酸碱处理对聚酰亚胺膜浸润性能及力学性能的影响

Effect of Acid-Base Treatment onWettability and Mechanical Properties of Polyimide Membrane

由于聚酰亚胺(PI)薄膜表面极性差、黏附性不好等缺点,限制了其综合性能的发挥。文中研究了氢氧化钠(NaOH)处理浓度对PI膜表面性能和力学性能的影响。采用傅里叶变换红外光谱、X射线光电子能谱(XPS)、扫描电镜、原子力显微镜及静态接触角和动态接触角分析分别对PI膜经酸碱处理前后的表面化学结构、表面元素分析、表面形貌、表面粗糙度及表面浸润性能进行了研究。利用拉力测试仪测试了不同NaOH浓度处理后的聚酰亚胺薄膜力学强度的变化。研究结果表明,PI膜表面的O/C比从未处理的27.70%增加到47.26%,表面能从27.65 mJ/m2提高到58.2 mJ/m2。XPS结果表明,PI膜表面C—O活性基团含量增加,薄膜表面浸润性增加。随着NaOH浓度的增大,薄膜的力学强度显著下降,这与NaOH的水解作用有关系。

Due to the poor polarity and poor adhesion of polyimide(PI)films,the comprehensive performance of PI films is limited.The effect of sodium hydroxide(NaOH)concentration on the surface and mechanical properties of PI films was studied.Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),atomic force microscopy(AFM)and static contact angle and dynamic contact angle analysis(DCAA)were used to analyze the surface chemical structure,surface morphology,surface roughness and surface wetting properties of PI films before and after acid and alkali treatment.The mechanical strength of polyimide films treated with different concentrations of NaOH was measured by tensile tester.The results show that the O/C ratio of PI film surface increases from 27.70%to 47.26%,and the surface energy increases from 27.65 mJ/m2 to 58.2 mJ/m2.The results of XPS show that the content of C-O active group on the surface of PI film increases,and the infiltration of PI film surface is increased.With the increase of the concentration of NaOH,the mechanical strength of the film decreases significantly,which is related to the hydrolysis of NaOH.