عنوان مقاله [English]
Hypothis: Rubber powder with a very fine particle size, rough surface and very low impurities can be prepared by water jet technology. The use of this powder as a suitable additive in tyre compounds is very important from economic and environmental viewpoints.
Methods: Morphology of the water jet powder was investigated using SEM. The rubber powder was added to a SBR/BR-based tyre tread formulation and the curing behavior and mechanical properties of the resultant product were determined. A full factorial experimental design was also conducted to study simultaneously the effects of rubber powder, sulfur and carbon black levels on the curing and mechanical properties of tyre tread formulation. Furthermore, the modification effect of Vestenamer additive and curing agent on the formulation properties was investigated. When using design of experiments, for each property the regression models with linear and binary interaction terms on the basis of three variables were successfully developed and statistically validated.
Findings: The rubber powder showed a lowering effect on tensile properties, which was attributed to reduced crosslink density due to the sulfur migration from the rubber matrix to the powder phase. A small, but statistically significant negative effect on the aging, abrasion and resilience properties of rubber compound was also observed, However, the tear resistance and de Mattia crack growth were improved with increasing rubber powder content, that could be attributed to the lesser effect of rubber powder on the compound modulus. It was shown that with some increase in the curing agent, sulfur and accelerator dosage, it was possible to compensate for the tensile properties to some extent and for the abrasion, resilience and aging properties completely, whereas others remained relatively unchanged. It was also shown that except for abrasion, the Vestenamer processing aid had little improving effect in the presence of rubber powder.