有机硅建筑密封剂老化机理研究

Study on Ageing Mechanism of Structural Silicone Sealant

本文探讨了有机硅建筑密封剂潮气固化和降解的机理，并根据理想弹性体概念和理想弹性方程及Ｍａｘｗｅｌ模型建立了有机硅建筑密封剂在潮气中曝露时交联和降解的动力学模型。通过实验数据求得了动力学方程。结果表明，有机硅建筑密封剂在潮气中的性能变化呈现两个不可逆的简单的一级反应，即交联反应和降解反应，这两个反应的速度常数分别为ｋ１＝０．０２２４（１／天）和ｋ２＝０．０２７（１／天）。本方程的建立，为有机硅建筑密封剂实际应用中寿命的预测有重要借鉴意义。

the crosslinking and degradation mechanism of structural silicone sealants exposed to moisture have been investigated in this paper.On the basis of ideal elastomer concept and ideal elasticity equation and Maxwell model,the kinetic model of cross-linking and degradaion of silicone sealant exposed to moisture has been developed,and the chemical kinetic equation has been obtained.The results showed that the mechanism of reactions of silicone sealants in moisture is a simple series of two irreversible reactions,and their reaction rate constants k l and k 2 are 0 224/day and 0 027/day.