SOLUBILITY AND DIFFUSION-COEFFICIENT OF GASEOUS ETHYLENE AND ALPHA-OLEFIN IN ETHYLENE ALPHA-OLEFIN RANDOM COPOLYMERS

Solubility and diffusion coefficient of ethylene and alpha-olefin in random copolymers of ethylene/alpha-olefin were determined. Henry's constants from the sorption isotherm and diffusion coefficients of ethylene and propylene were found to be nearly independent of copolymer composition, while those of 1-butene exhibited a slight dependence on copolymer composition. The solubility of a mixture of the gaseous monomers was higher than that estimated from independent sorption using the respective Henry's constants of the pure gases. The mixing effect became more pronounced as the partial pressure of the more soluble gas in the gas phase increased.