Chain Scissions of Rubber Molecules by a Tensile Force in Filled Rubber Systems

Effects of interfacial interactions between rubber matrix and filler surface on the structural changes of rubber matrix upon a tensile deformation of filled styrene-butadiene rubber (SBR) vulcanizates were studied by ESR and pulsed NMR. The interfacial interactions were controlled by using several kinds of surface modified silicas and carbon blacks. For silica filled systems, the degree of chain scission during tensile deformation of the samples could be evaluated from ESR results. Information on the structural changes of rubber matrix upon a tensile deformation for both carbon black filled and silica filled SBR vulcanizates could be obtained from the results of pulsed NMR. The combination of ESR and NMR results revealed that the degree of chain scission was dependent on the strength of interfacial bondings between filler and rubber molecules and the chain scissions are suggested to occur in the interfacial regions between rubber molecules and fillers.