基于酚酞结构共聚型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:

以邻甲酚酞与2-氯-5-硝基三氟甲苯为起始原料，通过两步有机反应——芳香亲核取代和氧化还原反应得到芳香二胺单体——4,4"-(2,2’三氟甲基)-二氨基苯氧基-3,3"-二甲基酚酞。利用共聚改性的思路，由两种二胺单体〔4,4"-(2,2"三氟甲基)-二氨基苯氧基-3,3"-二甲基酚酞和2,6-二氨基甲苯〕与一种二酐单体3,3",4,4"-二苯醚四甲酸二酐（ODPA）通过不同投料比以一步法高温缩聚制备得到同时含酚酞、三氟甲基和烷基结构系列共聚型聚酰亚胺。该系列共聚型聚酰亚胺具有优异的溶解性，在室温下不仅可溶于常见的高沸点溶剂：N-甲基吡咯烷酮（NMP），N,N-二甲基乙酰胺（DMAc）、N,N-二甲基甲酰胺（DMF）和二甲基亚砜（DMSO），在低沸点溶剂氯仿（CHCl3）、二氯甲烷（CH2Cl2）和四氢呋喃（THF）中也表现出优异的溶解性，可便利地通过其溶液浇筑制备得到系列高性能聚酰亚胺膜材料。该类膜材料玻璃化转变温度在275~314 ℃，其在N2和O2氛围中热失重10%时的温度分别为477~507 ℃和477~49 0 ℃。该类膜材料具有低的介电常数和良好的力学性能：其在1 MHz下介电常数在2.69~2.92之间，拉伸强度、弹性模量和断裂伸长率分别在80~92 MPa、1.2~1.8 GPa和9.2 %~13.5%之间。

Abstract:

A new aromatic diamine monomer with phenolphthalein and methyl groups was prepared by o-cresolphthalein and 2-chloro-5-nitrotrifluorotoluene through aromatic nucleophilic substitution and oxidation-reduction reaction. Then a series of copolymerized polyimides which contains phenolphthalein structure and bulky groups were prepared by diamine monomer (2d) and commercial 2,6-diaminotoluene (TDA) with ODPA in different proportions through using a variety of monomer copolymerization methods, the structure and performance of copolymerized polyimides were tested. The series copolymerized polyimides had excellent solubility, they were not only dissolved in high boiling point solvents, such as NMP、DMAc、DMF and DMSO, but also could dissolve in low boiling point solvents, such as CHCl₃, CH₂Cl₂ and THF at room temperature. Their glass transition temperatures were between 275~314 ℃, and their temperatures of 10% weight loss were in the range of 477~507 ℃ and 477~490 ℃, respectively. Meanwhile, these polyimides had low dielectric constants and good thermal properties. The dielectric constants of the polymer films ranged from 2.69 to 2.92 at 1MHz. The tensile strength, elastic modulus and elongation at break of copolyimides ranged from 80 MPa to 92 MPa, 1.7 GPa to 2.0 GPa, and 9.2% to 13.0%, respectively.