Wet Skid Properties of Filled Rubbers and the Rubber—Glass Transition

The physical relationships between wet skid resistance of filled rubber compounds and the dynamics of the corresponding bulk polymers in the rubber—glass transition zone are investigated. We show how wet grip data and their ratings correlate with dynamic glass transition temperatures in the N(uclear)M(agnetic)R(esonance) time scale for the spin—spin relaxation time T2 that characterizes the relaxation of transverse magnetization. The corresponding frequency is independent of the Larmor frequency of the NMR experiment. The amount of the frequency is located in the frequency region of the glass—rubber transition and depends on the microstructure of the used polymers. Finally, some molecular aspects of the network dynamics in the transition zone are considered. Damping curves of different rubbers can be predicted using the bead-spring-model of Kloczkowski, Mark and Frisch (KMF), considered as an extented Rouse-model of an entanglement network with tree-like connectivity and a certain number of subchains.