Mechanical behaviour of agro-residue reinforced poly(3-hydroxybutyrate-co-3-hydroxyvalerate), (PHBV) green composites: A comparison with traditional polypropylene composites

Novel green composites were successfully fabricated by incorporating agro-residues as corn straw (CS), soy stalk (SS) and wheat straw (WS) into the bacterial polyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, by melt mixing technique. Effects of these biomass fibers on mechanical, thermal, and dynamic mechanical properties of PHBV were investigated. A comparative study of biomass fiber-reinforced polypropylene composite systems was performed. The tensile and storage modulus of PHBV was improved by maximum 256% and 308% with the reinforcement of 30 wt.% agricultural byproducts to it. For equal amounts of (30%) biomass fibers, tensile and flexural modulii of PHBV composites showed much higher values than corresponding PP composites. Alkali treatment of wheat straw fibers enhanced strain @ break and impact strength of PHBV composites by ∼35%, hardly increasing strength and modulus compared to their untreated counterparts. DMA studies indicated better interfacial interaction of PHBV with the biomass fibers than PP. Scanning electron microscopy (SEM), used to study the morphology of composites, also revealed similar outcomes.