Sorption of volatile compounds into electron beam irradiated EVA film in the vapour phase

In order to investigate the sorption of volatile compounds by electron beam irradiated ethylene/vinyl acetate copolymer (EVA) films, permeation measurements in the vapour phase were carried out. The diffusion coefficients of octane, ethyl hexanoate, octanal, octan‐1‐ol and d‐limonene increased with an increase in the irradiation dose. The sorption of all volatile compounds in this study was depressed in electron beam irradiated film: the decreases in solubility coefficients for 20 Mrad EVA film were 15% for octane and ethyl hexanoate, 45% for octan‐1‐ol and octanal, and 50% for d‐limonene. The enthalpy change in sorption (ΔH) of ethyl hexanoate was −13·4 kJ mol⁻¹ for 50 g kg⁻¹ EVA film at a dose of 20 Mrad compared with −27·6 kJ mol⁻¹ for the unirradiated one. In a homologous series of aliphatic alcohols, sorption was significantly depressed with increasing carbon chain length. Judging from both heat‐seal strength and sorption behaviours, the most appropriate irradiation dose for the practical usage of irradiated EVA film was less than 15, 10 and 5 Mrad for 50, 95 and 150 g kg⁻¹ EVA film, respectively.