Findings the proper high styrene resin/accelerator/antioxidant ratios to natural rubber/reclaimed rubber composites: Cure characteristics, mechanical properties and weathering resistance

This study presents the effects of varying ratios of high styrene rubber (HSR), carbon black (CB), N,N’-dibenzylthiuram disulfide (MBTS), and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) on the cure characteristics, mechanical properties, and aging stability of natural rubber (NR)/reclaim rubber (RR) composites. The addition of TMQ increased cure time and torque values but reduced tensile properties due to defects in the rubber matrix. Increasing HSR content reduced crosslink density, while higher MBTS concentrations improved crosslinking and reduced cure time. NR/RR composites with optimized ratios (10:60:3:0-2 and 10:60:4:0-2) exhibited the highest tensile strength and elongation at break. Weathering tests showed that UV exposure improved tensile strength and modulus, particularly with higher MBTS concentrations, enhancing chemical stability. These findings suggest that HSR, TMQ, CB, and MBTS ratios can optimize NR/RR composites for improved durability in harsh conditions for applying in the formulation of outdoor applications.