Effect of curing system on the mechanical properties and heat aging resistance of natural rubber/tire tread reclaimed rubber blends

This research aims to elucidate the effect of a sulfur vulcanization system, i.e. conventional vulcanization (CV) and efficient vulcanization (EV) on the mechanical properties and heat aging resistance of natural rubber (NR)/tire tread reclaimed rubber (RR) blends. The reclaimed rubber content in each system was varied from 10 to 50 phr. The mechanical properties such as tensile properties, tear strength, and abrasion resistance of the vulcanizates were determined. The results reveal that the blends in both curing systems show an increase in their hardness and modulus with increasing RR content while other mechanical properties are adversely affected. However, the properties of the blends are still suitable for some applications. In addition, most mechanical properties, except for the tensile retention, of the CV vulcanizates are generally higher than those of the EV vulcanizates. It also appears that tensile strength and tear strength of both CV and EV vulcanizates become comparable when RR content is high.