The effect of scragging strain on the dynamic mechanical properties of filled rubber

A series of tests have been carried out on two example filled natural rubber (NR) and styrene-butadiene rubber (SBR) compounds in which the rubbers were scragged to a series of increasing shear strains and the effect of this on the dynamic properties at the lower strains were measured. After a long period, the tests were repeated to measure the recovery in the materials. It was found that increasing the scragging strain caused the rubber stiffness at lower strains to fall continuously, with no sign that it would reach a constant value and that while there was some recovery over time, it is not thought that the rubber would ever recover its initial stiffness.