溶胶—凝胶法制备聚酰亚胺/二氧化硅纳米尺度复合材料

Preparation of PolyimideSilica Nanocomposite Films by SolGel Process

通过正硅酸乙酯（ＴＥＯＳ）在聚酰胺酸（ＰＡＡ）的Ｎ，Ｎ－二甲基乙酰胺（ＤＭＡｃ）溶液中进行溶胶－凝胶反应，制备出一系列二氧化硅含量不同的聚酰亚胺／二氧化硅（ＰＩ／ＳｉＯ２）复合薄膜材料．二氧化硅质量分数（ω）低于１０％的样品是浅黄色的透明薄膜；二氧化硅ω高于１０％的样品是棕黄色不透明薄膜．利用ＩＲ、ＴＧ、ＳＥＭ、ＴＥＣ和应力应变测试等方法研究了此类材料的结构与性能．结果表明，二氧硅含量较低时，可达到纳米尺度的分散．ＰＩ／ＳｉＯ２复合材料与ＰＩ相比，仍具有较高的热稳定性和更高的模量，线性膨胀系数降低；拉伸强度和断裂伸长随ＳｉＯ２含量增加而降低．

A series of polyimide/silica composite films with different silica content were successfully prepared by the solgel reaction of tetraethoxysiliane in the solution of polyamic acid in N,Ndimethylacetamide. The films with silica content less than 10 wt% were yellow and transparent, whereas the films with silica content more than 10 wt% were yellow and opaque. Their structure and physical properties were investigated by SEM, IR, TG, TEC and stressstrain analysis. Silica particles with diameter of around 0.5 μm were observed in the hybrid film with containing 10 wt% silica. Compare with the PI film, PI/SiO 2 hybrid films still maintain outstanding thermal stability and higher modules. The linear thermal expansion coefficient of the composite films decreased to 2.42×10 -5 K -1 . The tensile strength and elongation at break of the films decreased with increasing the silica content.