Effect of Gamma Radiation on the Properties of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)/Poly(ε-Caprolactone) Blends

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(epsilon-caprolactone) (PCL) and a PHBV/PCL blend with a 75/25 composition (wt%) were processed by injection molding and then subjected to 50 and 100 kGy of gamma radiation. The crystallinity of pure PHBV and PCL and the PHBV/PCL blend was found to increase slightly after gamma radiation, suggesting that radiation in the doses studied here probably caused the scission of polymer chains. The slight increase in crystallinity sufficed to significantly augment the Young's modulus and ultimate tensile strength of the materials and to decrease their elongation at break. The shifts in the Tg of pure polymers in the PCL/PHBV blend suggest that a chemical interaction was favored by exposure to gamma radiation.