Heat build-up characterization under realistic load
A newly developed test equipment to characterize in-situ the heat build-up (HBU) process inside of rubber sample is introduced and is labeled Heat build-up Analyzer (HBUA). It uses unique multiaxial measuring capabilities such as dynamic alteration torque and multi-planar bending vs. programmable load cycle. Therefore, the appliance controls the user defined loading conditions in a wide range of combinations which may occur and thus simulate the realistic load applied on rubber products in field. In this study, the HBU is measured and correlated with dynamic mechanical analyses (DMA) for basic carbon black (CB) filled rubber compounds based on pure natural rubber (NR), styrene butadiene rubber (SBR) and butadiene rubber (BR). The results show very clear correlation between the HBU and DMA data, whereas SBR generated the highest HBU, respective tanδ, and BR generated the lowest HBU, respective tanδ. Finally, the HBU in dependence on no. of loading cycles inside and on the surface of loaded rubber sample is discussed. Moreover, the HBU data for an exemplary real rubber compound used for tire tread application in agricultural tire are compared with the data observed for model rubber compounds. Significantly higher HBU was determined for real rubber compared to model rubber compound. The equipment and data provide fresh insights into the widespread durability success of rubber product compounds.