Mechanical properties and structure of injection molded poly(hydroxybutyrate‐co‐hydroxyvalerate)/poly(butylene adipate‐co‐terephthalate) (PHBV/PBAT) blends

Abstract Blending poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) and poly(butylene adipate‐co‐ terephthalate) (PBAT) presents an effective approach to fabricate fully biodegradable polymer blends with tailored mechanical properties. This study investigated the composition on the mechanical properties and structure of PHBV/PBAT blend. The remarkable enhancement in elongation of the PHBV/PBAT blends was shown due to the ductile PBAT. The fracture behavior of the PHBV/PBAT specimens transited from brittle to ductile with the increase of the PBAT in the blends. Two different phases as a co‐continuous microstructure with a large interpenetrating structure indicate immiscibility between PHBV and PBAT in the PHBV/PBAT (50:50) specimen. The miscibility, intermolecular interaction, and mechanical properties of PHBV/PBAT blends were also investigated by molecular dynamics simulation. The results showed the immiscibility of PHBV and PBAT. The degradation temperature increased from 277 to 356°C with the increase of PBAT content in the PHBV/PBAT blend. Whereas the crystallinity ability of the PHBV component in the blend was confined by the PBAT phase, leading to a decrease in the overall crystallinity of PHBV.