SORPTION AND DIFFUSION OF ALDEHYDES AND KETONES INTO ELASTOMERS

The results of the sorption and diffusion of aldehydes and ketones int o structurally different elastomers such as ethylene propylene diene t erpolymer, styrene butadiene rubber, nitrile butadiene rubber, neopren e and natural rubber are described in the temperature interval of 25-6 0-degrees-C. From these data, the Arrhenius parameters for the process es of diffusion and permeation are determined. The activation paramete rs for the diffusion of ketones range from 10.29 to 49.62 kJ/mol and f or aldehydes, from 13.18 to 50.42 kJ/mol; these values fall in the ran ge expected for rubbery polymers well above their glass transition tem peratures. Transport data are affected by the nature of the interactin g solvent molecule rather than its size and also by the structural var iations of the elastomers. For all the solvents, the polymers remained intact; however, natural rubber in the presence of benzaldehyde showe d degradative reactions at higher temperatures. Volumetric expansions of the elastomers have been measured from the dimensional response in the presence of aggressive solvents.