Enhancement of interfacial adhesion in immiscible polymer blend by using a graft copolymer synthesized from propargyl-terminated poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Abstract

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) is a biomass-derived polymer synthesized by the fermentation inside the bacteria, which has excellent flexibility and mechanical toughness. However, the industrial applications of PHBH have been limited because of its poor modulus of elasticity and tensile strength. For improving the mechanical characteristics of PHBH to eventually broaden its industrial applications, it was blended with poly(methyl methacrylate) (PMMA), a rigid polymer. Moreover, blending PHBH was also expected to increase the toughness of PMMA. Nevertheless, PHBH/PMMA blends lack interfacial adhesion due to low miscibility, thus restricting potential applications. This work focusses on enhancing the compatibility of PHBH/PMMA blend by developing a compatibilizer. The synthesis of PMMA-g-PHBH, a graft copolymer, was carried out using methyl methacrylate and vinyl-terminated PHBH derived from propargyl-terminated PHBH. The findings obtained from scanning electron microscopy and thermal analysis showed improvement in the miscibility of PHBH and PMMA upon the inclusion of PMMA-g-PHBH in the blend structure. The mechanical properties of the blends can also be tuned by controlling the weight fraction of PHBH/PMMA/PMMA-g-PHBH. This study proves that PMMA-g-PHBH acts as an effective compatibilizer for PHBH/PMMA blends.