一类含酚酞结构高可溶性聚酰亚胺的合成与性能

Synthesis and properties of a series of highly soluble polyimides containing phenolphthalein structures

摘要:

以百里香酚酞（5,5’-二异丙基-2,2’-二甲基酚酞）与对氟硝基苯为起始原料，通过芳香亲核取代和氧化还原反应得到新型芳香二胺单体——5,5’-二异丙基-4,4’-二氨基苯氧基-2,2’-二甲基酚酞。进一步由该二胺单体分别与三种商品化芳香二酐（3,3’,4,4’-二苯醚四甲酸二酐、3,3’,4,4’-二苯酮四羧酸二酐和3,3’,4,4’-联苯四甲酸二酐）以一步法高温缩聚制备得到一系列同时含酚酞Cardo结构及异丙基和甲基侧基的高可溶性聚酰亚胺（PI-1，PI-2和PI-3）。该类聚酰亚胺具有优异的溶解性，室温下不仅可溶于高沸点溶剂N-甲基吡咯烷酮（NMP），N,N-二甲基乙酰胺（DMAc）和N,N-二甲基甲酰胺（DMF），二甲基亚砜（DMSO），而且能溶于低沸点溶剂氯仿（CHCl3），二氯甲烷（CH2Cl2）和四氢呋喃（THF），并可方便的通过其溶液浇筑制备得到系列高性能聚酰亚胺膜材料。所制聚酰亚胺膜材料具有较高的光学透明性，其截断波长在324 nm~365 nm之间，450 nm的透过率在56%~78%之间。该类膜材料玻璃化转变温度在266 ℃~289 ℃，在N2和O2下的T10%的热失重在430 ℃以上。其相关力学拉伸强度在77 MPa ~95 MPa，弹性模量在1.2 GPa ~1.5 GPa，1MHz下介电常数在2.79~3.01，表现出良好的力学性能和介电性能。

Abstract:

A new aromatic diamine monomer which contains phenolphthalein structure, isopropyl and methyl groups was prepared by thymolphthalein and 4-fluoronitrobenzene through aromatic nucleophilic substitution and oxidation-reduction reaction. Furthermore, a series of high soluble polyimides (PI-1, PI-2 and PI-3) were prepared through one step high temperature condensation polymerization with the new diamine monomer and three commoditized aromatic dianhydrides (4,4’-oxydiphthalic anhydride, 4,4’-arbonyldiphthalic anhydride and 4,4’-biphthalic anhydride). The obtained polyimides were not only dissolved in high boiling point solvents, such as NMP、 DMAc、DMF and DMSO at room temperature, but also could dissolve in low boiling point solvents, such as CHCl3, CH2Cl2 and THF. The polyimides could be easily prepared for film materials by solution casting method. The prepared polyimide films have better optical transparency. Their cut-off wavelengths were between 324 nm to 365 nm, and their transmittance at the wavelength of 450 nm was in the range of 56%~78%. Their glass transition temperatures were between 265 ℃ and 288 ℃, and their temperatures of 10% weight loss were both beyond 430 ℃ in N2 and O2. Meanwhile, these polyimides exhibited good mechanical and dielectric properties. Their tensile strength and elongation at break ranged from 77 MPa to 95 MPa and 9.1% to 13%, and their dielectric constants were in the range of 2.79~3.01 at 1MHz.