The Migration of Extender Oil in Natural and Synthetic Rubber. V. Dependence of Diffusion Rates on Oil Concentration and Elastomer Blend Ratios. The Locus of Oil in a Simulated Tire during Service

Publisher Website
Google Scholar
Abstract
Using carbon-14 labelled aromatic extender oil as a penetrant species, diffusion rates were measured in practical elastomeric compounds of high oil concentration, and in elastomer compounds based on blended polymers. These results, combined with earlier data, allow the calculation of the locus of oil during the service life of the rubber product. Increasing the concentration of oil increases the rate of diffusion of oil. Butyl rubber was the most sensitive to this effect, albeit the slowest in rate of migration, with a 2-fold increase in migration rate over the range of oil concentration of 2–27%, followed by polybutadiene, 1.53; natural rubber, 1.27; and ethylene-propylene-diene rubber, 1.26, and SBR, 1.00. Polymer blends display no synergism in their effect on diffusion; the diffusivity of oil in the blends was predicted exactly by the weighted average of polymer composition. Further studies of the effect of dynamic flexing indicated that, at constant temperature, static and dynamic conditions gave equal diffusivities. Calculations were made of the locus of the oil in a simulated tire section at 3000, 6000, 9000, and 24,000 miles. These agree very closely with experi mental results on a vulcanized, aged simulated tire segment.

This publication has 0 references indexed in Scilit: