The miscibility and biodegradability of poly(3-hydroxybutyrate) blends with poly(butylene succinate-co-butylene adipate) and poly(butylene succinate-co-ε-caprolactone)

The solid-phase structure and biodegradability were investigated for a series of binary blends of bacterial poly(3-hydroxybutyrate) with chemosynthetic poly(butylene succinate-co-butylene adipate) (PBSA) and poly(butylene succinate-co-ε-caprolactone) (PBSC) prepared via compression molding of solution cast films. By high-resolution solid-state 13C NMR and wide-angle X-ray diffractometer, the solid-state structures of both binary blend systems were studied. It was clearly demonstrated that these blends were immiscible systems on an observation scale of TH1 (several tens of nm) over the whole range of the blend composition. Further, it was suggested that the crystalline structure and degree of crystallinity of each component in these blends almost remained the same as those in the pure state. Enzymatic hydrolysis in the presence of lipase and environment degradation in river water were also studied for these blend systems. The biodegradability of aliphatic polyester is suggested to be controllable by blending.