Influence of thermal ageing process on the crack propagation of rubber used for tire application

The present work studies the influence of thermal aging behaviour of rubber compounds based on natural rubber (NR), styrene butadiene rubber (SBR) and their blend NR/SBR 60/40 on dynamic-mechanical and fatigue crack growth properties. The thermal ageing at the temperatures 70 and 110 degrees C has been applied, which closely simulates the real service conditions of tires. Dynamic mechanical analysis (DMA) and fatigue crack growth (FCG) properties were characterised for the aged samples. The loss compliance J" has been determined as a parameter, which effectively is detecting the embrittlement or softening/hardening behaviour of the aged rubber. Finally, the FCG studies revealed that increase in aging temperature has deleterious effect on crack growth resistance as was reflected in all the aged materials