DIFFUSION AND TRANSPORT OF AROMATIC-HYDROCARBONS THROUGH NATURAL-RUBBER

The swelling of crosslinked natural rubber in aromatic hydrocarbons wa s investigated. Natural rubber was vulcanized by four vulcanizing syst ems, viz. conventional, efficient, dicumyl peroxide, and a mixture con sisting of sulfur and dicumyl peroxide. The peroxide-crosslinked syste m showed the lowest solvent uptake. The effect of different fillers on the swelling nature of crosslinked natural rubber was studied using c arbon black and silica fillers. The silica-filled sample took up highe r amounts of solvents than carbon-filled sample. The dependence of the diffusion coefficient on crosslinking system, filler, temperature, et c., was also studied. The solvent-polymer interaction parameter was ca lculated from the diffusion data.