Abstract: Epoxy/amine-coated polyester triangular bar composites were fabricated and exposed to 5 wt% hydrochloric acid (HCl) solution at 40 °C. The weight loss characteristics of pre-exposed composites in heated air at 40 °C under forced convection were studied as function of size, spacing, alignment, and orientation of triangular bars. The diffusion coefficient of composites during desorption increases when the bars are oriented flat and are aligned in parallel. The same result is observed when the size of triangular bars is increased, and when spacing between bars is decreased. These results are attributed to the presence of epoxy/polyester interphase regions, which are more accessible when the triangular bars are oriented flat and aligned parallel, have larger size, and have smaller spacing. These interphase regions are preferred conduits of water during desorption of composites. The diffusion coefficients of composites being higher than the values of epoxy and polyester resins further confirm the effect of interphase regions. Among the factors, orientation of triangular bars has the highest influence on the desorption behavior of epoxy composites.
Abstract: Pore closure behavior in sintered Al-4Fe3C and Al-4Fe3C-2Cu composite preforms were studied under cold and hot deformation conditions. Preforms of 0.2 aspect ratios with 85±1% initial density were prepared through compaction operation using 1 MN hydraulic press. For hot deformation, directly as sintered preforms are subjected to swaging operation to different strain rate. Preforms that are allowed to cool it to room temperature within the furnace after sintering process are subjected to cold upsetting till visible cracks appear on diametrical surface. The comparative analysis on pore closure against stress, strain, Poisson’s ratio and the stress formability index are performed.
Abstract: In this research, the alkaline treated and untreated sugarcane bagasse was used as reinforcement with unsaturated polyester to make composites. The composites were made with 0 to 20 weight percentage of fibers using compression molding. Acoustical, dielectrical and mechanical properties of the composites were studied according to the American Society for Testing Materials (ASTM) standards. The result shows that the composites with higher sugarcane bagasse loading show higher acoustical and dielectrical properties. The composites tensile strength increased up to 10wt% of fiber loading and then starts decreasing eventually. Tensile strength and sound absorption coefficients of alkali treated fiber composites shown slightly better results than untreated fiber composites. The dielectric constant of treated fiber composites were lower compared with untreated fiber composites.
Abstract: The development of bio-composites as biodegradable and renewable materials for sustainable technology are advantageous in creating a green and healthy environment. However, the application of natural fiber as a bio-composite material have been found to be restricted especially as it has lower thermal resistance in comparison to synthetic fiber. Therefore, the objective of this study is to investigate the influence of fiber orientations on the tensile properties at various tensile temperatures for unidirectional kenaf polypropylene (PP) composite. Samples were prepared by hot pressing process. In this study, kenaf long fibers that are produced from water retting process is use as a reinforcement agent while PP as a polymer in the composite fabrication. A tensile test was carried out at different temperatures (30°C, 60°C, 90°C, 120°C) for various orientations (0°, 45° and 90°). It was found that an increase of temperature will reduce the modulus and tensile strength where the highest reduction occurred between 60°C to 120°C and most significantly on the orientation of 45° and 90°, which is lower than pure PP. This concludes that the application of kenaf PP composite is optimum between room temperature with a cut-off temperature at 60°C.
Abstract: Carbon fibres and Kevlar fibres are among the commonly used fibres in the composite industry. As carbon fibres usually known for its superior strength, its low impact resistance limited its application in the industry. However, further research found that combining the high strength fibres with more ductile fibres like Kevlar could improve the material’s impact resistance. This hybrid effect was also found to be most effective by using intra-ply woven hybrid fibres in the composite. In this work, hybrid composite material was fabricated by using woven carbon-Kevlar cloths with epoxy matrix and the mechanical properties are determined at 0 ̊, 45 ̊ and 90 ̊. The hybrid composite material was found to have highest tensile strength at 0 ̊ (carbon) direction. As the material’s strength and tensile behaviour are different at every fibre types, the selection of fibre direction of the woven cloth in loading is an important criteria in any applications.
Abstract: The effect of replacing carbon black (CB) with surfactant-modified natural feldspar (SMNF) on hardness and tensile properties of natural rubber (NR) composites was studied using a simplex-lattice mixture design of experiment. SMNF was produced by treating natural feldspar (NF) with coconut diethanolamine (CDEA) and glycerol monostearate (GMS). Complete replacement of CB with SMNF based from CDEA or GMS decreased Shore A hardness and tensile stress at all elongations. NR composites reinforced with SMNF based from GMS exhibited higher mechanical properties than from CDEA which is attributed to the higher hydrophobicity factor of GMS. CDEA may also have aggregated on the surface of NF, resulting to poor filler dispersion and ineffective stress transfer.
Abstract: Natural zeolite, an abundant clay with porous solids based on silica, is modified with amine salt and surfactant, and incorporated as filler for polyester to produce modified zeolite/polyester (MZP) composite. A general factorial design of experiment is implemented with two factors (type of amine salt and type of surfactant) varied at three levels each. The amine salts are tetra- (TDA), hexa-, and octadecyl dimethylamine chloride while surfactants are stearic acid (SA), glycerol monostearate, and cocamide diethanolamine (CDEA). Water sorption and flexural testing are performed on MZPs. Results show that natural zeolite treated with SA exhibits improved hydrophobicity of MZPs, resulting to lower water uptake as compared to untreated natural zeolite. However, water sorption in MZPs is higher than in pure polyester due to difference in hydrophobicity. Flexural modulus of MZP is highest using TDA + CDEA due to enhanced filler-to-matrix compatibility. Meanwhile, break stress is highest for untreated zeolite filler due to the high stress resistance of rigid natural zeolite. Analysis of variance shows water sorption to be significantly affected by the type of surfactant, while break stress is significantly higher using amine salt with shorter chain length.
Abstract: This research was focused on the study of the synthesis process, and the physical and mechanical properties, of the composite material prepared from Poly(vinyl chloride) (PVC) and natural fiber extracted from reed, scientific namely Cyperus corymbosus Rotth, leading to the development of a new type of low cost material for the furniture function. Reed is chosen to be a source of natural fiber due to its ease of finding and ease of growth along water reservoir which can provide a cheap material for composite production. In the study, the samples were divided into four groups based on the addition of reed powder loading, ranged from a weight ratio of 0%, 20, 40 to 50%, respectively. The composite materials were pre-mixed, using white oil as coupling agent, by the single screw extruder, and the wood plastic was produced by compression molding method. The flat plate panels were tested by several standard techniques, including impact testing, bending testing and tensile testing. Morphology of the fracture surfaces and the dispersion of filler particles were observed by using scanning electron microscopy (SEM). The testing measurement revealed the decreasing of impact strength, tensile strength and flexural strength in all WPCs in comparison with pure PVC. This negative effect may be ascribed to the poor compatibility between the fibers and polymer matrix.
Abstract: The rising concern towards environmental issue underscores the “greenproducts” based on natural resources for a wide range of applications. Theseefforts include white rice husk ash (WRHA) considering as an alternative rawmaterial for lignocellulosic filler in green composite. We present the propertiesevaluation of composite WRHA dispersing into polyvinyl-chloride (PVC) with di-isononyl-phthalate(DINP) as compatibilizing agent by compression molding method. The XRD analysisshows typical main peak of silica crystalline, the strengthening materials asreinforcement within the composite structure. The SEM demonstrated that WRHAfillers were well embedded in PVC matrix and better adhesion occurred between themand the matrix. Thus, the adhesion between the reinforcing fiber and the matrixplays an important role in the mechanical properties of the materials. The positiveachievement for fire resistance and its mechanism were specially discussed forceiling board in/outdoor environment applications.