Improving thermal oxidative aging resistance and anti-reversion property of natural rubber by adding a crosslinking agent

摘要

The reversion during the curing and the poor thermal oxidative aging resistance of natural rubber are two main problems for its use as a tire tread. To solve the problems, a crosslinking agent, 1,6-bis(N,N '-dibenzyl thiocarbamoyl dithio)-hexane (DBTH), is added into natural rubber/carbon black composites. DBTH can increase the crosslink density, improve the mechanical properties and thermal oxidative aging resistance of the composites. The composites with DBTH can maintain good wet-skid resistance after thermal oxidative aging. When 0.2 phr DBTH is used to substitute 0.1 phr sulfur and 0.1 phr accelerator in a natural rubber/carbon black composite, the reversion during the curing is reduced and the DIN abrasion decreases by 6, while the modulus and hardness of the composite keep close to the original. Besides, after thermal oxidative aging at 100 degrees C for 48 h, the rate of change of stress at 300 strain of the composite decreases by 27 with the substitution of DBTH.