate the shear stress in the polymer melt at the inside wall of the capillary under a vibration force field were also established. By measuring the instantaneous data of capillary entry pressure, capillary volume rate and their phase-difference under a superimposed vibration, the shear stress of the polymer melt at the wall of the capillary can be calculated.
The Effect of Solvent on the Miscibility of Blends of Poly 1-[4-(3-carboxy-4-hydroxy-phenylazo)benzene Sulphonamido -1,2-ethanediyl, sodium salt)] (PAZO) and Polyhydroxybutyrate, (PHB)
Authors: Sharma *Lakshmi , Nishida Koji , Kanaya Toshiji
Published: September 2018

The commercial world demands new photonic materials, pandering to the consumer's every whim. The target now is to produce an eco-friendly, cost-effective photonic material. This is possible by blending poly 1-[4-(3-carboxy-4-hydroxy-phenylazo)benzene sulphonamido-1,2-ethanediyl, sodium salt)], (PAZO), with polyhydroxybutyrate, (PHB).

We analysed the behaviour of PAZO/PHB blends in various solvents, dependent on the solubility parameter calculations for amorphous PHB. Differential Scanning Calorimetry was employed to determine the glass transition temperatures and to assess miscibility. This paper aims to address and establish the effect of the solvent on the miscibility of PHB/PAZO blends. We have established that a complex, is formed at high PHB concentrations, via the O-H bond of the PHB and PAZO in all solvents.
Preparation and Characteristics of Reactive Blends of Phosphate-Containing Maleimide and Epoxy Resins
Authors: Shu Wei-Jye , Chiu Hsiu-Jung
Published: September 2018

Three kinds of phosphate-containing maleimide(PMI) monomers, namely diethyl (4-(N-maleimido) phenyl) phosphate (4P) diphenyl (4-(N-maleimido) phenyl) phosphate (PP) and diethyl (2,6-dibromo-4-(N-maleimido)phenyl) phosphate (BrP), were synthesized and blended with a bisphenol type epoxy so as to study their potential as reactive flame retardants. It was expected that with an increase in the PMI content in the blending system, the Michael-addition reaction would take place more and easily. Increasing the PMI contents reduced the storage modulus, the Tg and the tensile strength, however good thermal stability was maintained. The flame retardancy of all the phosphate-containing epoxy systems was promoted significantly by increasing the PMI content.
Multiple Injection Port Simulation for Resin Injection Pultrusion
Authors: Rahatekar S.S. , Roux J.A. , Lackey E. , Vaughan J.G.
Published: September 2018

Resin injection pultrusion is a continuous process for manufacturing composite materials. Complete wet-out of the reinforcement fibres in the resin injection chamber is essential for producing good quality pultruded parts. The magnitude of the injection pressure is extremely important to achieve good wet-out of the reinforcement fibres. At high pull speeds, high viscosity, or high fibre volume fractions, the injection pressures required to achieve complete wet-out are very high and are practically very difficult to achieve. This work focuses on reducing the injection pressure needed to achieve complete wet-out by using a multiple injection port system for epoxy/glass rovings and polyester/glass rovings composites. The recommended injection pressures for complete wet-out are predicted for a variety of processing parameters. Darcy's law for flow through porous media is employed for modelling the fibre/resin system of injection pultrusion. The governing equations are solved via the finite volume method to predict the resin pressure field, the resin velocity field, and the location and shape of the resin flow front. Different permeability models1,2 are used to determine the transverse permeability and the longitudinal permeability.
Non-isothermal Cure Kinetics of Polybenzoxazine/Carbon Fiber Composites by Phase Change Theory
Authors: Xin Chunling , Yang Xiaoping , Yu Dingsheng
Published: September 2018

The cure of benzoxazines (BA-a) and benzoxazine/carbon fiber (BA-a/CF) composites was monitored by non-isothermal differential scanning calorimetry (DSC) at various heating rates. The characteristic temperatures of BA-a and BA-a/CF were analysed. The results showed that the initial cure temperature of BA-a/CF was lower than that of BA-a at the same heating rate. Various kinetic parameters and apparent activation energies for both curing systems were obtained by using a modified version of the Avrami equation. For BA-a, the apparent activation energy was 116.8 kJ/mol, which agreed well with the published data. For BA-a/CF, the results showed that the plot of Avrami rate constant vs. 1/T was not a straight line for the whole curing temperature range, but it displayed a marked change in slope at around 220 oC. The apparent activation energies at primary and second section were 105.6 kJ/mol and 224.8 kJ/mol respectively. The cure reaction of benzoxazines was not only catalysed by carbon fiber, but also was retarded by it.
Tensile and Impact Performance of Polypropylene Microcomposite System: Effect of Novel Silica Ash Filler
Authors: Chaudhary Deeptangshu S , Jollands Margaret C
Published: September 2018

Polypropylene (PP) was used to study filler-polymer interactions when rice hull ash (silica ash) is used as a microfiller. Two sizes (47 and 20 μm) of silica ash particles were studied to obtain quantitative data on the composites' mechanical performance. The smaller particle size was obtained after communizing the original size. Nucleating effects were found, suggesting that there is a moderate polymer-filler interaction during melt-processing. A comparison of the effects of increasing filler loading and increasing surface treatment indicated that at higher filler loadings, the effect of surface treatment was not dominant. Reducing the filler particle size was found to improve tensile modulus and impact strength.

Removal of silica ash impurity by burning it off resulted in a significant increase in the above mentioned properties; however, similar results were not obtained after surface treatment of the unburnt ash. The results indicate that there is a possible trade-off between using the silica ash without burning, thus saving on the cost of burning off the impurities, and using the “burnt” ash and saving on the cost of surface modification.
FT-IR Study of the Morphological Interactions in PHB/PAZO Blends and their Dependence on Solvent Variation
Authors: Sharma Lakshmi , Nishida Koji , Kanaya Toshiji
Published: September 2018

In this article, we demonstrate the vital role the solvent plays in influencing the resultant blend morphology in semi-crystalline PHB/PAZO blends. We will establish the relationship between the blend's FT-IR profiles and the morphology. We will also investigate the possible formation of a PHB/PAZO complex, previously reported.

PHB/PAZO blends were prepared in chloroform, acetone and toluene, chosen because of the similarity of their solubility parameter to that of amorphous PHB. The FT-IR spectral bands in PHB responsible for changes in morphology were observed in the 950-1350 cm−1 region. These bands denote the amorphous band at 1185 cm−1, the asymmetric C-O-C vibrations, the CH2 wag and twist at 1231 cm−1 and a crystal vibration at 1279 cm−1. A series of less prominent bands sensitive to the crystalline and amorphous regions were also observed.

We deduced that penetration of PHB's crystalline shell by the solvent does occur and is crucial to complex formation and to blend miscibility.
Yield Behaviour of Rubber-Modified Epoxy Adhesives under Multiaxial Stress Conditions: Effect of Plastic Deformability of the Matrix Phase
Authors: Imanaka Makoto , Yamashita Daisuke , Suzuki Yasuaki , Fujinami Akinori
Published: September 2018

In a previous study, the yield stress in the adhesive layer of scarf and torsional butt joints with a rubber-modified adhesive was measured, and the results agreed with those calculated by a finite element method, where Gurson's constitutive equations were applied to the adhesive layer. In this study, to investigate the effect of plastic deformability of the matrix phase on the yielding behaviour of rubber-modified epoxy adhesives, the yield behaviour was investigated by using scarf and torsional butt joints, where a reactive diluent was used to vary the plastic deformability of the matrix phase. The applicability of Gurson's model was examined in terms of the yield stresses calculated by a finite element method with a variety of the model parameters. As a result, it is confirmed that the yield stresses of the rubber-modified adhesives with different matrix phases can be approximately estimated by Gurson's model, and the model parameter's agreement with the experimental data increases with increasing the plastic deformability of the matrix phase.
The Effect of Polyethylene-Octene Elastomer on the Morphological and Mechanical Properties of Polyamide 6/Polypropylene Nanocomposites
Authors: Wahit M.U. , Hassan A. , Ishak Z.A. Mohd , Bakar A. Abu
Published: September 2018

Rubber-toughened nanocomposites (RTNC) consisting of ternary blends of polyamide 6 (PA6), polypropylene (PP) and polyethylene-octene elastomer (POE) containing 4 wt% of organophilic modified montmorillonite were produced by melt compounding followed by injection moulding. The blend composition was kept constant (PA6/PP=70/30 parts by weight) while the POE content was varied between 5 and 20 wt%. Maleated PP (PP-g-MA) was used as compatibilizer. The morphology of the RTNC was studied by scanning electron microscopy and X-ray diffraction (XRD). The mechanical properties of RTNC were studied through tensile, flexural, Izod impact and fracture toughness properties. While the tensile and flexural properties were found to decrease with the increasing concentration of POE, the toughness was significantly enhanced as compared to the neat PA6/PP blends. In general, the blends containing 10-15 wt% of POE had the best balance of stiffness, strength and toughness. The addition of 30 wt% of PP in the PA6 matrix improved the compatibility between PA6 and the rubber phase. XRD established that the organoclay was well dispersed (exfoliated) and preferentially embedded in the PA6 phase.
Pultruded Hybrid Fibre (Glass/Carbon) Reinforced Unsaturated Polyester Composites: Mechanical and Thermal Properties
Authors: Chen Chin-Hsing , Lien Kung-Chin
Published: September 2018

A feasibility study on the pultrusion of hybrid fibre (glass/carbon) reinforced unsaturated polyester composites has been conducted using a proprietary method. This was in order to obtain the best mechanical and thermal properties and the optimum price composites for pultrusion. The static mechanical properties (flexural strength, flexural modulus and notched Izod impact strength), dynamic mechanical properties (dynamic storage modulus, E' and dynamic loss tangent, tanδ) and thermal properties (weight loss by thermogravimetric analysis, TGA) of pultruded hybrid fibre reinforced unsaturated polyester composites were investigated because they are of great interest and importance in structural applications, and very sensitive to the processing conditions.

Results show that the flexural modulus increased with increasing carbon fibre content. The flexural strength and notched Izod impact strength increased with decreasing carbon fibre content. The E' increased with increasing carbon fibre content, calcium carbonate content and postcure temperatures. The peak in the loss tangent was shifted to a higher temperature when the carbon fibre content was increased. From TGA, the weight loss of the pultruded composites increased with decreasing carbon fibre content in an inert (N2 gas) atmosphere. Furthermore, they increased with increasing carbon fibre content in an air atmosphere.
Revealing the Nano and Micro Mechano-Structural Collagen Polymer Bone Relationship
Authors: Sharma L. , Sakakura S. , Pezzotti G.
Published: September 2018

With an ever-growing ageing population the strain on global medical services becomes a significant dilemma. The status of the bone is one of the major complaints by the elderly. Even today, little is known about the bone's nano and micro structural-functional relationship under applied stresses and about the function of the collagen polymer. In this article, this relationship is investigated, revealing that on microcracking open and closed pores are present. A crisscross nanostructure is essential to the bone's re-healing process. Mechanisms are proposed which are in agreement with an earlier hypothesis that could not previously be substantiated experimentally. This discovery is the key to unlocking bone weaknesses, because by understanding the bone's structural function the bone deterioration problem associated with old age can be solved.
Preparation and Characterization of Graft Copolymers of Silk Sericin and Methyl Methacrylate
Authors: Song Yan , Wei Deqing
Published: September 2018

Graft copolymers of silk sericin (SS) and methyl methacrylate (MMA) using ceric ammonium nitrate (CAN) as initiator have been synthesized under nitrogen atmosphere in aqueous media. Graft copolymers (SS-g-PMMA) were characterized by Fourier transform infrared (FTIR) spectrometry and scanning electron microscopy (SEM). The images of SEM showed that the surface morphology of grafted SS was much rougher than that of ungrafted SS due to the incorporation of PMMA fragments. The analytical results of the orthogonal experimental design showed that the strongest effect on grafting efficiency was the concentration of monomer (CMMA) and the weakest was the reaction time (t). This led to further study of the effects of different factors on graft copolymerization. Finally, we proposed a possible reaction mechanism for the graft copolymerization.
Chitosan-g-Poly(Acrylic Acid)/Kaolin Superabsorbent Composite: Synthesis and Characterization
Authors: Pourjavadi A. , Mahdavinia G.R.
Published: September 2018

A novel superabsorbent composite based on chitosan was prepared by graft copolymerization of acrylic acid (AA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The synthetic variables (i.e. AA, MBA, and APS concentration, and the kaolin amount) affecting the water absorbency of the resulting superabsorbent composite were studied. Evidence of grafting and kaolin interaction was obtained by comparing the FTIR spectra of the initial substrates with that of the superabsorbent composite. A new absorption band at 1722 cm−1 in the composite spectrum confirmed the kaolin-organic polymer linkage. The effect of kaolin amount showed that increasing this parameter caused the water absorbency of the superabsorbent composite to decrease. The effect of pH on the water absorbency of the superabsorbent was also studied.
Electrical Properties and Crystallisation Behaviour of Polypropylene/Carbon Black Composites
Authors: Li Ying , Wang Shifeng , Zhang Yong , Zhang Yinxi
Published: September 2018

Four different kinds of carbon black (CB) filled polypropylene (PP) composites were prepared by the melt-mixing method. The electrical properties of the PP/CB composites were studied. All PP/CB composites showed typical characteristics of percolation but noticeably different percolation thresholds. CB with higher structure, smaller particle diameter, and larger surface area resulted in the filled PP composites exhibiting better electrical conductivity and a lower percolation threshold. In particular, the percolation threshold of the PP/CB composite filled with hollow-structured CB was significantly lower than that of the others. The crystallisation behaviour of PP/CB composites filled with various amounts of V-XC72 CB was studied by differential scanning calorimetry. The non-isothermal crystallisation parameters showed that the CB particles could act as nucleating agents, accelerating the crystallisation of PP. The isothermal crystallisation kinetics studies showed the crystallisation kinetic constant K(T) and the rate of crystallisation of the PP/ CB composites were higher than those of PP. The values of the Avrami exponent n (ca. 3) indicated three-dimensional spherutitic growth in a spherical form. The free energy of chain folding for PP crystallisation of the PP/CB composites was lower than that of PP itself and it decreased further with increasing CB content.
Coated Nano-Sized CaCO3 Reinforced Semi-Crystalline EPDM
Authors: Zhou Yabin , Wang Shifeng , Zhang Yong , Zhang Yinxi
Published: September 2018

Nano-sized calcium carbonate (CaCO3) was used to reinforce a semi-crystalline ethylene-propylene-diene monomer rubber (EPDM). For comparison, micron-sized CaCO3 was also studied. It was found that both nano-sized CaCO3 and micron-sized CaCO3 improved the mechanical properties of the EPDM vulcanizates, and nano-sized CaCO3 exhibited better reinforcement effect than micron-sized CaCO3. The difference in reinforcement effects of nano-sized CaCO3 and micron-sized CaCO3 was explained in terms of the filler particle size and the crosslink density of the vulcanizates. The nano-sized CaCO3 was also modified by titanate, borate, and aluminate-titanate complex coupling agents and used to reinforce EPDM vulcanizates. The results showed that titanate coupling agent coated nano-sized CaCO3 exhibited the best reinforcement ability. FE-SEM micrographs showed that stearic acid, titanate, and aluminate-titanate complex coupling agents could improve the dispersion of the CaCO3 in the rubber matrix remarkably, whereas borate coupling agent could not.

The effect of modified nano-sized CaCO3 on the dynamical mechanical properties was also studied. Incorporation of CaCO3 reduced the glass transition temperature (Tg) of the vulcanizates. In comparison with nano-sized CaCO3, micron-sized CaCO3 depressed the Tg more remarkably.
Increasing the Interfacial Adhesion in Poly(methyl methacrylate)/Carbon Fibre Composites by Laser Surface Treatment
Authors: Nematollahzadeh A. , Mousavi S.S.A. , Tilaki R.M. , Frounchi M.
Published: September 2018

The impact strength of poly(methyl methacrylate)/carbon (long) fibre composites for denture prosthesis applications was improved by fibre surface treatment. The carbon fibre surfaces were modified by Nd:YAG laser irradiation at 1064 nm wavelength. Laser light intensity was adjusted at 100 mJ per pulse that only changed the fibre surface roughness and did not lead to fibre rupture, as verified by scanning electron microscopy. Increased surface roughness of the fibres improved the adhesion of poly(methyl methacrylate) to the fibre surface. Adhesion between the fibres and poly(methyl methacrylate) was evaluated by a tear-off method and by scanning electron microscopy. The results also suggest that laser irradiation enhances the wettability of the fibres by introducing active sites onto the fibre surfaces which react with the resin and impart stronger interfacial adhesion.
Preparation and Characterization of Novel Organic Montmorillonite-Reinforced Blocked Polyurethane Nanocomposites
Authors: Jincheng Wang , Yuehui Chen , Yanqing Wang
Published: September 2018

This paper presents a proprietary process developed to manufacture organic montmorillonite (OMMT)- reinforced and isocyanate (-NCO) -blocked pouring-type polyurethane (BPPU) nanocomposites. The BPPU polymer was prepared from phenol- blocked blends of toluene diisocyanate (TDI), polyethylene glycol and 3,3'-dichloro-4,4'-diamido diphenyl methane (MOCA). The physical and mechanical properties of OMMT reinforced BPPU composites have been studied. BPPU samples containing 4 phr OMMT exhibited excellent mechanical properties because of the exfoliation and intercalation of the organic silicate layers.
Essential Work of Fracture (EWF) of Multilayer Films
Authors: Poisson C. , Fournier J.E. , Lacrampe M.F. , Krawczak P.
Published: September 2018

The potential of a fracture mechanics approach (Essential Work of Fracture or EWF method) to determine the toughness of PE/PEgMAH/PA multilayer films has been investigated. The films had been modified either by blending EVA in the PE and PEgMAH layers or by inserting clay nanoparticles in the PA layer. The method was first calibrated on PE and PA single layer films.

An analysis of the sensitivity of the toughness, assessed by the EWF method, to both sample geometry and test conditions has been carried out, so as to optimise the testing procedure for these materials. Then these optimal test conditions have been used to characterise PE- and PA-based multilayer films. The results show that the Essential Work of Fracture method is relevant for this type of structure, and may be more sensitive to the film composition variations than standard tensile mechanical tests, especially when the composition modification affects the layer of lowest rigidity and tensile strength.
The Durability of Glass Fibre-Reinforced Polymer Dowel after Accelerated Environmental Exposure
Authors: Won Jong Pil , Cho Yong Chin , Jang Chang Il
Published: September 2018

The corrosion of steel dowel causes potential problems in jointed concrete pavement that necessitate alternative dowel materials. Glass fibre-reinforced polymer (GFRP) dowel is a possible maintenance-free alternative that will potentially reduce the overall lifetime cost of pavement. This study evaluated the long-term durability of GFRP dowel. It was subjected to accelerated ageing at an elevated temperature under five environmental conditions: alkaline, water, salt, calcium chloride and repeated freeze-thaw cycles. The durability was quantified using the apparent horizontal shear strength test. The results of the accelerated ageing test were compared with those of the natural environment. Based on the test results, the durability of GFRP dowel is acceptable and it is very resistant to the detrimental affects of accelerated ageing.
Composite of Aramid Fibre-Thermoplastic Natural Rubber: Effect of Processing Parameters and Compatibiliser
Authors: Wong P.Y. , Ahmad Ishak , Abdullah Ibrahim
Published: September 2018

Composites have been prepared by melt blending thermoplastic natural rubber (TPNR) with aramid fibres in an internal mixer for various mixing times, at various temperatures and rotor speeds. The optimum processing parameters were 12 minutes, 155 °C and 50 rpm. The compatibilising effects of polyethylene-graft-maleic anhydride (PE-g-MA) on the composites were examined at concentrations from 0–14%. The tensile strength increased from 12.6 MPa to 15.7 MPa and modulus from 113 MPa to 136 MPa in the presence of 12% PE-g-MA. The impact strength also increased considerably. The compatibiliser also caused the storage modulus, E' to increase but a reduction in the tan delta peak. Scanning electron microscopy of the fractured surfaces revealed that strong interfaces were formed on addition of the compatibiliser.
A Conductive Hydrogel by Poly(Sodium Acrylate)/Montmorillonite Superabsorbent Composite
Authors: Xie Yiming , Wu Jihuai , Lin Jianming , Wei Yuelin , Zhong Jinfeng
Published: September 2018

Poly(sodium acrylate)/montmorillonite superabsorbent composite was synthesised by an inverse suspension polymerisation method. A novel hydrogel electrolyte with conductivity of 100 mS·cm−1 was prepared by immersing the superabsorbent composite in 1 M KCl aqueous solution. The conductivity of the hydrogel electrolyte was investigated, and it was found that the hydrogel electrolyte exhibits liquid-like ionic conductivity. The conductivity depends mainly on the ionic intensity of the solution in which it is immersed and on the water absorbency of the superabsorbent.
Effects of Coating Structures on Interfacial Properties of Carbon Fibre/Polyarylacetylene Composites
Authors: Zhang X.Z. , Huang Y.D. , Wang T.Y. , Hu L.J.
Published: September 2018

Carbon fibres (CF) were modified with different coatings, including vinyltrimethoxysilane (VMS) and vinyl-silsesquioxane (VMS-SSO). VMS-SSO was obtained by the sol-gel hydrolytic condensation of VMS. The structure of VMS-SSO was characterised by FT-IR, NMR (1H, 13C and 29Si) and UV-MALDI-TOF MS. The VMS-SSO included several structures such as cage, semi-cage and ladder. Interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) were measured to evaluate the effects of the coating structure on the interfacial properties of carbon fibre/polyarylacetylene (CF/PAA) composites.

The ILSS and IFSS of CF/PAA composites treated with VMS and VMS-SSO coatings showed that VMS-SSO coating had a better treatment effect than VMS. The fracture surface of the CF/PAA composites treated with different coatings was observed by SEM. The complex structures of the VMS-SSO seem to be the main reason for the different degrees of improvement in the interfacial adhesion.
Particleboard from Cashew Nut Shell Liquid
Authors: Mary Lubi C. , Thachil Eby Thomas
Published: September 2018

Cashew nut shell liquid (CNSL) is a cheap agro-by-product and renewable resource which consists mainly of substituted phenols. A CNSL based resol resin was used in this study as a binder for particleboards. The resin was a copolymer obtained by condensing a mixture of phenol and CNSL with hexamethylenetetramine. Properties of the board viz. water absorption, tensile strength parallel to the surface, tensile strength perpendicular to the surface and compressibility were determined. The effects of the resin content, P:F ratio and CNSL: P ratio of resin binder on the properties of particleboard were also studied. About 10% resin in the moulding formulation was essential to give a board of acceptable quality. The P:F ratio was not very significant in determining the properties. It was possible to include up to 50% CNSL without any deterioration in the properties of the board. This is significant from the conservation viewpoint.
Chemical, Structural and Thermal Changes in PET Caused by Solvent Induced Polymer Crystallisation
Authors: Rajendran S. , Mishra S.P.
Published: September 2018

The structural and thermal properties of solvent-induced poly(ethylene terephthalate) (PET) polyester have been investigated. Flat, high twist and spun yarns were treated with trichloroacetic acid-methylene chloride (TCAMC) mixed solvent for 5 min at about 25 °C. The treatment influenced the solvent- induced crystallisation in PET, and the high interacting power of TCAMC with PET was substantiated. An increase in X-ray crystallinity was observed in the treated flat yarn but the orientation was reduced. The variation in crystallinity was measured by X-ray and DSC techniques and is discussed. The melting and recrystallisation behaviour of the crystallites were indicated by DSC measurements.

The treatment improved the crystallite stability and perfection. Flat yarn exhibited a distribution of the more stable crystals with higher heat of fusion than the respective spun and high twist yarns.

The study shows that the crystalline structure reorganises to a more stable and uniform form as a result of the treatment. Double melting peaks were seen in the DSC of the high twist treated samples.