Hysteresis manifestation of graded rubber

Abstract

AbstractIn the present study, hysteresis loss in the cyclic stress–strain curves of graded styrene–butadiene rubber (SBR) was compared with that of homogenously crosslinked SBR. The graded SBR was prepared by vulcanization in a temperature gradient, which provided a gradient of crosslink density in the thickness direction of the sheet. The graded SBR had a higher hysteresis loss ratio than the homogenously crosslinked SBR, even though they had similar Young's moduli. The large energy loss must be attributed to the viscous response of the low‐crosslink‐density side of the rubber sheet. After the unloading process, the graded rubber exhibited a large instantaneous residual strain. However, its actual residual strain was small after waiting for a long time, indicating good rubber elasticity, which was attributed to the elastic response of the high‐crosslink‐density side of the rubber.