Circular deformation as a means of simultaneously evaluating the compressive and tensile strain in vulcanized rubber

The recovery behavior of vulcanized rubber composed of a chloroprene rubber (CR) and natural rubber (NR) blend was investigated using a circular deformation technique. A linear sample of vulcanized rubber was circularly deformed and thermally aged. The tensile and compressive strains, and stress distributions, in the circularly deformed state were evaluated using finite element analysis (FEA). The stress and strain varied uniformly across the thickness of the sample, and the degree of recovery increased with the measurement time after the removal of deformation and decreased by increasing the thermal aging time. Instantaneous recoveries were obtained by extrapolation of the degree of recovery as a function of aging time. The crosslink density in the compressed interior of the sample was greater than that of the elongated exterior component.