Effect of gamma irradiation on the microstructure and morphology of polyethylene oxide and polyvinyl alcohol blends

Abstract

Thin films of a blend of 90, 75, 50 (wt/wt%) percentage of polyethylene oxide and polyvinyl alcohol were synthesized and irradiated with 5, 25, 50, 100 and 200 kGy. The presence of PVA leads to diffusion controlled mechanism where it decreases the crystallinity of PEO as restricted crystallization occurs.Low doses of 5 kGy cause crosslinking of the blends and increase the thermal stability. Higher doses up to 100 kGy cause the PEO crystallite boundaries to be erased and to blur spherulites structure; it also leads to an increase in the crystallinity. Higher doses of 200 kGy cause an increase in the hydrogen bonding where the material is more crystalline in structure and broken down which made more segments available for the hydrogen bonding. Degradation and oxidation of the blends due to the presence of free radicals in the polymer irradiated in air is noticed for blends with very high doses. Never the less, PVA in these blends protects the PEO composite from the effect of radiation.