Comparison between peroxide/coagent cross-linking systems and sulfur for producing tire treads from elastomeric compounds

Abstract

The aim of this work was to evaluate peroxide systems with and without coagents as cross-linking agents for rubber compounds in tires, which are usually prepared with sulfur. Natural rubber (NR) and styrene–butadiene rubber (SBR) formulations were prepared in open and closed mixers using an NR/SBR compound cured with sulfur as a reference. The physical properties (hardness, tensile strength, tearing, and abrasion) and dynamic mechanical behavior of the NR/SBR compounds cured with different cross-linking agents were evaluated. The NR/SBR compounds cured with only peroxide had poorer properties than did the vulcanized compound. On the other hand, the coagents were quite effective, and the NR/SBR compounds with BIS F40 + Retilink T40 (compound 10) or BIS F40 + T70A (compound 11) had properties similar to those of the reference compound. Compound 10 and the reference compound yielded similar tan δ values from dynamic mechanical analysis at 60 and 0°C, which are related to the rolling resistance and wet traction, respectively. The results demonstrate the possibility of using a peroxide/coagent NR/SBR compound instead of a sulfur-cured compound for tire tread applications without the loss of desirable properties and with lower costs and processing times.