bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Delamination Buckling and Growth Behavior in Laminated Composites with Coexisting Delaminations
Authors: Yang Fan , Xu Zhonghai , Zhanga Lu , Jiao Weicheng , Liu Wenbo , Sui Xiaodong , Zhanga Jianguang , Wang Rongguo
Published: September 2018

Finite element method (FEM) using cohesive element is developed to predict delamination buckling and growth behavior in laminated composites with coexisting delaminations under compressive loading. It is shown that the buckling behavior of coexisting delaminations is far more complicated than single embedded delamination. In the course of delamination buckling and growth, a parametric study was carried out to investigate the influence of the distance between coexisting delaminations, delamination size and depth position of a series of composite plates. In particular, a three zone rule was put forwarded to define the interaction behavior between coexisting delaminations. Moreover, it is shown that the potential of delamination growth strongly depends on the distance between coexisting delaminations.
Research on Numerical Simulation of Heating Process Optimization of Heated-Mandrel Winding Method
Authors: Jiazhong Xu , Rongguo Wang , Ming Qiao , Ying Yu
Published: September 2018

The heated-mandrel winding method (HMWM) is a new technology. However, the trial-and-error method usually used is not universally adopted in the manufacturing process of shells that have different shapes and performance requirements. Determining the heating process for the HMWM based on theoretical analysis has become an immediate problem. In this paper, a numerical simulation program for the HMWM is developed using the finite element software ANSYS and the programming language APDL. The entire process, which starts with the winding process and ends with the complete curing, is numerically simulated. The temperature distribution and change law, curing degree, and reactive calorific intensity are analyzed. The relationship between the heating process and the outer surface temperature changes of the composite shell is derived based on the principle of temperature control in the HMWM. The heating process is optimized in accordance with the analysis, and the experimental results show that, based on the optimized heating process, the outer surface temperature range of the shell can be controlled during the winding process. Furthermore, the complex interactions among the temperature, curing degree, film coefficient, and heat transfer coefficient of the composite are investigated. This provides the basis for the technology optimization based on theoretical considerations.
Preparation and Properties of Mdi-Based Polyester Polyurethane Elastomer
Authors: Yuan Feng , Liu Wenbo , Yang Fan , Zhu Zhenqiang , Hao Lifeng , Zhang Jian , Jiao Weicheng , Wang Rongguo
Published: September 2018

Polyurethane has been usually used as protective coating on structures, with an important mechanism being the impact-induced transition of the rubber to the glassy state. The better the mechanical property, the greater the mechanical loss, the wider the Tg range, and the Tg is more close to, but less than, the operating temperature, the better the protective coating. Here, the pre-polymer method is adopted to synthesize MDI-based polyester polyurethane (TPU) which has different hard segment contents. The influence of the hard segment content on the relevant performance of TPU is investigated. With the increase of the hard segment content, the tensile strength, Tg of the soft segment phase and the mechanical loss increase, while the viscosity of reaction solution increases rapidly, the elongation at break declines sharply, and the range of the Tg becomes narrower and narrower. Therefore, in order to obtain excellent protective coating, the hard segment content should not be too high. Testing proves 16.18% hard segment content to be most effective.
Structure-Property Relationships in Arapaima Gigas Scales Revealed by Nanoindentation Tests
Authors: Torres F.G. , Le Bourhis E. , Troncoso O.P. , Llamoza J.
Published: September 2018

Fish scales from Arapaima Gigas have been studied in terms of their structure (morphology, collagen content) and mechanical properties. A strong mechanical gradient was revealed in the scale, hardness and reduced modulus being reduced by a factor of three. Correlations between the hardness and reduced modulus and the mineral content have been found. The external mineral rich layers were determined to be hard and stiff while the inner surface, being collagen rich, was less hard and less stiff. The inside of the scales showed a progressive decrease of mechanical properties, with variations attributed to the plywood-like structure of the scale.
Water Absorption Behaviour and Mechanical Properties of High Density Polyethylene/ Pistachio Shell Flour Nanocomposites in Presence of Two Different Uv Stabilizers
Authors: Najafabadi M.A. Abedini , Khorasani S. Nouri , Esfahani J. Moftakharian
Published: September 2018

In this research, for the first time, the effects were investigated of nanoclay as a secondary reinforcement, titanium dioxide (TiO2) and hindered amine light stabilizer (HALS) as UV stabilizers on some properties of high density polyethylene (HDPE)/pistachio shell flour (PSF) composite as the new wood plastic composite (WPC). WPCs of HDPE/PSF with different levels of nanoclay (Cloisite 20A), TiO2 and HALS were prepared. Some properties were investigated before exposure to weathering conditions. Design of experiments (DOE) was carried out to find the best formulation and decrease the number of tests. WPC granules were prepared by melt-mixing method using a twin screw extruder, and then moulded using an injection moulding machine to prepare samples. The results of X-ray diffractometry (XRD) indicated partial exfoliation and intercalation of samples containing 3 and 6 per hundred composite (phc) of nanoclay. The tensile strength and modulus of HDPE/PSF samples containing 3 and 6 phc nanoclay showed 20% increase compared to samples without nanoclay. The presence of TiO2 and HALS in the formulation did not have a significant effect on tensile properties. The nanoclay presence in HDPE/ PSF formulation improved the water absorption resistance.
Design and Analysis of Small-Scale Lift-Type Vertical-Axis Wind Turbine Using Composite Blade
Authors: Zhong-Jia Yang , Yi-Zhuo Gu , Min Li , Yan-Xia Li , Jie Lu , Zuo-Guang Zhang
Published: September 2018

This paper focuses on verifying the feasibility of applying fibre reinforced polymer matrix composite to vertical axis wind turbine. A small-scale lift-type vertical axis wind turbine using glass fibre reinforced epoxy matrix sandwich composite blade was proposed. An airfoil profile of blade was designed and a composite blade was fabricated. The structure parameters of the blade were optimized by means of the finite element modeling method. The mechanical and the resonant properties of the blade were investigated. Finally, a wind turbine with the designed blade was assembled, and its generating capacity was tested. It was demonstrated that the designed composite blade and the wind turbine had excellent performance, indicating a promising technology for utilizing wind power.
Effect of Thermal History on β-Nucleated Polypropylene Homopolymer
Authors: Wahab M.A. , Samsudin M.S.F. , Ahamid Z. , Leong K.H.
Published: September 2018

β-nucleant is used in polypropylene homopolymer (h-PP) primarily to improve its toughness as this particular property is important for piping and pipe coating application. In this work, the effect of β-nucleating agent on h-PP as topcoat material for pipe coating was investigated. The distribution of the nucleating agent in h-PP was controlled by solid-phase reactive extrusion. It was found that when subjected to second cycle of thermal exposure, the effect of β-nucleant upon h-PP crystallinity had increased significantly. This was desirable as it would enhance topcoat toughness. Several heating cycles were used to mimic the number of thermal exposures during processing. The effect of this simulated thermal history on the toughness enhancement was assessed and reported. The work has shown that, after a number of consistent thermal cycles, the percentage of β-crystals phase remained level. This will provide a much needed assurance on thermal and mechanical consistency in β-nucleated h-PP as well as enhance its viability for pipe coating applications.
Synthesis of Montmorillonite/Acrylic Acid/Acrylamide Tricopolymer and Its Super Absorbent Properties
Authors: Zhan Xiao-yuan , Wang Fang , Li Xing-wei , Wang Min
Published: September 2018

Montmorillonite/acrylic acid/acrylamide tricopolymer was synthesized by using aqueous solution polymerization. Some factors affecting the water absorbency of super absorbent composite material, such as the neutralization of acrylic acid, the amount of added montmorillonite, initiator and crosslinking agent were investigated. The best formula for absorbing the running water was proposed, it included 40% montmorillonite, 80% monomer neutralization degree, 0.08% crosslinker amount, and 0.15% initiator, and the water absorbency of the obtained composite materials was 150 times. The FTIR research indicated that montmorillonite was effectively compounded with polymer, it is found that the composite with a good water retention and heat resistance is significant for reducing the product cost and improving the comprehensive property of the composite.
Impact of Single and Multiple Injection Slot Locations for Attached-Die and Detached-Die Tapered Resin Injection Pultrusion
Authors: Ranjit S. , Roux J.A. , Jeswani A.L.
Published: September 2018

This study compares the performances of the detached-die with the attached-die resin injection chamber configurations for pultrusion manufacturing. The impact of geometric design parameters (axial location of single injection slot and axial location of multiple injection slots) on the performances and complete reinforcement wetout for both the attached-die and detached-die configurations are investigated for various chamber lengths and compression ratios. Feasible manufacturing solutions are determined from the results.
Effect of Silane Coupling Agent on Physical Properties of Polypropylene Membrane Reinforced by Native Superfine down Powder
Authors: Yang Hongjun , Dong Xia , Wang Dujin , Xu Weilin
Published: September 2018

In order to improve the compatibility between native superfine down powder (NSDP) and polypropylene (PP), NSPD was surface-modified by grafting with a silane coupling agent. After modification of NSDP, Fourier-Transform infrared spectrometry was used to investigate the chemical reaction between NSDP and silane coupling agent, and the spectroscopy indicated that silane coupling agent was successfully grafted onto the particle surface. Modified and unmodified NSDP was used to reinforce PP membrane by hot-press method, and the morphology, thermal properties, melt mass-flow rate and mechanical properties of PP/NSDP hybrid membrane was investigated. The melt mass-flow rate, tensile stress, and break elongation of the hybrid membranes initially increased and then decreased with the increase of silane coupling agent concentration, which significantly correlated with the silane coupling agent amount that adhered on the particle surface. Up to 3% silane coupling agent concentration was sufficient to cover the NSDP surface and improve the compatibility between PP and NSDP. With continuously increasing of silane coupling agent concentration, the melt mass-flow rate and mechanical properties decreased, which ascribed to the decreasing bonding strength of entanglement network between long-chain hydrocarbon segments on NSDP surface and PP matrix. PP/NSDP hybrid membrane with excellent thermal and mechanical properties can be obtained by controlling the silane coupling agent concentration.
Electrical and Steady Shear Rheological Behaviour of Polypropylene Composites Reinforced with Single-Walled Carbon Nanotubes
Authors: Narimani Amir , Hemmati Mahmood
Published: September 2018

The steady shear rheological behaviour, morphological, electrical, physical and mechanical properties of melt-blended polypropylene (PP)/single walled carbon nanotube (SWNT) were investigated. The rheological behaviour results indicated that both PP and its nanocomposites exhibited non-Newtonian behaviour. Addition of SWNT increased the shear stress and shear viscosity. It was also found that the materials experience a fluid-solid transition at 0.5 wt.% SWNT. The die swell behaviour increased with increasing shear rate and also decreased with the SWNT content. The morphology and degree of dispersion SWNT in the polypropylene matrix were investigated by SEM. The electrical percolation threshold was formed at about 1 wt.% of SWNT. In addition, a difference between electrical and rheological percolation thresholds was observed. DSC results confirmed the expected nucleate effect of SWNT on the crystallization process of polypropylene. It was also found that the tensile strength improved when 0.5 wt.% SWNT used. Furthermore, an increase in the tensile modulus was observed with increasing SWNT contents, but the elongation at break decreased.
Synthesis and Investigation of Silatrane Complex as a New Flame Retardant in Poly(Ethylene Terephthalate)/Montmorillonite Nanocomposites
Authors: Sonsilchai Phawittra , Aht-Ong Duangdao
Published: September 2018

The purpose of this research was to improve the flame retardant properties of PET using silatrane complex synthesized from silica through one pot process. In addition, the synergistic effect of flame retardant agents between silatrane complex and montmorillonite (MMT) at various concentrations was investigated. The characteristics of the obtained silatrane complex were studied by FT-IR, 29Si-NMR, SEM, and TGA. Different ratios of PET/MMT/silatrane complex nanocomposites were prepared by melt bending process using a twin screw extruder and compressed into various shapes by a compression molding machine, respectively. The effects of single flame retardant and co-flame retardant agents on morphology, flame retardant properties, and mechanical properties of PET nanocomposites were evaluated. LOI values and UL-94V rating were used as parameters for determine flame retardant properties of PET nanocomposites. The results showed that LOI values of PET/MMT/silatrane complex nanocomposites were evidently greater than that of neat PET and increased with increasing the silatrane complex concentration. The LOI value of PET/2%MMT/7%silatrane nanocomposites was highest and increased up to 60.75%, compared with that of neat PET. While neat PET was classified into V-2 rating since it showed sustainable burning and melt-dripping behavior during burning process, PET/MMT/silatrane complex nanocomposites did not show such behavior and thus could be designated as V-0 rating. The enhancing of flame retardant properties for PET nanocomposites was attributed from the synergistic effect of MMT and silatrane complex. When they undergo decomposition through an endothermic reaction, MMT and silatrane complex can form homogeneous carbonaceous char and highly silicate-crosslink structure, respectively, in the condensed phase while burning. This multilayer can significantly improve the flame retardant properties of PET/MMT/silatrane complex nanocomposites. The mechanical properties of PET/2%wt MMT nanocomposites were better than those of neat PET but further increasing the amount of MMT and silatrane complex, phase separation and agglomeration occurred leading to the reduction in the mechanical properties.
Impact of Dmdheu Resin Treatment on the Mechanical Properties of Poplar
Authors: Jiang Tao , Gao Hua , Sun Jianping , Xie Yanjun , Li Xiurong
Published: September 2018

To increase the utilization and the value of poplar, various concentrations of dimethylol dihydroxy ethylene urea (DMDHEU) were used to impregnate poplar, an important tree specie from the north of China. The resin was fixed on the timber under certain conditions, after which the weight percent gain (WPG), flexural modulus (MOR), modulus of elasticity (MOE), impact strength, hardness and compressive strength of the poplar impregnated were tested and evaluated. The results showed that WPG of poplar is positively associated with the concentrations of DMDHEU after the resin treatment; when the WPG of poplar was 62.1% and the concentration of resin was 30%, the concentration of resin shows positive correlation with MOE, the hardness of each section, the compression strength perpendicular to grain, and the compressive strength parallel to the grain, but demonstrates negative correlation with MOR and impact strength.
Research on Pretreatment Technology for Corn Husk Degumming
Authors: Zhou Rong , Yang Mingxia , Zhang Haixia
Published: September 2018

In this study, chemical degumming was applied to corn husks, and the optimal degumming procedure and pretreatment method were determined. Through orthogonal experiments, it was determined the optimal pretreatment parameters are: H2O2 concentration of 8 g/L, urea concentration of 8 g/L, pretreatment temperature of 20 °C and pretreatment time of 30 min. The effectiveness of this combination of parameters was validated by its resultant glial removal rate of 85.32%.
Photo-Anodic Polymerization of Pyrrole on Nanoclustered Tio2 from Hydrothermal One-Step on Pure Ti
Authors: Zhou Fu-fang , Li Delong , Li Weiping , Zhu Xilou , Wang Ping , Huang Yuan Ming , Pan Chunxu
Published: September 2018

Nanoclustered TiO2 networks were synthesized hydrothermally one-step in 0.45 M tetramethylammonium hydroxide (TMAOH) aqueous solution directly on pure polished Ti substrate for 12-hour growth. Polypyrrole (PPy) nanofilm was subsequently electropolymerized with galvanostatic photo-anodization on the nanostructured TiO2 sheet as the working electrode. Tafel polarization curve was employed to determine galvanostatic condition. Investigations of SEM, cyclic voltametry, potential-time growing curves, photo-response currents, UV-vis spectroscopy and Fourier Transform Infra-red (FTIR) spectroscopy revealed that photo-anodic polymerized pyrrole film could thoroughly change properties of nanoclustered TiO2 electrode. The networks of nanoclustered TiO2 was covered with homogeneous PPy nanofilm, the cyclic voltammetry revealed two reduction peaks, suggesting a compact and a porous layer of PPy. Moreover, PPy could enhance the photo-response by over 100 times compared with that of bare TiO2 nanonetworks. Optical absorbance visualized the full spectral absorptive feature of PPy, and FTIR further confirmed the vibrations of chemical bonds from PPy. This demonstrated that PPy infiltration in TiO2 nanonetworks could be successfully achieved via photo-anodic polymerization, and TiO2 nanonetworks/photo-anodic polymerized PPy are promising in applications of polymer-inorganic solar cell.
Effect of Weathering on the Properties of Wood-Polypropylene Composites Containing Minerals
Authors: Butylina Svetlana , Kärki Timo
Published: September 2018

The effect of UV-exposure on the properties of wood-polypropylene composites containing mineral fillers weathered in natural and accelerated conditions was studied. The changes in the colour of the composites after weathering were evaluated by spectrophotometry, and the changes of Charpy impact strength were measured with an impact tester. The outdoor weathering compared to accelerated weathering resulted in a greater colour change of the reference composite and composites containing calcium carbonate and wollastonite. The talc-containing composite, having low susceptibility to moisture, showed a greater colour change in the accelerated weathering test. The accelerated weathering resulted in severe degradation of the polymeric surface layer of the composites. The impact strength of a weathered composite depends on the type of weathering and the properties of the filler.
Polypropylene Fibre Reinforced Polymer Concrete: Effect of Gamma Irradiation
Authors: Martínez-Barrera Gonzalo , Martínez-Hernández Ana Laura , Velasco-Santos Carlos , Martínez-López Miguel , Ortiz-Espinoza Jesús , Reis João Marciano Laredo dos
Published: September 2018

Design of polymer concrete involves extensive studies on their materials in order to get improved properties; specifically on the physicochemical properties of both polymer resin and mineral aggregates, including size and shape of the last one. Alternative studies are focusing on using different materials or methods to obtain such improvements. In this work, polymer concrete was elaborated with unsaturated polyester resin, marble particles and polypropylene fibres, after it was modified by using gamma radiation to achieve a complete polymerization. The results show improvements in the compressive strength and in the modulus of elasticity with 0.2 vol.% of polypropylene fibres and irradiation at a dose of 250 KGy. However, lower compressive strains were obtained when using gamma radiation.
Effects of Preheating Temperature of the Mould on the Properties of Rapid-Curing Carbon Fibre Composites Fabricated by Vacuum-Assisted Resin Infusion Moulding
Authors: Zhang Kaomin , Gu Yizhuo , Wang Shaokai , Li Mi , Zhang Zuoguang
Published: September 2018

Shortening the curing time is critical to improve the processing efficiency of composites. In this paper, unidirectional carbon fibre-reinforced rapid curing epoxy composite laminates were fabricated by vacuum-assisted resin injection moulding (VARIM). Different rapid curing processes (namely P80, P85, and P90) were employed, which preheating temperatures were 80, 85 and 90 °C, respectively. Different preheating temperatures of mould and fibre preform were conducted, to demonstrate the effects on the properties and processing time of the composites. In addition, a slow curing process (N80) was investigated to verify the effect of rapid curing on the mechanical properties of the composites. The relationships among preheating temperature, curing cycle and properties of the composites were analyzed. The results showed that the preheating temperature had obvious effects on the total cycle time and properties of the composites. The cycle time of the P80 process was 947 s, whereas that of the P90 process was 702 s. However, nonuniformity of the mechanical properties along the resin flow direction was more obvious for the P90 process, and more voids formed in the resin outlet region. Composites fabricated by the P80 process showed comparable mechanical properties and processing quality to those from the N80 process. It is suggested that a rapid curing process with proper preheating temperature is acceptable to improve the processing efficiency.
Manufacturing of Transparent Composites Using Vacuum Infusion Process
Authors: Menta V.G.K. , Vuppalapati R.R. , Chandrashekhara K. , Schuman T.
Published: September 2018

A novel optically-transparent glass fibre reinforced polymer matrix composite has been developed by infusing a clear epoxy resin system of matching refractive index into a conventional E-glass fabric preform. Transparent composites are manufactured using a low cost, environmentally friendly vacuum infusion process. Physical and mechanical tests have been conducted. Transparent composites manufactured using the modified vacuum infusion process had a fibre volume fraction of 40%. Tensile strength and tensile modulus of these composites were 374.9 MPa and 31.74 GPa respectively. The results indicate that the transparent composites possess good physical and mechanical properties. These transparent composites form a good base for developing new generation transparent armour systems.
Mechanical Constitutive Relation Model of Expanded Polyvinyl Alcohol
Authors: Wang Dongmei , Zhu Hong
Published: September 2018

The compression stress-strain response of expanded polyvinyl alcohol under different influence factors had been studied by static compression experiments. The constitutive relation model of expanded polyvinyl alcohol was established based on the Sherwood-Frost model, including density, temperature, strain rate and strain, and the factor of relative humidity was added to improve the model. Finally, the accuracy of the constitutive relation model was validated by comparing calculated curves according to the constitutive relation model and experimental data; the results were in good agreement. The model can easily predict compressive stress of expanded polyvinyl alcohol under various environmental conditions, and is also meaningful to offer reference data for product packaging.
The Orientational Order of the α-Helical Backbone of Poly(γ-Benzyl L-Glutamate) – a Molecular Dynamics Simulation
Authors: Zhou Zhiping , Tao Lu , Yang Wenming
Published: September 2018

For a Poly(γ-benzyl L-glutamate) (PBLG) segment with 30 monomers, molecular dynamics simulation was carry out in the Amber forcefield, by the software package InsightII/Discover. The geometrical structure of the backbone of the model molecule in the minimized energy state is in close agreement with that in the solid polypeptides. In the dynamic equilibrium state, the structure becomes slightly flabby and has a potential ca. 4800kJ/mol higher than that in the minimized energy state for the model molecule. On the average, the α-helical backbone architecture of PBLG remains quite stable during the molecular dynamic process, though the fluctuation of the bond and dihedral angles. The observed D NMR spectra for the quadrupolar splittings are reproduced and the previous architecture analysis was verified by the simulation calculations.
Cocrystallization Behavior of Hdpe/Uhmwpe Blends Prepared by Two-Step Processing Way
Authors: Zuo Jiandong , Liu Shumei , Zhao Jianqing
Published: September 2018

Blends of high density polyethylene (HDPE) and ultra high molecular weight polyethylene (UHMWPE) were prepared by two-step processing way. Middle molecular weight polyethylene (MMWPE) as the lubricant was added into UHMWPE in the first processing step. Cocrystallization behavior of the blends was examined by DSC, XRD and light microscope (LM). A single endotherm peak in DSC curves revealed that cocrystallization probably formed between HDPE and UHMWPE. Moreover reducing heating rate didn't make the single endotherm separate. The enhancing of diffractive strength on 110 and 200 crystal face manifested that the UHMWPE molecular chains taken part in the crystallization of the blends. Reducing of the diameter of the undissolved UHMWPE particles in LM manified that the dispersion of UHMWPE in the blends obviously improved. Therefore two-step processing way could improve the dissolved degree and contribute to form the cocrystallization.
Poly (Ethylene-Co-Vinyl Acetate)/ Magnetite Nanocomposites: Interaction of Some Liquid Fuels, Thermal and Oil Resistance Studies
Authors: Ramesan M.T.
Published: September 2018

Nanocomposites of poly (ethylene-co-vinyl acetate) (EVA) with magnetite (Fe3O4) particles were prepared in a laboratory size two roll mixing mill. The extent of interaction of nanoparticles in EVA was studied by X- ray diffraction (XRD), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). XRD patterns showed that the nanoparticles enhanced the crystalline nature of the polymer. Composite with 7 parts per hundred (phr) of Fe3O4 showed the uniform dispersion of nanoparticles in the EVA phase. The TGA result showed that the decomposition temperature of EVA/ Fe3O4 nanocomposites was much higher than the decomposition rate of pure EVA. Petrol, diesel and kerosene sorption by nanocomposites in the temperatures range of 28 to 50 °C have been investigated. The minimum solvent uptake was obtained for the composite with 7 phr of filler and the value increased with increase in concentration of nanoparticles was due to the aggregation of nanoparticles at higher loading. Diesel showed the lowest interaction with composites compared to petrol and kerosene. It was found that the temperature activates the diffusion and the activation parameters were calculated. The oil resistance properties of the nanocomposite were higher than that of EVA and resistance to oil increased with increase in concentration of nanoparticles.
Preparation, Mechanical and Thermal Properties of Poly(Butylene Terephthalate) and Its Nanocomposites Prepared from Cyclic Butylene Terephthalate
Authors: Yang Bin , Zhou Limin , Zhang Jifeng , Zhang Lu
Published: September 2018

Polymerized cyclic butylene terephthalate (pCBT) casts and pCBT/nano-silica composites generated from cyclic butylene terephthalate (CBT) were manufactured. The mechanical properties of pCBT casts with various ratio of catalyst were investigated through three-point bending test, and the thermal properties of the samples were tested by differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). Moreover, the fracture morphologies of pCBT as well as its nano-silica composites were observed by SEM. From the study, suitable catalyst content for CBT resin was determined and pCBT/nano-silica composites were found to have better thermal performances compared with neat pCBT.
Temperature Dependence of Tack for Polyacrylic Block Copolymer/Tackifier Blend
Authors: Shitajima Kohei , Karyu Nozomi , Takada Kyohei , Fujii Syuji , Nakamura Yoshinobu , Urahama Yoshiaki
Published: September 2018

The effect of polymer and tackifier compatibility on tack of pressure-sensitive adhesive (PSA) tape was investigated. Poly(methyl methacrylate)-block-poly(butyl acrylate)-block-poly(methyl methacrylate) triblock copolymer was used as the base polymer and three types of tackifiers, an aliphatic petroleum resin (A), a special rosin ester resin (B), and a rosin phenolic resin (C), were mixed at 10–30 wt.%. Compatibility with the base polymer was greater in the order of C > B > A. Tackifier agglomerates of approximately 10 nm were observed by transmission electron microscopy for the PSA with tackifier C. Similar agglomerates were observed for tackifier B, but the size increased with content. The size for tackifier A was several tens of micrometers. Dynamic mechanical analysis indicated that the glass transition temperature of the poly(butyl acrylate) phase increased upon addition of tackifiers B and C. This trend was more significant for tackifier C. It was not observed for tackifier A. The temperature dependence of tack was measured using a probe tack test. Tack was greater in the order of C = B > A. Tack at higher temperatures was superior for greater tackifier C contents. Tackifier and base polymer compatibility has a strong effect on tack and its temperature dependence.
Experimental Study on the Mechanical Properties of Basalt Fibres and Pultruded Bfrp Plates at Elevated Temperatures
Authors: Lu Zhongyu , Xian Guijun , Li Hui
Published: September 2018

Basalt fibre reinforced polymer (BFRP) composites have been widely used for structural strengthening and reinforcement in civil engineering recently. Since fire risk is unavoidable for most civil structures, the degradation of BFRP at elevated temperatures needs to be known for the safe design of its strengthened or reinforced structures under fire risk. In this study, the mechanical properties of basalt fibre roving and pultruded basalt fibre reinforced epoxy plates were investigated at elevated temperatures. As the temperatures increasing from room temperature to 200 °C, the tensile strength and modulus of the fibre roving were reduced by 8.3% and 9.7%, respectively. Meanwhile, the Weibull shape parameter (m) of the fibre roving decreased by 20.5%. As regards the BFRP plates, however, the elevated temperatures show more adverse influence. The tensile strength and modulus of the BFRP plates is reduced by 37.5% and 31% as temperature rising to 200 °C. Compared to the tensile properties, the short beam shear strength (SBS) was reduced by around 90%, more susceptible to the elevated temperatures. The glass transition temperature (∼93 °C) plays a key role on the inflexion of the variation of the mechanical properties, especially for the tensile strength. In a wide temperature range, the relationship between the tensile strength and the SBS showed a good linearity, indicating the reduction of the tensile strength comes from the deterioration of the interlaminar shear strength at elevated temperatures.
The Effect of a Novel Intumescent Flame Retardant-Functionalized Montmorillonite on the Thermal Stability and Flammability of Eva
Authors: Liu Yan , Yu Qingli , Fang Zhengping , Zhang Yan
Published: September 2018

A novel intumescent flame retardant-functionalized montmorillonite (PAB-MMT) was prepared by modification of sodium montmorillonite (Na-MMT) with an intumescent flame retardant (PAB) containing phosphorus-nitrogen structure. The results of X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) analysis indicated that PAB had intercalated into Na-MMT. The applications of this fact for improving the thermal stability and flammability of poly(ethylene-co-vinyl acetate) were investigated by thermogravimetric analysis (TGA), and microscale combustion calorimetry (MCC). Scanning electron microscopy (SEM) was carried out to learn the morphology of the char residue. The results showed that the addition of PAB-MMT into EVA could improve the flame retardancy of the EVA matrix. The peak heat release rate (PHRR) and total heat release (THR) were significantly reduced in comparison with those of other EVA composites. The TGA data showed higher char residue than other composites, which was the reason for the improved flame retardancy.
Manufacture of Fibreglass Nonwoven Composites and Study of the Effect of Different Variables on Their Quality
Authors: Yousfani Sheraz Hussain Siddique , Gong R.h. , Porat I.
Published: September 2018

A new technique of manufacturing thermoset composites using chopped fibreglass strands was investigated during this research work. This technique involved manufacturing of fibreglass nonwoven webs by the wet-laid method, these webs were then used as reinforcement for making composites. The wet-laying process allows the opening of the fibreglass strands to single fibres so that the fibres are dispersed more uniformly within the composite. The in-plane fibre orientation distribution in these nonwoven webs was random and the composites manufactured from these webs have more in-plane isotropic properties.

The effect of key process variables i.e. dispersion, fibre length and multiple layering on the density, fibre content and void content of the composites was studied. It was found that layering increased the fibre content and decreased the void content. Dispersion and increase in fibre length also decreased the void content.
Modeling of Voids Evolution in the Encapsulation Process of Photovoltaic Modules
Authors: Li Heng-Yu , Luo Yun , Ballif Christophe , Perret-Aebi Laure-Emmanuelle
Published: September 2018

Being void-free is an important criterion for the quality control of photovoltaic (PV) modules after encapsulation. The encapsulation process of PV modules with Ethylene Vinyl Acetate (EVA) polymer is complex, due to the time-dependent processing conditions and the material properties caused by continuous heat transfer and chemical reactions such as crosslinking. Hence, an in-depth understanding on the void evolution mechanism is challenging yet critical for obtaining high-quality, durable void-free PV modules and improving their production throughput. Towards this goal, a void evolution model is proposed in order to reveal the most appropriate processing parameter windows for eliminating voids during the EVA encapsulation process. Firstly, the types and origins of the voids in PV modules are discussed. Then the pressure balance in-/outside the void is considered, to evaluate the void stability as a function of temperature and pressure in the actual encapsulation cycle. Finally, a diffusion-controlled model for the evolution of void of wet air is adapted and implemented to predict the void evolution and interpret the experimental observations throughout the encapsulation process. In the conclusion, the critical processing parameters affecting the void evolution during the encapsulation process of PV modules are highlighted.
Elastic Properties of Carbon Fibre-Reinforced Epoxy Composites
Authors: Rahmani Hossein , Najaf S. Heydar Mahmoudi , Ashori Alireza , Golriz Mahdi
Published: September 2018

The aim of this work was to investigate the prediction of the elastic constants of carbon fibre-reinforced epoxy laminated composites using a simple mathematical approach. For this purpose, a Matlab Calculation Code (MCC) has been developed in MATLAB, which provides sufficient capabilities for analysis of the mechanical behaviour of composite materials. The MATLAB code enables a variety of fibre orientation angles to be generated and a wide variety of fibre volume fractions to be analyzed under mechanical loading. In order to validate the accuracy of prediction results, a commercial grade epoxy resin (Araldite LY-5052) and unidirectional carbon fibre (Torayca T700) were used to fabricate some samples of laminated composites with cross-ply configuration using the hand lay-up method. Experimental results such as elastic modulus, tensile strength as well as elongation at break were compared with the theoretical data extracted from MCC. The theoretical analysis were verified with experimental results for the same type of composites. Although the values were different, excellent agreement in the trends of the changes was found for the two approaches. Therefore, it was concluded that the MCC is capable of predicting the elastic constants of laminated composites with a high level of confidence for a wide range of fabricating conditions. The results also showed that the tensile properties of composites made with 3-layer were generally greater than those of the other evaluated composites. This kind of behaviour may be explained by bondline defects, which adversely influence the mechanical properties.
Effect of Natural Rubber/Epoxidized Natural Rubber (90/10) on Dielectric Properties and Crystallization of Metallocene Linear Low Density Polyethylene
Authors: Alwaan I.M. , Hassan A. , Piah M.A.M.
Published: September 2018

The effects of different amounts of natural rubber/epoxidized natural rubber (90/10 NR/ENR-50) blended with metallocene linear low density polyethylene (mLLDPE) with HVA-2 compatibilizer on the permittivity, dielectric loss, breakdown and volume resistivity at frequency of 50 Hz were investigated. Increasing the voltage with a range 1-5 kV increased the permittivity of both virgin mLLDPE and its blends. The permittivity, dielectric loss and breakdown of mLLDPE continuously decreased with increasing rubber content, but the AC volume resistivity of mLLDPE continuously increased with the rubber content. The degree of crystallinity of the mLLDPE composites was determined by differential scanning calorimetry. The lowest crystallinity and the maximum density of physical cross-links were observed in 10% rubber/mLLDPE blend. Increasing the proportion of rubber decreased the melting points of the blends. The FTIR showed that the epoxy groups and double bonds were absent from all the blends while the carbonyl group appeared in all cases.
In Situ Polymerisation of Pyrrole within the Lattices of Mesoporous Hexagonal Silica Systems
Authors: Feraille Gaël , Foot Peter J. S. , Singer Richard J.
Published: September 2018

This study concerns the preparation and characterisation of electrically conducting polypyrrole-silica (PPy-Si) composites. Pyrrole monomers were adsorbed in nanoporous MCM-41 silicas exhibiting a hexagonal (H1) geometry, some of which had been functionalised using aminopropyltriethoxysilane (APS), and chlorotrimethylsilane (TMS). Composites were then produced through oxidative polymerisation and doping with anions, mainly sodium sulphonates (methylbenzenesulphate (MBSA), dodecylbenzenesulphonate (DBSA) and diethylhexylsulphosuccinate (DEHS)). An attempt to produce similar composites via direct threading of “soluble” polypyrrole was also investigated in order to study the effect of confined geometries on the growth and properties of polypyrrole chains. The final composites exhibited semiconducting properties (σ up to 10−3S. cm−1), and improved thermal and environmental stabilities, making them suitable for applications such as sensors and antistatic agents.
Effect of Filler on the Mechanical and Dynamic Properties of Impact Energy-Absorbing Materials
Authors: Frank Michal , Drdlová Martina , Prachař Vladan , Rybová Veronika , Buchar Jaroslav
Published: September 2018

Energy-absorbing materials represent an important group of products in the field of increasing the safety of citizens. Research and development including physical properties testing leads to improvement of these materials and protective constructions. Two types of fillers were chosen for testing: macro and microfillers, together with a two-component polyurethane binder. Different recipes of energy absorbing materials were tested and the resulting physico-mechanical properties, namely bulk density and flexural, compressive and impact strength, are listed in this article. Deformation curves were recorded during pressure loading of materials with macrofillers incorporated. Based on these curves, the rate and mode of energy absorption can be predicted. Most samples underwent the Split-Hopkinson pressure bar test which was the crucial method for the determination of impact energy absorption.
Organo-Montmorillonite Modified Bismaleimide as Matrix in Carbon Fibre-Reinforced Composites
Authors: Li Wei , Zhou Bao Quan , Zhao Huan Wei , Wang Ming Yu , Ren Rong
Published: September 2018

Two types of organo-montmorillonite (OMMT) modified bismaleimide (BMI) nanocomposites based on 4,4'-bismaleimide diphenyl methane (BDM) and O,O'-diallyl bisphenol A (DBA) have been synthesized. A compression moulding process was used to fabricate carbon fibre-reinforced OMMT/BMI multiscale composites. X-ray diffractometry (XRD) and transmission electron microscopy (TEM) indicated that the silicate layers of OMMT were partially exfoliated and dispersed uniformly in the nanocomposites. The study showed that the interlaminar shear strength (ILSS) and flexural properties of the carbon fibre composites were improved by the incorporation of OMMT. The maximum increment of the ILSS, flexural strength and elastic modulus of carbon fibre composites were 19.09%, 38.26% and 26.97%, respectively. Scanning electron microscope (SEM) photographs revealed that the destruction modes of carbon fibre composites were also changed after the OMMT was introduced into the composites system.
Mechanical Behaviour of Sorghum Stalk Rind Reinforced Maleic Anhydride Grafted Polyethylene under Different Environmental Conditions
Authors: Bakeer Bahi , Taha Iman , El-Mously Hamed
Published: September 2018

This work investigates the mechanical and service behaviour of high-density polyethylene composites reinforced by sorghum stalk rind (SSR) at various concentrations of fibres and maleic anhydride treated polyethylene (MAPE). Fibre length l and aspect ratio l/w distributions of compounded fibre composites show large numbers of smaller particles. Tensile and bending properties were investigated, taking the effects of some service conditions into consideration, such as water absorption and UV exposure. Untreated polyethylene reinforced with 40 wt.% SSR showed a maximum water uptake of 6.9 wt.%. Generally, reductions in strength and modulus were observed upon immersion in water. In contrast, UV radiation did not show any significant effect on mechanical properties at exposure times of up to 300 h.
A Combined Experimental and Molecular Dynamics Simulation Study on the Miscibility of Eucommia Ulmoides Gum with Several Rubbers
Authors: Li Fei-Zhou , Lu Zhen-Lin , Tian Dong-Ping
Published: September 2018

This paper analyzes the miscibility state of EUG blended with CR, BR, SBR, NR and NBR via Molecular Dynamics (MD) simulations performed using Blends and the Flory-Huggins interaction parameter, phase diagrams, and mixing energy. The results showed that EUG can be miscible with CR, BR, SBR, NR, and NBR above 350K, and the simulation predictions and experimental results were mainly the same.
Highly Efficient Encapsulation of Ingredients in Poly(methyl methacrylate) Capsules Using a Superoleophobic Material
Authors: Takei Takayuki , Araki Kiyotaka , Terazono Keita , Ozuno Yoshihiro , Hayase Gen , Kanamori Kazuyoshi , Nakanishi Kazuki , Yoshida Masahiro
Published: September 2018

Increasing the efficiency of encapsulation of ingredients into spherical capsules can decrease the manufacturing costs of the capsules. Ingredients can be encapsulated with high efficiency (>99%) into nondegradable hard resin capsules prepared by polymerization of spherical droplets of trimethylolpropane trimethacrylate (TRIM) monomer placed on a superoleophobic material. Poly(methyl methacrylate) (PMMA) resin is a more versatile capsule material than poly-TRIM resin. In this study, the efficiency of encapsulation in PMMA resin capsules prepared from methyl methacrylate (MMA) monomer was investigated. To reduce the volatility of the MMA monomer, pre-polymerized MMA was used for capsule preparation. Although non-volatile α-tocopherol and doxorubicin could be encapsulated in the capsules with high efficiency by heat polymerization at 60°C for 3 h, the efficiency for volatile tetradecane was much lower (approximately 60%) because it evaporated. Furthermore, even when using pre-polymerized MMA, more than 70% of the prepolymer evaporated during polymerization. To prevent the evaporation of tetradecane and the prepolymer, ultraviolet photopolymerization was adopted because it was faster and could be conducted at a lower temperature. The photopolymerization prevented the evaporation of the prepolymer and increased the efficiency of encapsulation of tetradecane (approximately 90% efficiency). This polymerization system is effective for encapsulation of ingredients in PMMA capsules with high efficiency.
Preparation and Characterization of Coloured Polymer Particles for Electronic Ink
Authors: Wang Jing , Feng Yaqing , Li Xianggao
Published: September 2018

A new coloured polymer particle was prepared, in which chromophoric groups were introduced onto the surface of the polymer particle for use in electronic ink. The structure, morphology and thermal stability of polymer electrophoretic particles were characterized using FTIR, solid state 13C-NMR, SEM and TGA. Electrophoretic mobility measurements proved that the polymer particles had negative charges in the electrophoretic dispersion medium. Electronic ink microcapsules containing the polymer particles were prepared by coacervation. The polymer particles had a reversible electric response in the microcapsules under a DC electric field.
Optimization of Machining Process Parameters in Drilling of CFRP Using Multi-Objective Taguchi Technique, TOPSIS and RSA Techniques
Authors: Shunmugesh K. , Panneerselvam K.
Published: September 2018

Carbon Fiber Reinforced Polymer (CFRP) are widely used in many engineering applications as replacement for various other elements to make use of the advantage of its high strength-weight ratio, durability and high corrosion resistance. The paper herein is an attempt to evaluate the drilling characteristics of CFRP by means of three different drill bit types (HSS, TiAlN and TiN) using Taguchi L27 (313) orthogonal array under dry condition. Firstly, the machining process parameters (cutting speed and feed rate) are optimized with multiple performance characteristics using Multi-objective Taguchi technique and TOPSIS. Secondly, mathematical model is developed to correlate the machining process parameters and the performance characteristics (surface roughness, circularity and cylindricity) using response surface analysis. ANOVA is used to validate the developed mathematical model of the responses. The investigation reveals that the results of TOPSIS technique are in good agreement with the multi-objective Taguchi technique and also feed rate is the most predominant factor which affects the responses.