天然橡胶/硫黄/N-叔丁基-2-苯并噻唑次磺酰胺体系硫化反应动力学参数的拟合

Fitting of cure reaction kinetics parameters based on natural rubber/sulfur/N-tert-butyl-benzothiazole-2-sulfenamide

以N-叔丁基-2-苯并噻唑次磺酰胺为促进剂,通过橡胶加工分析仪测试了天然橡胶硫黄硫化体系的硫化曲线,用硫化反应动力学模型和Origin 6.0软件对诱导期后的硫化曲线进行非线性拟合,计算了该模型的有关动力学参数,探讨了硫黄用量和硫化温度对参数的影响。结果表明,在实验范围内,拟合的硫化曲线与实际的硫化曲线相吻合;在相同硫化温度下,硫化先驱体形成交联键的反应活性随着硫链长度的增加有所下降,而交联键长度的增加使其降解的速率常数也增大;随着硫黄用量的增加,硫化活性中间体形成交联键的趋势下降,生成副产物的几率增加,总的硫黄利用率下降;在相同硫黄用量下,交联键的分解反应对温度的依赖性比硫化先驱体分解产生交联中间体的反应更强。

The cure curves of natural rubber were tested by rubber processing analyzer with sulfur as curing agent, and N-tert-butyl-benzothiazole-2-sulfe-namide as accelerator. The cure curves of curing and overcure periods were then non-linear fitted by a cure reaction kinetics model and Origin 6.0 software and the kinetic parameters were calculated. Effect of sulfur dosage and cure temperature on the parameters was explored. The results showed that the simulated curves fitted well with the experimental curves. Rate constant for formation of activated crosslinking precursors decreased with increasing sulfur chain, while rate constant for crosslink degradation in-creased with extending crosslinkage under the same cure temperature. The tendency for formation of crosslinkage from activated intermediate decreased with the increasing sulfur dosage, the probability of generating by-product increased, and the sulfur efficiency decreased. The crosslinkage decomposition reaction had a stronger dependence of cure temperature than that of precursor decomposited to interme-diate.