CURE AND MECHANICAL BEHAVIOR OF RUBBER COMPOUNDS CONTAINING GROUND VULCANIZATES: PART III. TENSILE AND TEAR STRENGTH

A black-filled slyrene-butadiene rubber (SBR) vulcanizate was ambiently ground, then used as an additive to the original, uncured compound. Sheets of the resulting composite (matrix/ground rubber particulate) were cured, and tensile and trouser tear strength determined. The composite had reduced tensile strength, but enhanced tear strength relative to the original vulcanizate. The contrasting behavior is attributed to the effects of sulfur migration into the particulate rubber and differences in the responses of a tensile and a tear testpiece to discontinuities. Inbrief, ground rubber acts as a stress-raising flaw in tensile testing, while promoting crack tip blunting and stick-slip behavior in trouser tearing.