SynopsisThe penetration rate of chloroform (highly volatile solvent) in chloroprene rubber vulcanizate, based on different carbon black type and loading, has been studied. The results relevent to carbon black loading have shown an increase in the penetration rate with the increase in loading percentage. Other factors affecting the penetration rate, such as particle size and aggregate structures of carbon black, have shown some confusing results, such as the decrease in penetration rate with the increase of particle size and the decrease in penetration rate at a higher degree of equilibrium volume swelling. These results were attributed to the wrinkles formed at the surface of the rubber at these high equilibrium swellings.