Reactive Extrusion of Biodegradable Poly(3-hydroxybutyrate-<i>co</i>-3-hyrdoxyvalerate) and Poly(butylene adipate-<i>co</i>-terephthalate) Blends: Toward a Toughening Approach

The brittleness of biobased and biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) remains a big hindrance to its broad application. Although blending with tougher biopolymers is one of the approaches to address this drawback, the improvement in the toughness of the blend is not usually satisfying, mainly due to the low compatibility of blend constituents. In this work, poly(butylene adipate-co-terephthalate) (PBAT), as a flexible biopolymer, was incorporated into the PHBV matrix in the presence of various contents of two reactive chemicals, a peroxide and a cross-linking agent, namely, triallyl isocyanurate. Mechanical analysis showed significant enhancement in impact resistance and deformability at some specific contents of reactive reagents, with the maximum improvement from 26.6 J/m and 7.9% in the neat blend to 91.3 J/m and 94.6% in the material including 0.15 parts per hundred (phr) of peroxide and 1 phr of cross-linking agent. The morphological analysis also revealed a significant decrease in the PBAT particle size by adding reactive reagents, implying the compatibilization effect of two reagents.