碱催化聚酰亚胺/二氧化硅杂化薄膜 的制备与微相结构研究

采用碱催化正硅酸乙酯的溶胶/凝胶工艺制备了一系列透明聚酰亚胺/二氧化硅（PI/SiO2）纳米杂化薄膜。对碱催化条件下的正硅酸乙酯（TEOS）溶胶影响因素进行了分析和讨论，并优选出了稳定溶胶的制备条件：各组分的摩尔比为：n(H2O)∶n(NMP)∶n(TEA)∶n(Si)= 3∶3.75∶0.1∶1，处理温度为50 ℃。对杂化薄膜的微观形貌和结构分别进行了扫描电镜（SEM）和红外光谱（FTIR）分析，结果表明，杂化薄膜都具有很高的光学透明性；随着SiO2含量的增加，杂化薄膜的微观形貌变化不大。SiO2含量增加到30 %(wt)时，SiO2粒子尺寸仍在100 nm左右。通过对其微相结构和形貌的中间演化过程研究发现，SiO2粒子形成于杂化薄膜初期。聚酰胺酸发生酰亚胺化反应的温度也受残留碱的影响而有所降低。

Study on Preparation and Morphology of the Polyimide/Silica Hybrid Films Derived from Base Catalyzed TEOS

A series of transparent polyimide/silica (PI/SiO2) hybrid films were fabricated via sol-gel process using hydrolyzed tetraethoxysilane (TEOS) under base condition. The influence factors on the preparation of stable sol by TEOS were discussed. The chemical structure and morphology of hybrid films were characterized by FTIR and SEM. The results show that, when increasing silica content, the diameter of SiO2 particles does not change considerably. The diameter of the SiO2 particles remains about 100 nm when silica content reaches 30 %(wt), almost the same with the size at 7 %(wt) silica content. The residual base catalyst results in increasing imidization degree at the same curing temperature. The final morphology of the hybrid is formed at the beginning of the phase separation.