bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen Adsorption on Ca-Decorated Epoxy-Coating Graphene
Authors: Liu Wenbo , Liu Yang , Hao Lifeng , Xu Zhonghai , Yang Fan , Zhu Zhenqiang , Wang Rongguo
Published: September 2018

The hydrogen adsorption of calcium-decorated epoxy-doped graphene has been studied by density functional theory calculations. Several models are set up and the optimized geometries are obtained. The interaction among epoxy functional groups, graphene and metal atoms is studied by analyzing the electronic and band structures of the relaxed models. Mulliken population and the partial density of states are calculated to probe the nature of hydrogen molecules adsorption on this system. Our results demonstrate that this kind of stable material can be used as a promising hydrogen storage material.
Mechanical Parameters Determination of a Polymeric Membrane by Digital Image Correlation
Authors: Guochang Lin , Huifeng Tan , Xianghong Bai
Published: September 2018

Digital image correlation (DIC) is a powerful method for full-field strain test of polymeric materials and speckle pattern on the material's surface is a critical factor for the measurement accuracy. In this paper, a new speckle pattern technique is presented and used on mechanical parameter determination of a thin and soft polymeric membrane. The presented speckle pattern is generated by combination of image noise technology and film printing technique, and it is much easier to get fine speckle pattern compared with traditional spray speckle pattern technique which is a hard and time-cost work. To verify the validity of the presented speckle pattern technique, Young's modulus and Poisson's ratio are measured by presented speckle pattern and spray speckle pattern on a tensile testing machine. It is found that the measurement results by presented speckle pattern agree well with that by fine spray speckle pattern. With the presented speckle pattern technique, DIC becomes a more convenient and fast non-contact measurement technology for polymeric materials test.
Numerical Analysis for the Interlayer Toughening of Piezoelectric Smart Composite Plate
Authors: Rui-xiang Bai , Haitong Bai , Mingchao Wang
Published: September 2018

The piezoelectric composite material could engender stress concentration resulting from small cracks during layers easily, as the cracks growth will lead to the failure of the whole structure. In this paper, a finite element model for piezoelectric composite materials by ABAQUS including interlayer crack was established, and the J integral and crack tip stress of different types PZT patches were calculated by using the equivalent integral method. Then, the J integral for adhesive layers with different thickness, elastic modulus considering and not considering piezoelectricity was investigated. The results show that the J integral of mode I, II reduces with thicker adhesive layer and lower elastic modules, and the J integral of mode II decreases more sharply than that of mode I.
Development of Filament Wound Composite Isotensoidal Pressure Vessels
Authors: Zu Lei , Koussios Sotiris , Beukers Adriaan , Zhang Dinghua
Published: September 2018

Filament wound isotensoidal structures are recently gaining more attention for designing composite pressure vessels. In this paper we present the governing equation for creating geodesic-isotensoids based on the netting theory and geodesic winding law. The feasible intervals of the isotensoid-based design are also determined. The isotensoid-based dome profiles are determined by solving the governing equation with geometrical and initial winding conditions. When the applied axial load reaches a certain magnitude, the isotensoidal toroids can be obtained by forcing the isotensoid-based dome profile to become closed. The comparisons of the cross-sectional shapes between the isotensoidal dome and the hemispherical dome, and between the isotensoidal toroid and the circular toroid, are performed to demonstrate the preferable performance of the isotensoids. It is concluded that the isotensoid-based design leads to uniform fiber tension throughout the whole shell and the resulting structure can thus be considered as optimal for a pressure vessel. In addition, the isotensoid-based profiles show lower aspect ratios than the conventional vessel profiles under the given volume and internal pressure. Therefore the structural performance and the conformability to limited-height storage space of pressure vessels can be improved using the isotensoid-based design.
A Study on the Nondestructive Evaluation of Carbon/Carbon Brake Disks Using Infrared Thermography
Authors: Shin Hee Jae , Cha In Pyo , Lee Min Sang , Ko Sun Ho , Kim Hong Gun , Kwac Lee Ku
Published: September 2018

Carbon/carbon brake disks that use carbon fibers impregnated in a carbon matrix are widely utilized in aircrafts and automobiles owing to their high strength, high heat conductivity, low density, and excellent overall mechanical properties. Carbon/carbon brake disks are high cost products and require multi-process manufacturing. The safety and material efficiency of defective products reduces significantly and nondestructive testing is required to monitor the quality, homogeneity, and integrity of the material. In general, radiographic evaluations pose safety problems owing to the use of radiation in such evaluations and ultrasonic flaw detection is difficult to use because of its dependence on the surface of the specimen. This study uses an infrared thermography camera technique, which is not influenced by the sample surface, to monitor the heterogeneity of materials during the manufacturing process and to thus prove the reliability of the method.
Crystallization Behavior of Thermotropic Liquid Crystalline Polymer Reinforced Polyamide 66 in Situ Composites
Authors: Yue Qunfeng , Zhu Chuncheng , Yang Shengrong
Published: September 2018

This paper studies the non-isothermal crystallization kinetics of polyamide 66 (PA66) and thermal liquid crystal polymer (TLCP) in situ composites with contents of TLCP is 1 wt.% by differential scanning calorimetry (DSC) at various cooling rates. The results show that TLCP acts as nucleator for PA66 matrix accelerating the crystallization. It is speculated, from Avrami exponent and Liu method, that there is a strong hydrogen bonds between –NH-, -CO- groups of PA66 and -COOH and/or -OH groups of TLCP. Kissinger method is employed to obtain the activation energy of the crystallization process and the results indicated that the addition of TLCP may entice the crystallization of PA66 matrix.
Piezoelectric Modal Damping Performance of 0-3 Piezoelectric Composite with Conducting Phase: Numerical Analysis and Experiments
Authors: Zhang Hongming , He Xiaodong , Yang Fan , Hao Lifeng , Xu Zhonghai , Wang Rongguo
Published: September 2018

The piezoelectric modal damping performance of 0-3 piezoelectric composite is discussed in this paper. The piezoelectric damping consisting of PZT piezoelectric ceramic, epoxy (EP) and electric carbon black (CB) is analyzed by a numerical prediction method. The finite element analysis (FEA) method is used to predict the effective property of the 0-3 piezoelectric composites. And then the shunted piezoelectric theory is applied to predict the piezoelectric modal damping of 0-3 piezoelectric composites. The results show that the numerical results are accurate to predict the piezoelectric modal damping compared to the experimental results. Doping appropriate amount of CB can improve the damping of 0-3 piezoelectric composite. This work will help to predict the value of piezoelectric modal damping of the 0-3 piezoelectric composite and to optimize the damping design.
Experimental Study of the Electrical Resistivity of Glass-Carbon/Epoxy Hybrid Composites
Authors: Liu Xin , Wu Zhanjun , Wang Rongguo , Yan Jia
Published: September 2018

The electrical resistivity of composite materials varies with the changing of structural parameters, and this feature could be used to improve their electromagnetic wave absorbing property. This work investigated the electrical resistivity of hybrid composites aiming at radar absorbing structures. The glass-carbon/epoxy hybrid composites with different structural parameters were prepared by filament winding machine. And the effects of hybrid style, hybrid ratio, curing pressure, fiber distribution and fiber orientation on electrical resistivity were tested. As the test results shown, firstly, the electrical resistivity of interlaminated hybrid composites is larger than that of intraply hybrid composite; secondly, the electrical resistivity of hybrid composite is inversely proportional to the content of carbon fiber; thirdly, the electrical resistivity of hybrid composite with carbon fiber homogeneous distribution is larger than that of hybrid composite with inhomogeneous distribution; finally the electrical resistivity of hybrid composite would decrease with the curing pressure increasing. Interestingly there are similar rules in the vertical and parallel direction of the fibers. These results are helpful to control and adjust the electrical resistivity of glass-carbon/epoxy hybrid composites.
Thermal Aging Behavior of Carbon Fiber/Epoxy Composites at High Temperature
Authors: Wang Rongguo , Jiang Long , Xu Zhonghai , Yang Fan , Hao Lifeng , Jiao Weicheng , Liu Wenbo
Published: September 2018

To investigate the thermal aging mechanism of carbon fiber/epoxy composites under high temperature (around 110 °C), the present study examined the inter-laminar shear properties and curing degree. Experimental results showed the inter-laminar shear strength of carbon fiber/Epoxy composites firstly increased following with the aging time increase which caused by secondary cure, then reduced for long-term of thermal stresses. Fourier transform infrared spectroscopy analysis revealed that the hydroxy functional groups had a certain growth which confirmed that secondary cure occurred during thermal aging. Electron paramagnanetic resonance results indicated that the increase of the intensity of free-radicals may cause by the chain breaking. Also scanning electron microscopy (SEM) images of fracture surface indicated that carbon fiber and matrix had well combination, which contributed to the better residual shear properties.
Optimal Design of Lightweight Composite Pressure Vessel by Using Artificial Immune Algorithm
Authors: Jiao Weicheng , Niu Yue , Hao Lifeng , Yang Fan , Liu Wenbo , Wang Rongguo
Published: September 2018

This research aims to optimize the weight of composite overwrapped pressure vessel (COPV) under internal pressure. In the paper, a new design method based on the clonal selection principle in the biological immunology is proposed to solve the minimum weight problem under the burst pressure constraint. The method consists of three main parts: the non-geodesic path algorithm, variable stiffness analysis algorithm and artificial immune algorithm. A software called SimWind 1.0 was developed on the basis of this method in order to design the composite pressure vessel rapidly and efficiently. Finally, a representative carbon fiber composite pressure vessel with ultrathin Al liner was designed and fabricated by using this new design method and the software.
Mechanical Properties of Self-Healing Carbon Fiber-Epoxy Composite Stitched with Mendable Polymer Fiber
Authors: Yang T. , Du Y. , Li Z.M. , Wang C.H.
Published: September 2018

Carbon fiber composites are self-healed by advance embedding of repairing agents in the composites. However, the repairing agent will influence the mechanical properties of the carbon fiber composites. In this study, poly(ethylene-co-methacrylic acid) (EMAA) filaments were stitched into carbon fiber-epoxy laminates to create a three-dimensional (3D) self-healing fiber system. Specimens with unmodified and self-healing laminates were manufactured. The mechanical properties of the carbon fiber-epoxy composite stitched with mendable polymer fiber for self-healing and unmodified laminates were compared experimentally. Results from the double cantilever beam test revealed that the stitched EMAA fibers increased the mode I interlaminar fracture toughness of the laminate by ∼120%. However, short-beam shear (SBS) strength of the composite laminates with the healing agents was slightly degraded, with a 37% reduction in the average SBS strength. The compressive-after-impact assessment showed that the strength was reduced by 6.6%. C-Scan revealed the 3D inter-connected self-healing EMAA network within the composite laminates.
Simulation and Experimental Study on Micro-Crack Toughening Mechanism for Attapulgite/Epoxy Nanocomposite
Authors: Zhang Jian , Liu Wen-bo , Hao Lifeng , Yuan Feng , Xu Zhonghai , Yang Fan , Wang Rongguo
Published: September 2018

The main purpose of this article is to study the effect of adding attapulgite nanoparticle into the polymer on micro-crack toughing. Commercial softwares Abaqus and ANSYS were utilized to simulate the stress field and the crack expanding condition in the attapulgite/epoxy composite. The pure polymer and the nanoparticle modified polymer were prepared to investigate the effect of the nanoparticle on the crack conditions of the composite. The simulation results showed that the nanoparticle enhanced the polymer by the stress field concentration around the nanoparticle which consumed more energy, made the matrix absorb less deformation energy, and hindered the extension of crack. The result of tensile experiment indicated that the tensile property was improved by adding nanoparticle into epoxy polymer. The Scan Electric Microscope image of the fracture surface indicated that the nanoparticle changed the fracture mechanism of the composite.
Non-Isothermal Simulation of Resin Transfer Molding Process with Edge Effect
Authors: Ding Yanyu , Jia Yuxi , Dong Shuhua , Xu Yihan
Published: September 2018

The resin infiltration stage during the resin transfer molding process is complicated, which involves the edge effect, resin curing reaction and heat transfer phenomenon. In this paper, considering the edge effect, the integrated investigation on curing reaction, physical property, two-dimensional resin flow and three-dimensional temperature distribution is implemented in theory and numerical simulation. And then the evolution of coupling physical fields, such as resin temperature, curing degree and resin viscosity, is analyzed numerically. The present study is helpful for understanding the complex relationships among a variety of parameters during the reactive filling process.
Rubber Wood Fibre Based Flexible Composites: Their Preparation, Physical Strength Reinforcing and Stab Resistance Behaviour
Authors: Yong K.C.
Published: September 2018

Novel flexible laminated composites based on rubber compounds and rubber (Hevea brasiliensis) wood fibres were successfully produced by using a carboxylated nitrile latex based adhesive system. All these laminated composites exhibited good reinforcing behaviour and strong elastomeric features. They also had a medium level of stab resistance strength, particularly for the “edged blade” protection class according to the standard issued by the United States – National Institute of Justice. Hence, this type of laminated composite could potentially be targeted for anti-stab body armour applications.
Production of Micrometer-Sized Composite Polymer-Magnetic Spheres Using as Precursor Metallurgical Wastes
Authors: Perera-Mercado Y.A. , Betancourt-Galindo R. , Saucedo-Salazar E.M. , Puente-Urbina B.A. , Medellín-Banda D.I. , Neira-Velázquez M.G. , Gutierrez-Villarreal M.H. , García-Rodríguez S.P.
Published: September 2018

Micrometer-sized composite polymer-magnetic spheres consisting of a magnetic-spherical core with a polystyrene shell were produced. The magnetic-spherical core was produced by plasma thermal conversion of waste powders precursor (iron oxide) generated during the conventional process of steel production. Precursor powders were projected into an Ar-He plasma plume using industrial thermal-spray equipment. The results are a total conversion of the precursor powders into magnetic-spherical particles with diameters in the micrometer size range. The surfaces of the magnetic-spheres were functionalized by a chemistry hydrolysis method using 3-aminopropyltrimethoxysilane (APTMS) and creating superficial amine structures that improved the adherence of the final polystyrene shells that was polymerized by adapting the miniemulsion process. The products at the different synthesis steps were characterized by diverse techniques, such as: X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), X-ray energy dispersive spectroscopy (EDS), Fourier Transformed Infrared spectroscopy (FTIR) and the magnetic properties were investigated with a vibrating sample magnetometer.
Thermal Conductivity and Mechanical Properties of Carbon Black Filled Silicone Rubber
Authors: Wang Jibin , Li Qiuying , Wu Chifei , Xu Haiyan
Published: September 2018

The effects of two types of carbon blacks (CBs), N990 and Vulcan XC-72, on the mechanical properties and thermal conductivity of filled silicone rubber (SR) were investigated. It was found that the addition of CB particles increased the thermal conductivity, the thermal stability and the tensile strength of the silicone rubber composites. The scanning electron microscope showed that Vulcan XC-72 of higher structure was more liable to form conductive network within the matrix, and the thermal conductivity of the composites filled by Vulcan XC-72 was superior to that of the composites filled by N990 at the same filler loading. The Agari model and the Payne effect were used to explain the influence of N990 and Vulcan XC-72 on the formation of thermal conductive networks. Furthermore, Vulcan XC-72 also had better enhancing effects on the mechanical properties and the electrical conductivity of the composites. It was notable that at the high filler contents, silicone rubber filled with N990 also possessed good general properties.
Adsorption Properties of Crosslinked Starch Microspheres toward Pyridine
Authors: Miao Zongcheng , Zhao Yang , Huo Xiaoping , Wang Lei , Li Zhongjin
Published: September 2018

The adsorption of pyridine onto crosslinked starch microspheres (CSMs) was investigated by experimental and theoretical methods. The adsorption capacity of CSMs towards pyridine increases with the increasing of pyridine concentration, and by lowering the temperature, adsorption would be accelerated. The adsorption behaviour of CSMs to pyridine is in agreement with the Langmuir isothermal equation. The research results show that the adsorption process is exothermic, and the adsorption force mainly derives from enthalpy changes. The thermodynamic parameters of adsorption process show that the adsorption behaviour of CSMs towards pyridine is of a physical type.
Novel Superabsorbent Composite (Aa-G-Xg/Ommt) and Application in Sandy Soil
Authors: Miao Zongcheng , Wang Lei , Zhao Yuzhen , Liang Pengxia , Li Zhongjin
Published: September 2018

In order to develop an environmentally friendly polymer, a novel superabsorbent composite (SAC) was prepared by graft copolymerization of acrylic acid (AA) onto xanthan gum (XG) and then hybridization with organic montmorillonite (OMMT) by hexadecyl trimethyl ammonium bromide. The characterization of the SAC was confirmed by FTIR, SEM and DSC. Moreover, the water-retention characteristics of the composite were further studied. The results showed that the synthesized composite effectively increased the water-retention capacity. Therefore, this new composite could be considered as an excellent candidate for various industrial applications.
Effect of Sic Volume Fraction on Properties of Sic/6061 Composites
Authors: Li-peng Yan , Ai-qin Wang , Jing-pei Xie , Shi-ming Hao
Published: September 2018

The SiC/6061 composites were produced by powder metallurgy method, with the SiC particle volume fraction being 20%, 25%, 30% respectively. The microstructures of the materials were observed by Optical Microscope. The tensile strength and Coefficient of thermal expansion (CTE) were examined. Turner and Kerner theoretical models were employed to analyse the CTE. The influences of the SiC particles volume fraction on the microstructures and performances were analyzed. The results show that with the increase of the SiC particles volume fraction in the composites, the clustering degree of the SiC particles increases in the matrix, and the CTE decreases which is close to the average of the Kerner and Turner theoretical model predictions, and the tensile strength increases but when the volume fraction of SiC particles exceeds the critical value of 30% the tensile strength of the composite decreases. And the strengthening mechanism of experimental materials was discussed.
Numerical Simulation of Mode-Ii Fracture of Cfrp with Toughening Interlayer Using Bilinear Cohesive Zone Model
Authors: Zhu Guowei , Qu Peng , Guo Yunli , Liu Gang , Yi Xiaosu , Jia Yuxi
Published: September 2018

The effect of interfacial toughening porous non-woven fabric (PNF) on the Mode-II fracture toughness (GIIC) of carbon fiber reinforced polymer is studied by performing end notched flexure tests. The PNF with a thickness of 10 μm is selected as the interleaf material, which is modeled by the bilinear cohesive zone model. The vertical displacement of loading points and the corresponding force are measured. The influences of the cohesive shear strength and GIIC of the toughening interlayer on the mechanical response of composites are studied. The main results are obtained as follows. The peak load increases with the increase of the cohesive shear strength, but the increasing amplitude is gradually reduced. Once the delamination propagates steadily, the influence of the cohesive shear strength can be neglected, and at the moment, GIIC of toughening interlayer plays a leading role. Furthermore, the greater GIIC of toughening interlayer is, the greater GIIC of composites and peak load are.
Effect of Tio2 Content and Process Parameters on Electrospun Poly(Acrylonitrile)/Tio2 Nanofibres
Authors: Ji Byung Chul , Rabbani Mohammad Mahbub , Bae Sang Su , Shin Jae Cheon , Yang Seong Baek , Choi Woo Seok , Park Yang Soo , Do Kook Bae , Yeum Jeong Hyun
Published: September 2018

Poly(acrylonitrile) (PAN) nanofibres containing variable amounts of titanium dioxide (TiO2) were successfully electrospun under different conditions to find optimum electrospinning conditions and to investigate the effects of TiO2 content and electrospinning parameters on the morphologies and thermal properties of PAN/TiO2 nanofibres. Various amounts of TiO2 were dispersed separately into PAN solutions. N, N'-dimethyl formamide (DMF) was used as a solvent. Electrospinning parameters such as applied voltage and tip to collector distance (TCD) were varied at a fixed PAN/TiO2 mixing ratio. The PAN/TiO2 nanofibres containing different amounts of TiO2 were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The results showed TiO2 content and electrospinning parameters have direct influence on the morphologies of PAN/TiO2 nanofibres. Moreover, the addition of TiO2 significantly improved the thermal stability of the PAN nanofibres.
Effect of Sulfate Ion on the Performance of Polycarboxylate Comblike Copolymers in Cement Suspensions
Authors: Ran Qianping , Qiao Min , Yu Yinhui , Liu Jiaping
Published: September 2018

Polycarboxylate comb-like copolymer (PCE) is a kind of polyelectrolyte, which is easily affected by the ions in cement suspensions. In this work, the effects of sulfate ion on the surface charge, adsorption and dispersion in cement system with PCE as dispersant were investigated in detail. The addition of sulfate ion apparently decreased the positive charge on the surface of cement particles. The sulfate ion reduced the adsorption and dispersibility of PCE in cement suspensions, which was due to the competition between sulfate ions and PCE in the adsorption behaviour on the surface of cement particles.
Crystallization Kinetics of Recycled High Density Polyethylene and Coffee Dregs Composites
Authors: Cestari Sibele Piedade , Mendes Luis Claudio , Altstädt Volker , Mano Eloisa Biasotto , da Silva Daniela França , Keller Jan-Hendrik
Published: September 2018

High density polyethylene (HDPE) – coffee dregs (COFD) composites were studied over a range of seven different temperatures, under isothermal crystallization conditions, using differential scanning calorimetric (DSC) analysis. The aim was to observe the influence of filler content in the crystallization kinetics of HDPE. Seven blends were prepared, the polymer-filler ratio ranging from 100-0 to 40-60%. The results were evaluated using the Johnson-Mehl-Avrami-Kolmogorov equation. The equilibrium melting temperature was determined by applying the Hoffman-Weeks method. The materials were also evaluated through scanning electron microscopy, differential scanning calorimetry and thermogravimetry/derivative thermogravimetry.
A New Silica-Rich Material from Waste Fly Ash – Generation, Characterisation and Study of Its Effectiveness as a Filler for Rubber Compounds
Authors: Dasgupta Mridul , Gupta Saikat Das , Mukhopadhyay Rabindra , Bandyopadhyay Abhijit
Published: September 2018

A silica-rich material was generated from waste fly ash and it was subsequently characterized and experimented in ESBR compounds to find its suitability to be used as a filler for rubber compounds. This material contained 97.5% silica and 2.5% alumina. Characterisation of this material, designated as Modified Fly Ash (MFA), revealed the presence of characteristic peaks of silica in an FTIR study, and the surface area was found to be 110–115 m2/g. The effect of this material as a filler for rubber compound has been studied in ESBR compounds at low, medium and high filler loadings, and the compound properties were compared with those of compounds filled with two commercially available grades of silica, namely VN2-Silica (surface area 120–125 m2/g) and VN3-Silica (165–170 m2/g), at similar loadings. MFA showed the highest cure rate index, elongation at break and lowest heat generation among the three fillers at all the levels of filler loading. The tensile strength and 300% modulus of MFA filled compounds were inferior to those of VN3-silica, but they were closer to the values obtained for VN2-silica filled compounds. These two properties of MFA and VN2-Silica were comparable at low filler loading and at medium to high loading, the properties exhibited by VN2-Silica could be matched by using higher dosage of MFA.
Preparation of Dehydrochlorinated Poly(Vinyl Chloride) (Dhpvc) and Dhpvc Nanofibres: Effects of Reaction Time on Conductivity, Electrospinability, and Fibre Morphology
Authors: Khunsriya Phapada , Wootthikanokkhan Jatuphorn , Seeponkai Narumon , Luangchaisri Chumphon
Published: September 2018

This research work concerns the development of dehydrochlorinated poly(vinyl chloride) (DHPVC) and DHPVC nanofibres for use as components in new generation solar cells. Firstly, DHPVC with a variety of degrees of dehydrochlorination was prepared at 70 °C. The primary aim of this work was to investigate the effects of reaction time (15–105 h) on the molecular structure and conductivity of the modified PVC. In addition, the feasibility of preparing DHPVC nanofibre web via an electrospinning process was also explored. The effects of electrospinning on the morphology and conductivity of the materials were also of interest. From the results, it was found that the degree of dehydrochlorination and electrical conductivity of DHPVC are interrelated and both increased linearly with the reaction time. After carrying out electrospinning using a DHPVC sample which had been subjected to 30 h reaction time (DHPVC-30h), a randomly oriented fibre web with a smoother fibre surface and free from beads was obtained. This was not the case for the electrospun PVC and DHPVC-15h fibres. The electrical conductivity values of the electrospun DHPVC were also higher than those of the dense DHPVC film analogues. This is ascribed to an enhanced molecular alignment and a greater conjugation length of the polymer induced by the electrospinning.
Phosphate Derivative Flame Retardants on Properties of Pineapple Leaf Fiber/Abs Composites
Authors: Threepopnatkul Poonsub , Krachang Thanaphat , Kulsetthanchalee Chanin
Published: September 2018

Pineapple leaf fibers (PALF) are abundant to the agricultural products which are native to the tropical climate region. It also exhibit excellent tensile strength and tensile modulus. Acrylonitrile butadiene styrene (ABS) copolymer possess several prominent properties such as strength, rigidity and toughness. Both ABS and PALF are at high risk to the fire hazard when used in daily life. The improvement of flame retardancy of composite materials has been the priority for the safety requirements of natural fiber composite products. This research is aimed to study the effect of two different phosphate compounded flame retardants i.e., bisphenol-A bis (diphenyl phosphate) (BDP) and 9, 10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) on the flammability, mechanical and thermal properties of the composites of modified natural pineapple leaf fiber reinforced acrylonitrile butadiene styrene. 10% by weight of such PALF was compounded with ABS using diisononyl phthalate 1% w/w as plasticizer at the different flame retardant concentration (10 and 20 wt.% of ABS). The effects of flame-retardants showed that the PALF/ABS composite containing DOPO showed enhanced performance in terms of flame retardancy and even act as self-extinguisher. Higher content of flame retardants led to increase limiting oxygen index value. Moreover, DOPO added composites produced superior mechanical properties such as young's modulus and tensile strength. Furthermore, both thermal degradation temperature of PALF/ABS composites with DOPO and thermal degradation temperature of PALF/ABS composites with BDP showed relatively lower temperature than the ones of PALF/ABS composites.
Influence of Aromatic Content in Rubber Processing Oils on Viscoelastic Behaviour and Mechanical Properties of Styrene-Butadiene-Rubber for Tyre Tread Applications
Authors: Chokanandsombat Yotwadee , Sirisinha Chakrit
Published: September 2018

In the present study, experiments have been carried out to investigate the effects of aromatic and polycyclic aromatic compounds (PCAs) contents in rubber processing oils (RPOs) on the processability and mechanical properties of styrene butadiene rubber (SBR) compounds and vulcanisates. Results obtained suggest that, as expected, the presence of RPOs leads to a decreased compound viscosity, and thus an enhanced processability. By incorporating the RPOs into SBR compounds, some mechanical properties, including elongation at break and tear strength, of cured SBR can be improved, particularly for the RPOs with high aromatic content. This is believed to be attributed to the increased compatibility of aromatic containing RPOs and the SBR matrix. Nevertheless, the aromatic and PCA contents play an insignificant role on the crosslink density and bulk viscosity of the rubber compounds as well as the hardness and compression set of the rubber vulcanisates.
Development of Hyperelastic Model for Natural Rubber Containing Weldlines
Authors: Chookaew Watcharapong , Mingbunjerdsuk Jirachai , Jittham Pairote , Patcharaphun Somjate
Published: September 2018

Several constitutive models of non-linear large elastic deformation based on strain-energy-density functions have been developed for hyperelastic materials. These models, coupled with the Finite Element Method (FEM), can effectively utilized by design engineers to analyze and design elastomeric products operating under the deformation states. However, due to the complexities of the mathematical formulation which can only obtained at the moderate strain and the assumption of material used for the analysis. Therefore it is formidable task for design engineer to make use of these constitutive relationships. In the present work, the strain-energy-density function of natural rubber part containing a weldline was constructed by using the Neural Network (NN) model. The analytical results were compared to those obtained by Neo-Hookean, Mooney-Rivlin, Ogden models. Good agreement between developed NN model and the existing experimental data was found, especially at very low strain and at very high strain.
Synthesis and Thermal Stability of Crosslinked Carbazole-Substituted Poly(Dimethylsiloxane) for Led Encapsulation
Authors: Nordin Norhuda Hidayah , Ramli Mohamad Riduwan , Othmanand Nadras , Ahmad Zulkifli
Published: September 2018

A series of carbazole substituted poly(dimethylsiloxane) (PDMS) was synthesized by hydrosilylation reaction of 9-vinyl carbazole into PDMS structure. It was then crosslinked with vinyl trimethoxysilane by condensation reaction. The fabricated product increased in refractive index with increasing carbazole content. The higher carbazole content also produced high thermal stability with an increase in Tg and degradation temperature. This behaviour owe much to the carbazole moiety as well as the formation of crosslink network These features contribute to potential use as electronic devices encapsulants and coatings.
Effect of Organoclay Incorporation on Mechanical, Barrier and Thermal Properties and Anti-Bacterial Performance of Pla and Pla Composites with Triclosan and Wood Flour
Authors: Prapruddivongs C. , Sombatsompop N. , Jayaraman K.
Published: September 2018

Polylactic acid (PLA) is a biodegradable polymer which has a wide range of applications; in this work, all PLA based composites formulations were compounded by twin screw extruder and testing specimens were produced. This article focuses on determinations of mechanical, antibacterial, thermal and barrier properties of PLA composites. It was found that only the tensile modulus of PLA composites increased while the others decreased when 10% wood was loaded. The effect of Triclosan and Cloisite® 30B compounding did not change the mechanical properties and glass transition temperature. However, by the presence of wood and Cloisite® 30B, Tm values of the composites exhibited double peak characteristic which was related to an increase in crystallinity level. Antibacterial activity of the PLA composites was improved with the Cloisite® 30B content, and this was attributed to cationic bactericide quaternary ammonium group between the silicates layers. Hydrophobic material Triclosan obviously changed water vapor permeability (WVP) of the PLA from 8.24 × 10−11 to at 7.26 × 10−11 g.mm/mm2.h.Pa for triclosan/PLA specimens. All PLA composites samples with 0.5% clay content showed a significant increase in oxygen barrier property.
Experimental and Theoretical Study on the Seismic Performance of Corroded Rc Circular Columns Strengthened with Hybrid Fiber Reinforced Polymers
Authors: Li Jianhui , Li Ying
Published: September 2018

Corroded RC columns do not possess necessary ductility to dissipate seismic energy during a major earthquake, the study investigates the use of hybrid fiber reinforced polymer (HFRP) wrapping as a method of retrofitting non-ductile corroded RC columns, the seismic performance of corroded RC circular columns strengthened with HFRP are tested under cyclic load and constant axial, and a model to determine the envelope response of RC corroded columns strengthened with HFRP are presented based on cross-section analysis for undamaged RC element. Results show that the rebar corrosion may introduce the reduction of seismic performance for RC columns in some extent, and the technique of strengthening corroded RC column with HFRP is quite effective, ductility and energy dissipation are improved significantly, but the bearing capacity can be only increased within limits. The envelope curve estimated using the linear plane assumption with modification by rebar slip model, may still be used as the envelope curve of RC corroded columns strengthened with HFRP, a good agreement between analytical and experimental results is observed.
Energy Release Rate of Interface Crack in Rc Beams Strengthened with Fiber Reinforced Polymer under Four Point Bending
Authors: Jian-he Xie , Kun-hong Huang , Yong-chang Guo , Zi-jian Li , Ming-yu Cui
Published: September 2018

A popular method for strengthening reinforced concrete (RC) beams is to bond fiber reinforced polymer (FRP) plates to the soffit. An important failure mode for such retrofitted members is debonding of the FRP plates from the member due to high interfacial stresses near the intermediate crack. Accurate prediction of the energy release rate of interface crack between FRP and concrete is a prerequisite for designing against debonding failure. In this paper, a theoretical analysis was conducted to investigate the energy release rate of interface crack embedded in the FRP-plated RC beam subjected to four point bending. A mechanical analysis model including the consideration of the major flexural crack and tension steel reinforcement was established for the interface crack tip of plated RC beam. The deflection of the FRP-plated RC beam and the axial force in the plates were analyzed on the basis of the classical beam theory. The compliance of plated RC beam was derived before the tension steel yielding, and a theoretical solution of the energy release rate was then proposed. Moreover, numerical results based on the proposed theoretical model were presented to illustrate the effects of various parameters on the energy release rate of interface crack in the plated RC beam.
Mechanical Properties of Polymer Rubber Materials Based on a New Constitutive Model
Authors: Sang J.B. , Sun L.F. , Xing S.F. , Liu B.H. , Sun Y.L.
Published: September 2018

A new constitutive model, which is a modification from Gao's second constitutive model, has been introduced by using the finite deformation theory. The new model fulfils the condition that strain energy becomes zero under no deformation. For incompressible polymer rubber materials, when n=1 and a=0, the new constitutive relation may be simplified to the Mooney-Rivlin model; when n=1 and α=1, the new constitutive relation may be simplified to the Neo-Hookean model. The discussions of basic finite deformation examples illustrate how the new constitutive model reasonably describes the deformation properties of polymer rubber materials, and how the applied range of polymer rubber materials have been broadened by using the new constitutive model.
Characterization of Peo-X Ionic Conductive Polymer for Anodic Bonding
Authors: Yin Xu , Liu Cuirong , Nan Yue , Meng Qingsen
Published: September 2018

Anodic bonding is a common technology in MEMS packaging. However, only the bonding between glass and metal or semiconductor can be implemented at present. In this work, a new type of composite, solid polymer electrolyte (taking PEO as the matrix with a small amount of nano-sized inorganic filler), was prepared as a new anodic bonding material. We studied the interaction and conduction mechanism between PEO and the inorganic filler through DSC and XRD analyses, and also discussed the application feasibility of the solid polymer electrolyte being packaging material in anodic bonding. The results showed that adding inorganic filler can reduce the interface resistance of the macromolecule solid electrolyte, and control the diffusion of alkali metal ions in the solid lithium molecule electrolyte when under a strong electric field. The anodic bonding technique may promote the application of this new macromolecule material in MEMS.
Methodology to Analyze the Influence of Microcellular Injection Molding on Mechanical Properties with Samples Obtained Directly of An Industrial Component
Authors: Elduque Daniel , Clavería Isabel , Fernández Ángel , Javierre Carlos , Pina Carmelo , Santolaria Jorge
Published: September 2018

Microcellular injection molding is a process that offers numerous benefits thanks to the internal structure generated, thus many applications are being arising in different fields, especially home appliance. In spite of it, when changing the manufacturing process of a component from conventional injection molding to microcellular injection molding, it is necessary to ensure the mechanical properties of the component.

In this paper a study of the mechanical behavior of samples obtained directly from a manufactured component both by conventional injection molding and microcellular injection molding is carried out. This kind of samples take into account the process conditions under the final component is processed and the influence of these conditions on the mechanical properties. For this purpose special devices have been developed taking into account the characteristics of the component and the samples obtained. An X-ray 3D computed tomography is also carried out to validate the internal structure of the microcellular injection molded component.

Tensile properties are reduced between 20–22% regarding flow direction when using microcellular injection molding. Impact properties are reduced up to 27%. However, flexural properties reduction for samples processed by microcellular injection is only 6.8%, so microcellular injection molding arises as a very suitable process for components working under this kind of load. Molding and impact tests are carried out by using specially developed devices.
Evaluation of a Smart Polymer Nanosphere for Potential Use in Anticancer Drug Delivery
Authors: Vimalarasa Rubini , Foot Peter J.S. , Calabrese Gianpiero
Published: September 2018

Polypyrrole-chitosan (ppy-chit) hollow nanospheres have been synthesised using a simple route wherein dispersion polymerization of pyrrole was followed by treatment with aqueous ammonia, centrifugation and dialysis. Ppy-chit hollow nanospheres were characterized by techniques including transmission electron microscopy, atomic force microscopy, powder x-ray diffractometry and UV-visible spectrophotometry. The particle size and stability were assessed by using a Zetasizer. A model anticancer drug, Nile blue chloride, was loaded into the ppy-chit hollow nanospheres by adsorption, and the desorption profile showed that 88% of the dye was released at a typical physiological pH over a period of 5 hours. The combined molecular properties of chitosan and polypyrrole were beneficial to the drug delivery.
Preparation of Core-Shell Composite Particles Containing a Dye Powder by a Droplet Coalescence Method
Authors: Taguchi Yoshinari , Isono Yu , Fuchigami Kiyomi , Kimura Isao , Tanaka Masato
Published: September 2018

It was attempted to prepare core-shell composite particles containing a hydrophilic dye powder by a droplet coalescence method using liquid-liquid dispersion.

Core particles composed of dye powder and oleic acid have been forced to coalesce with styrene monomer droplets, and then suspension polymerization has been performed to form the polystyrene shell.

In the experiment, the number and diameter of styrene monomer droplets were mainly changed stepwise to promote coalescence between the core particles and the monomer droplets and to control the shell thickness. It was found that the core shell composite particles could be prepared by increasing the monomer droplet number at the constant impeller speed, because the coalescence frequency between the monomer droplets and the core particles increased with the monomer droplet number at the constant impeller speed.

Moreover, the diameter and shell thickness of the core shell composite particles increased with the diameter of monomer droplets.
Poly(Vinyl Alcohol)/Pullulan Blend Nanofibres Prepared from Aqueous Solutions Using Electrospinning Method
Authors: Islam Md. Shahidul , Rabbani Mohammad Mahbub , Yang Seong Baek , Choi Woo Seok , Choi Jin Hyun , Oh Weontae , Shin Jae Cheon , Lee Jin Tae , Yeum Jeong Hyun
Published: September 2018

Poly(vinyl alcohol) (PVA)/pullulan (PULL) blend nanofibres were prepared from their aqueous solutions by electrospinning method. Polymer solutions with different concentrations and blend ratios were used to investigate the effect of polymer concentrations and blend ratios on the morphologies and properties of PVA/PULL nanofibres. At a fixed blend ratio, the total polymer concentrations were also adjusted to find suitable electrospinning condition for preparing uniform and bead-free nanofibres. The as-prepared nanofibres were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Their mechanical properties were also studied by measuring their tensile strength. The results showed that polymer concentrations and blend ratios have direct influence on the morphologies and properties of PVA/PULL nanofibres. 12 wt.% total polymer concentration and higher PVA contents have been found to be favourable for obtaining uniform and bead free PVA/PULL blend nanofibres with improved mechanical and thermal properties.
Enhanced Application Properties of Epdm/Montmorillonite Composites
Authors: Yi Zhao , Jincheng Wang , Youcheng Du , Chen Pan , Wen Zhao
Published: September 2018

The aim of this work was to study the effect of montmorillonite (MMT) on the flame-retardant and mechanical properties of ethylene-propylene-diene monomer (EPDM). EPDM/MMT composites were prepared by conventional compounding of EPDM matrix with MMT. The cure characteristics, tensile properties, wear resistance, thermal stabilities, and flame-retardancy were researched and compared. Optimal dispersion of this clay was observed for 10 phr of MMT filled composite, which resulted in the best mechanical performance with an increase of 85% in tensile strength, 300% in elongation at break, and 50% decrease in abrasion loss, 35 s for the prolonged vertical burning time, and the improved thermal stability, compared to that of the pure matrix. A mechanism for reinforcing and flame-retardancy was proposed. The “anchor” effect caused by the MMT may have reduced the number and size of voids in the EPDM matrix, and thus increased the crack path during tensile drawing. Meanwhile, the flame-retardant effect of MMT could increase the amount of carbonaceous layers, and thus inhibited the pyrolysis degree of EPDM matrix during burning.
Removal of Methyl Violet and Cationic Gold Yellow from Aqueous with Porous Magnetic Polymer Microspheres and Its Adsorption Kinetics
Authors: Liang Kai , Liu Qingquan , ding Yue
Published: September 2018

Porous magnetic polymer microspheres (PMPMs) were used as an adsorbent to removal of methyl violet (MV) from wastewater. Ethanol/water co-solvent mixtures in combination with various inorganic salts were used as eluents to regenerate PMPMs. The desorption capacity of the eluents were systematically investigated. The results showed that when ethanol/water co-solvents were used as the eluent, the desorption efficiency increased with the ethanol concentration. Incorporation of inorganic salts into the co-solvents greatly improved the desorption efficiency of the eluents. Among the eluents, a mixture of ethanol/water (8/2, v/v) in combination with 0.1M KCl exhibited excellent ability for recovering cationic dyes and regenerating PMPMs, which was again demonstrated during treatment of wastewater containing cationic golden yellow. Furthermore, the adsorption kinetics of methyl violet by PMPMs was also studied. It was found that the adsorption capacity depended on the initial concentration of dyes, and the pseudo-second-order model was more suitable to describe adsorption kinetics of methyl violet than the pseudo-first-order model.