Preparation and properties of blends from poly(3‐hydroxybutyrate) with poly(vinyl acetate)‐modified starch

This research used the ceric ion to initiate the graft‐polymerization of vinyl acetate (VAc) to a soluble potato starch. Fourier transform infrared spectra confirmed the formation of starch graft copolymer. After 4 h of reaction at 50°C, total monomer conversion, grafting efficiency, and grafting ratio were measured as 91%, 12.5%, and 0.223, respectively. The synthesized PVAc‐modified starch was then blended with poly(3‐hydroxybutyrate) (PHB). Structures, thermal and mechanical properties of the prepared blends were examined. The results showed the PHB and PVAc‐modified starch were miscible in all compositions. In addition, thermal gravimetric analysis revealed that the addition of PVAc‐modified starch increased the thermal stability of the PHB component. Further evidence also showed that the addition of PVAc‐modified starch reduced the extent of decrease in molecular weight of PHB in a melt‐mixer. PHB/PVAc‐modified starch blends exhibit higher toughness than pure PHB because of increased compatibility and the leathery PVAc‐modified starch. POLYM. ENG. SCI., 2010.