Effects of solvents on the radiation grafting reaction of vinyl compounds on poly (3-hydroxybutyrate)

• PHB was indirectly grafted with PVA, by complete hydrolysis of grafted PVAc.
• The effect of solvents on the grafting, crystallinity and biodegradation was studied.
• The characterizations of the products were obtained by SEM, TGA, and DSC.

Vinyl Acetate was grafted onto poly (3-hydroxybutyrate) by the simultaneous gamma irradiation method using different types of solvents and in bulk (solvent free), at 10 kGy and 1.62 kGy/h dose and dose rate respectively. Subsequent complete hydrolysis allowed the conversion of grafted chains from poly (vinyl acetate) to poly (vinyl alcohol). The aim of this study is to determine the effect of solvent through the estimation of the dependence of the degree of grafting with the choice of solvent, the calculation of the degree of crystallinity, and to study the biodegradation of the products. The results showed a greater degree of grafting in bulk, while the more suitable solvent was hexane. Characterization of the grafted copolymer indicated that crystallinity percentage decreased by an increase in grafting, while the biodegradability was promoted by the increment in poly (vinyl alcohol) grafted.