硅烷接枝聚乙烯的催化机理与交联动力学研究

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

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.

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 re- suit, 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 then the crosslinking rate was increased. kinetic first order reaction. in polyethylene was accelerated with rising water temperature, and The hydrolytic crosslinking of silane grafting with polyethylene was a kinetic first order reaction.