硅烷接枝聚乙烯的催化机理与交联动力学研究

为了进一步探讨硅烷接枝聚乙烯水解交联反应机理及动力学,通过酸、碱和盐催化作用原理,说明了羧酸锡对交联反应的作用,用凝胶含量(G%)指标表征了交联反应程度,讨论了反应条件(温度、催化剂用量、水分扩散速度等)对该反应动力学的影响.结果表明:交联反应程度随催化剂浓度升高和环境湿度增大而增大;利用Arrhenius方程可表征该反应动力学的特征,并可求出交联反应的活化能(39.46 kJ/mol);提高水解温度,可加快水在聚乙烯中的扩散速度,因此,也加快了交联反应.硅烷接枝聚乙烯水解交联反应是关于催化剂和水分浓度的一级反应.

Study on catalytic mechanism and crosslinking kinetics of a silane grafting with polyethylenes

To study on catalytic mechanism and crosslinking kinetics of a silane grafting with polyethylenes,this work described an effect of tin carboxylate on the crosslinking,employing the acidic,basic and salt catalysis.A crosslinking conversion was characterized by gelation(G%).The influence of reaction conditions(such as temperature,amount of the catalyst,diffusion rate of water) on the kinetics was discussed.As a result,the crosslinking rate increased with an increase in the catalyst concentration and in the environment humidity.The kinetics was characterized by Arrhenius equation and the activate energy was solved(39.46 kJ/mol).The diffusion of water in polyethylene was accelerated with rising water temperature,and then the crosslinking rate was increased.The hydrolytic crosslinking of silane grafting with polyethylene was a kinetic first order reaction.