含叔丁基/异丁基二胺的可溶性透明聚酰亚胺的合成与性能

通过分子设计合成了异丁基桥联2-叔丁基苯胺的新型二胺单体4,4′-(2-异丁基)双(2-叔丁基苯胺), 并将其分别与4种商品化芳香族二酐经高温“一步法”缩聚制得了系列聚酰亚胺(PI)树脂. 采用多种测试手段研究PI的结构和性能, 结果表明, 该系列新型聚酰亚胺不但可溶于N-甲基吡咯烷酮及N,N-二甲基甲酰胺等高沸点溶剂, 而且在乙酸乙酯和三氯甲烷等低沸点溶剂中也具有良好的溶解性. 该系列PI保持了良好的热稳定性, 在N₂中5%热失重温度均在480 ℃以上, 玻璃化转变温度(T_g)介于307~356 ℃之间. 经溶液刮涂制得的PI薄膜具有良好的光学透明性, 在可见光区平均透过率可达82.3%~89.1%, 截止波长介于313~363 nm之间. 同时, 该系列PI薄膜还具有良好的机械性能和疏水性, 有望应用于光伏发电及柔性显示等领域.

Synthesis and Properties of Soluble Transparent Polyimides Containing tert-Butyl and Isobutyl Groups

A novel diamine containing tert-butyl and isobutyl groups｛4，4′-（2-isobutyl）bis［2-（tert-butyl） aniline］， IBBTBA｝ was synthesized from 2-tert-butyl aniline and isobutyraldehyde. Then a series of polyimides（PIs） was prepared from IBBTBA and four aromatic dianhydrides by the high-temperature one-plot polymerization. The structure and properties of the PIs were investigated in detail. The results indicate that all PIs show good solubility not only in high-boiling aprotic solvents［N-methylpyrrolidone（NMP）， N，N-dimethylacetamide（DMAc）， etc.］， but also in low boiling point solvents［ethyl acetate（EA）， CHCl₃， etc.］. They can be processed into flexible films easily by the solution casting or blade coating. All the resulting PI films（around 25 μm in thickness） have good transparency with the average transmittance from 82.3% to 89.1% and the cut-off wavelength from 313 nm to 363 nm in the visible light region. Satisfactorily， all PIs still maintain the good thermal stability. Their 5% mass loss temperatures（in N₂） are above 480 ℃ and T_g values are in the range from 307 ℃ to 356 ℃. Besides， all PIs films exhibit good mechanical properties and hydrophobicity. In summary， these PI films are potential candidates for applications in the fields of photovoltaic power generation， flexible display and so on.