Radiation-induced graft polymerization of chitosan onto poly(3-hydroxybutyrate)

Chitosan is among the most studied biopolymers and offers important advantages, such as biodegradability, biocompatibility and nontoxicity. In this study, this polysaccharide was grafted onto poly(3-hydroxybutyrate) using the simultaneous gamma-irradiation-initiated polymerization method. The polyester was immersed in diverse solvents, which allowed the preparation of graft copolymers with different yields and crystallinities. A successful synthesis and the estimation of the degree of crystallinity were verified by spectroscopic and calorimetric techniques. The most suitable method was found to be the thermoanalytical approach because it displayed a linear relationship between the degree of crystallinity and the increasing degree of grafting. The results also indicated that the lowest degree of grafting was seen for acetic acid (14.27%), while the highest degree corresponded to ethyl acetate (32.11%). The mechanism of grafting was proposed on the basis of the experimental results.