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Polypropylene (PP) hybrid composites based on rice husk (RH) with different particle size and glass fiber (GF) with different length were prepared. The composites were subjected to mechanical and water immersion tests. From the results obtained, it was found that the mechanical properties of the hybrid composites were strongly dependent on the size of RH particle and length of GF. It could be further enhanced with the presence of coupling agent. In this study, two types of coupling agents, i.e., Epolene E-43 (E-43) and 3-(trimethoxysilyl)-propylmethacrylate (TPM), were employed. In general, E-43 imparted significant improvement in the mechanical properties. From the water immersion results, it was found that the hydrophobicity of the composites was increased with the presence of coupling agent.

In this study two commercial types of reinforced glass fibers were studied: chopped and 0/90 fiber glass composted with unsaturated polyester resin. The composites were prepared by hand lay-up method in three layers. The flexure properties were studied by using three-point bending test. The results showed that pure unsaturated polyester UPE is fractured when it reach the maximum point. Different behavior was shown for the fiber/polyester composite depending on the type of the fiber. The damage causes by the applied stress was appeared by photographs. In all samples the matrix cracking occur in the lower face of the specimen followed by fiber fracture due to the bending stress.

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Epoxidised rubber seed oil (ERSO) was successfully synthesized into non-isocyanate polyurethane via carboxylation method whereas peroxoformic acid was formed by in-situ reaction for epoxidation. The effects of temperature and ratio of hydrogen peroxide and formic acid to rubber seed oil carboxylation were studied. The optimum temperature for the epoxidation reaction was found at 50 °C to avoid ring opening reaction of epoxy whilst the optimum ratio of hydrogen peroxide and formic acid is equal molar of double bond: formic acid at 1:2 and 1:1, respectively. At a lower concentration of hydrogen peroxide and formic acid, the oxirane ring was stable due to the lower hydrolysis (oxirane cleavage) of an epoxide. The effect of using low content of formic acid tends to minimize unwanted epoxide ring opening to occur and make the epoxidation rate increased with increasing of oxirane number. Fourier transform infrared (FTIR) spectral displayed the presence of an epoxy functional group at 822 cm-1 and the disappearance of double bond peak at 3011 cm-1 corresponding to epoxidised oil and carbonyl group confirmed the epoxidation reaction had taken place. 1H-NMR was used to confirm the formation of carboxylate functionality after the reaction of epoxy at δ 4.83 and 4.61 ppm. In conclusion, ERSO has great potential to be used as a precursor in producing environmentally friendly non-isocyanate polyurethane.