聚酰亚胺薄膜表面水解动力学研究

Kinetics of Alkaline Hydrolysis of a Polyimide Surface

利用FT-IR测定了NaOH溶液处理聚酰亚胺薄膜表面水解过程。结果表明,聚酰亚胺在NaOH溶液中形成带有钠离子的高聚物,经盐酸溶液酸化,转变成聚酰胺酸;在水解初始阶段,聚酰亚胺薄膜表面完全与NaOH溶液充分接触,水解反应较快,随着反应时间的延长,聚酰亚胺薄膜表面附着一层聚酰胺酸,反应较慢;水解过程分为初期快速阶段和后期慢速阶段;采用两步、一级反应动力学模型研究薄膜水解程度并得出相关的动力学参数。

The alkaline hydrolysis of a polyimide（PMDA-ODA） film was investigated by FTIR. Polyamate（the natrium salt of polyamic acid） was formed as polyimide was reacted with NaOH, which was subsequently protonated using hydrochloric acid to get corresponding polyamic acid. At the beginning of hydrolysis, the polyimide film surface has sufficient contact with alkaline solutions and the reaction rate is comparatively fast; when the polyimide film surface is attached with a layer of polyamic acid, the rate becomes slow. The alkaline hydrolysis includes two steps of different reaction rates, a fast step and the following slow one. A two-step first order reaction kinetics model was applied to the alkaline hydrolysis, and the relevant parameters were obtained.