MOLECULAR-TRANSPORT OF BENZENE AND METHYL-SUBSTITUTED BENZENES INTO FILLED NATURAL-RUBBER SHEETS

Sorption and diffusion of benzene and methyl-substituted benzenes were investigated through natural rubber reinforced with four types of car bon black: superabrasion furnace, intermediate superabrasion furnace, high-abrasion furnace, and semireinforcing furnace. The rubber loaded with superabrasion furnace took the lowest amount of solvents among al l the samples. It was observed that the mechanism of transport deviate s from the normal Fickian trend with a decrease in particle size of th e fillers. The diffusion coefficients were determined considering the changes in thickness as well as the diameter of the natural rubber sam ples. From the temperature dependence of diffusivity, the activation e nergy for the diffusion process was computed. The sorption data were u sed to estimate the rubber-solvent interaction parameter, enthalpy, an d entropy of the sorption process. (C) 1996 John Wiley & Sons, Inc.