Control of biodegradability of poly(3-hydroxybutyric acid) film with grafting acrylic acid and thermal remolding

Wada, Yuki; Mitomo, Hiroshi*; Kasuya, Kenichi*; Nagasawa, Naotsugu; Seko, Noriaki; Katakai, Akio; Tamada, Masao

Radiation-induced graft polymerization of acrylic acid (AAc) on the surface of poly(3-hydroxybutyric acid) (PHB) film was carried out by applying pre-irradiation techniques. The PHB films grafted with AAc (PHB-g-AAc) possessed a degree of grafting higher than 5% have completely lost the enzymatic degradability. The enzymatic degradability of the grafted film was recovered by remolding. And the highest enzymatic degradation rate was observed to grafted films with AAc 10% of degree. Difference of enzymatic degradability of PHB-g-AAc film was caused by decrement of amount of enzyme contact and decrement of crystallinity of PHB by remolding.