ABSTRACT
Haake internal mixer was used to incorporate paddy straw powder (PSP) into poly(3-hydroxyl butyrate-co-3 hydroxyvalerate) (PHBV). The effects of PSP content (5–20 wt%) on thermal and mechanical properties of the biocomposites were investigated. It was shown that the values of tensile strength and elongation at break (EB) were found to be decreased with an increase in PSP content due to the poor interfacial bonding between PSP and PHBV. Modulus elasticity was increased by increasing the PSP content. Thermogravimetric analysis (TGA) demonstrated that thermal stability of PHBV/PSP biocomposites is enhanced by PSP reinforcement. Biodegradability of PHBV–paddy straw biocomposites was evaluated by composting the biocomposite samples into the soil. Different techniques, including mechanical tests and scanning electron microscopy (SEM), were used in order to obtain a view of degradation occurring during the soil burial of the biocomposites. Results of the mechanical tests show that an increasing content of PSP in biocomposites decreases the tensile strength and EB, but increases the modulus of elasticity after exposure of 6 months. SEM on surfaces after soil burial shows that the filler is poorly wetted by the matrix. This explains the reduction in tensile strength and EB after soil burial.
