Cyclic volume changes in rubber

The present paper deals with the volume variation in filled crystallizable natural (F-NR) and uncrystallizable styrene-butadiene (F-SBR) rubbers subjected to cyclic loadings. During their deformation, such materials exhibit volume variation induced by the cavitation phenomenon and the decohesion between particles and the rubber matrix. In this study, we propose to measure this volume variation over the first mechanical cycles by an original full-field measurement technique. First, results show that in both filled compounds no residual volume change is observed. Moreover, after the first cycle, the response of both compounds is stabilized in terms of volume variation. However, a hysteresis loop is observed only for the first cycle in F-SBR whereas it is observed for each cycle in F-NR. Finally, the measurement method allow us to highlight the influence of stress-induced crystallization on the volume variation.