Trouser Tearing of a Model Natural Rubber Tire Belt Vulcanizate. Part 1: Effect of Rate of Tearing

Abstract

Abstract A model natural rubber tire belt vulcanizate (50 phr N330; 5 phr S; 0.75 phr DCBS accelerator) was torn using a trouser tear test piece that had legs 6 mm thick and an intended tear path about 0.8 mm thick. Tearing at 500 mm/min resulted in three distinct tear types. Two of the tear types gave high tearing forces, were stick—slip, and involved deep tearing into the legs (“chunk-out” and “knotty”). In the third, the tear remained in the thin path, alternated between legs (“sawtooth”), and was more-or-less steady. Cracking into the legs sometimes occurs and other times not. This variation appears to be inherent. It is attributed to variations in strain-induced crystallinity at high rates of strain. At a slower test rate of 5 mm/min, only knotty tearing was found. At 5 mm/min, there appears to be ample time for crystallites to develop well, and knotty tearing is always seen.