Effect of Solvents on Gamma Radiation-Induced Graft Copolymerization of Vinyl Acetate onto Poly(3-hydroxybutyrate)

The effect of different solvents on the radiation-induced graft copolymerization of vinyl acetate onto poly(3-hydroxybutyrate) was studied. Structures of copolymers were determined with the techniques of thermogravimetric analysis and differential scanning calorimetry. From the thermal analysis results, it was found that the more favorable solvent to be used in the graft reaction is hexane. However, a much higher grafting degree can be achieved in bulk. The thermodynamic parameter obtained varied, showing that the enthalpy of melting and crystallization temperature of graft copolymers decreased with increasing grafting degree, which implies changes in the crystallization behavior and decrease in the material cristallinity. Further hydrolysis of the higher grafting degree graft copolymer was also studied.