高透明性不对称聚酰亚胺的合成与性能研究

Synthesis and Characterization of Asymmetric Polyimides with High Transparency

采用1,4-双(3’-氨基-5’-三氟甲基苯氧基)联苯(m-TFDAB)为二胺单体,分别与两种联苯型二酐单体,3,3’,4,4’-联苯四甲酸二酐(s-8BPDA)以及2,3,3’,4’-联苯四甲酸二酐(a-BPDA)通过一步高温溶液缩聚法制备了两种聚酰亚胺材料PI-1(s-BPDA/m-TFDAB)与PI-2(a-BPDA/m-TFDAB)。研究结果表明,不对称化结构没有对聚酰亚胺材料的耐热性能、力学性能以及电性能产生显著影响。但可以显著增大聚酰亚胺在有机溶剂中的溶解性以及在可见光范围内的透明性。PI-2不仅可以溶解于极性非质子性溶剂中,而且在许多常规溶剂中也具有优良的溶解性能。PI-2薄膜在可见光波长范围内具有优良的透明性,450nm处的透光率达到86%。此外,该材料在氮气中的起始热分解温度超过580℃,而700℃时的残余重量百分数达到67%。

A series of polyimides had been prepared via one - step high temperature polycondensation procedure from 1,4-bis（3 ＇ -amino-5＇ -trifluoromethylphenoxy） biphenyl （ m - TFDAB） and 3,3＇ ,4,4, ＇ -biphenyltetraearboxylie dianhydride （s-BPDA） or 2,3,3＇ , 4＇ -biphenyltetraearboxylie dianhydride （a-BPDA） , respectively. Two polyimides, PI-1 （s-BPDA/m-TFDAB） and PI-2 （ a-BPDA/m-TFDAB） have been successfully prepared by one -step procedure, whose properties were widely researched. The results showed that asymmetry wouldn＇ t greatly affect the thermal and mechanical properties of the polyimides. On the contrary, asymmetry enhanced the solubility of the polyimides in organic solvents and increased the transparency of the PI film. PI-2 was soluble not only in polar aprotic solvents, but in many common solvents. PI-2 film showed good transparency in the visible light region with transmittance of 86% at 450nm wavelength. Furthermore, PI-2 exhibited good thermal stability with the initial thermal decomposition temperature of higher.than 580℃ in nitrogen and 67% of residual weight ratio at 700℃.