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The interfacial shear strength (IFSS) between a bamboo fiber bundle and maleic anhydride polypropylene (MAPP) was examined for various kinds of surface treatments in conjunction with ultrasonic washing. Bamboo fiber bundles were extracted from Chinese bamboo by either mechanical scratching or steam explosion. The effect of fiber bundle diameter on IFSS was measured by using the micro-droplet test. The test results showed that higher IFSS was observed for bundles having smaller diameter. Isocyanate silane treatment improved IFSS in the case of raw bamboo fibers while it was less effective to improve IFSS for steam exploded fibers. The highest tensile strength of bamboo fiber reinforced polypropylene was obtained when steam exploded bamboo fibers were used as the reinforcement.

In this study, the simultaneous effects of both silanized coal fly ash (S‐CFA) and nano/micro glass fiber (nGF) on fracture toughness and mechanical properties of vinyl ester (VE) resin filled with carbon fiber‐based composite materials were investigated. The CFA was treated with (3‐trimethoxysilyl) propyl methacrylate to introduce the methacryloxy groups into the surface of CFA, and was confirmed by using FTIR technique. The nGF and S‐CFA with different weight ratios were well mixed with VE resin by using of high‐speed mechanical stirrer, and ultrasonic technique before using as matrices for fabrication of carbon fiber‐based composite materials via sheet molding compound (SMC) method and hot curing processing. Many characteristics of both cured VE resin composites and carbon fiber‐based composite were examined such as mechanical properties, fracture toughness, and morphology. The results showed that by adding of both 0.1 wt% nGF and 1 wt% S‐CFA into VE resin the tensile strength, tensile modulus, flexural strength, KIC, impact strength as well as the Mode I interlaminar fracture toughness (GIC) of VE composites and carbon fiber based composites get optimum values and increased about 61.39%; 39.83%; 36.21%; 103.1%; 81.79%; 48.61%, respectively when compared with pristine materials. POLYM. ENG. SCI., 59:584–591, 2019. © 2018 Society of Plastics Engineers

The poly(butylene succinate) (PBS) biodegradable composites reinforced with short coir fibres were fabricated by compression molding method. Effect of different fibre contents varying from 10 to 50 wt% on the mechanical and thermal properties of coir/PBS composites have been studied in terms of tensile and flexural properties, thermal stability, thermal expansion, dynamic mechanical properties, and microscopic observations. Tensile and flexural moduli of the composites were improved with the increase of fibre content up to 50 wt%. The results of thermogravimetric analysis showed that thermal stability of coir/PBS biodegradable composites is remarkably to be intermediate between the PBS resin and coir fibre depending on the fibre content. The thermomechanical stability of PBS resin is significantly improved by the addition of reinforcing coir fibres into the composite matrix. Dynamic mechanical analysis results also confirmed that the storage modulus of the composites was increased with increase in the loading of coir fibre, showing the stress transfers from the matrix to the fibre. The greatest value of storage modulus and lowest coefficient of thermal expansion obtained at 50 wt% fibre content in the present study. The fracture surface morphology of the composite specimens observed by scanning electron microscope (SEM) showed the weak bonding between untreated coir fibre and PBS matrix.

The dynamic mechanical behavior of modified deproteinized natural rubber (DPNR) prepared by graft copolymerization with various styrene contents was investigated at a wide range of temperatures. Graft copolymerization of styrene onto DPNR was performed in latex stage using tert-butyl hydroperoxide (TBHPO) and tetraethylene pentamine (TEPA) as redox initiator. The mechanical properties were measured by tensile test and the viscoelastic properties of the resulting graft copolymers at wide range of temperature and frequency were investigated. It was found that the tensile strength depends on the grafted polystyrene; meanwhile the dynamic mechanical properties of the modification of DPNR meaningfully improved with the increasing of both homopolystyrene and grafted polystyrene compared to DPNR. The dynamic mechanical properties of graft copolymer over a large time scale were studied by constructing the master curves. The value of bT has been used to prove the energetic and entropic elasticity of the graft copolymer.