NR硫化返原过程的动力学研究

黄琛　 范汝良　 张勇　 张隐西　

摘　要：采用依据NR硫黄硫化返原机理建立起来的硫化返原动力学模型，对普通硫黄硫化体系和半有效硫化体系的NR在不同温度下的硫化曲线进行了计算机非线性拟合，从而求出了各步反应的速率常数，并进一步得到多硫键、双硫键和单硫键密度之和及交联密度随硫化时间变化的函数关系。结果表明：不同温度下两种体系采用该模型得到的模拟曲线与实际数据相吻合，求出的同一体系速率常数与硫化温度的关系符合Arrhenius方程。两种体系多硫键的裂解活化能都大于脱硫活化能，可解释随温度升高硫化返原程度增大的原因。
关键词：NR；硫化返原；硫化动力学；非线性拟合
分类号：TQ330.1⁺3；TQ332　文献标识码：A
文章编号：1000-890X(2000)04-0195-06

Kinetics of reversion process in NR vulcanization

HUANG Chen ,FAN Ru-liang ,ZHANG Yong ,ZHANG Yin-xi
(Shanghai Jiaotong University, Shanghai 200240)

Abstract：The computer-aided nonlinear fitting for the curing curves of NR compounds in sulfur vulcanization and semi-efficient vulcanization at different temperatures was made by using the model for kinetics of vulcanization reversion based on the reversion mechanism of sulfur cured NR vulcanizate to obtain the velocity constants in various reaction steps, the sum of single sulfide bonds, double sulfide bonds and polysulfide bonds, and the crosslinking density as a function of the curing time. The results showed that the simulated curves of two curing systems at different temperatures were fitted to the measured data, and the obtained relationship between the velocity constant and the curing temperature of the same system was in accordance with the Arrhenius equation. The reversion increased as the temperature rase, which could be explained by the fact that the activating energies of the polysulfide bond cracking for both systems were greater than those of the devulcanization.
Keywords：NR; reversion; vulcanization kinetics; nonlinear fitting

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收稿日期：1999-10-12