Biodegradable block copolymer as compatibilizer and blend component of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-based polyester blends

Abstract

Atactic poly(3-hydroxybutyrate) (PHB)-b-poly(ε-caprolactone) (PCL) diblock copolymer, a type of biodegradable block copolymer (BCP) was selected as compatibilizer for poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)/PCL immiscible blends. The additive effect of BCP on the morphologies and mechanical properties was dependent on the blend composition of PHBH/PCL. For 80/20 (w/w) PHBH/PCL blends, the incorporation of BCP did alter their mechanical properties by the increase in elongation at break with increasing BCP amount. However, the addition of BCP for 60/40 (w/w) PHBH/PCL blends were not greatly affected on their morphologies and mechanical properties. When BCP was used as one of binary blend components, the mechanical properties were significantly changed depending on the blend composition. PHBH/BCP blends also showed promising improvement in terms of mechanical performance. Presence of BCP in the ternary and binary blend systems decreased the enzymatic degradation rate by PHB depolymerase.