A comparative study of gamma irradiation of poly(ethylene-co-vinyl acetate) and poly(ethylene-co-vinyl acetate)/carbon black mixture

In this comparative study, the effect of gamma rays on poly(ethylene-co- vinyl acetate) (EVA) and poly(ethylene-co-vinyl acetate)/carbon black mixture (EVA/CB) was investigated. EVA, containing 13% vinyl acetate (VA), and EVA/CB, containing 13% VA and 1% carbon black (CB), were irradiated with gamma rays at ambient conditions up to 400 kGy. Sol-gel analyses were made to determine the percentage gelation of both virgin and irradiated samples. FT-IR measurements were performed to follow the chemical changes, which took place in the samples during irradiation. Dynamic and isothermal thermogravimetry studies were performed for determination of the thermal stabilities of virgin and irradiated samples. Sol-gel analysis results showed that both EVA and EVA/CB have tendencies to form a gel under gamma irradiation. As a result of FT-IR measurements, some oxidation products were observed in EVA and EVA/CB upon gamma irradiation. Thermal analysis experiments exhibited that the overall thermal stabilities of EVA and EVA/CB do not change, whereas, the amount of volatile products, formed during gamma irradiation, increase with irradiation dose both in EVA and EVA/CB.