THE INFLUENCE OF SINGLE-CHAIN AND MULTI-CHAIN PROPERTIES ON THE MECHANICAL-BEHAVIOR OF CARBON-BLACK FILLED ELASTOMERS .1. DYNAMIC MECHANICAL-PROPERTIES

Wet skid resistance (WSR) and rolling resistance (RR) of several carbon black filled vulcanizates containing different rubbers in 100 phr were investigated in dependence of glass temperature, T(g), and plateau modulus, G(N)0, of the raw polymers. Furthermore, the influence of the amount of curing agent on WSR respectively RR was measured in some cases. It is shown that T(g) and G(N)0 give only trends, but there are no significant correlations concerning WSR and RR. The dependence of rolling resistance on the chemical crosslink density is more pronounced than it is the case for wet skid resistance. Based on the following facts, all test results can be explained in a first approximation: i) WSR of the vulcanizates depends on the global viscoelastic material behavior in the glass transition region. ii) RR is dominated by the molecular motions in the plateau zone of the dynamic storage modulus. By modification of the skid samples it can be demonstrated that the viscoelastic processes determining the wet skid behavior in the lab test take place in a surface layer the thickness of which seems to be less than 0,5 mm.