通过分子设计合成了一种含叔丁基、醚键和双酚A单元的二胺单体2,2-二(3’-叔丁基4’-氨基二苯醚-4-基)丙烷(4),然后将其与4种商品化的芳香二酐单体:联苯四羧酸二酐(BPDA)、二苯醚四酸二酐(OPDA)、二苯六氟异丙基四酸二酐(6FDA)和均苯四酸二酐(PMDA)经高温“一步法”制备了一系列新型聚酰亚胺(PI)树脂,并对它们的结构与性能进行了研究.结果表明,该系列PI在NMP、DMF、DMAc、THF和CHCI,等普通有机溶剂中具有良好的溶解性;玻璃化转变温度Tg(DSC)在265-302℃之间,5%热失重温度(N2氛围)在519℃以上;在400~760nm可见光波长范围内,具有优异的光学透明性,透光率约等于或大于90%;PI的数均分子量(Mn,GPC)在1.90×10^4~3.90×10^4范围内,分子量分布(PDI)介于2.63~4.63之间,x-射线衍射(XRD)结果表明所得PI为无定形聚合物,吸水率低于0.5%.叔丁基、醚键和双酚A单元同时引入具有协同效应,可提高PI的溶解性和透明性,并保持PI原有良好的热稳定性、机械性能和较低的吸水率.
A novel diamine monomer containing tert-butyl, ether linkages and bisphenol A unit,2,2-bis (3'- (tert-butyl)-,4'-aniline-bisphenyl-4-ehter) propane (4), was designed and synthesized from 2-tert-hutylaniline and bisphenol A. Then it was polymerized with several commercial aromatic dianhydrides, including OPDA, PMDA,6FDA and BPDA,via one-pot method to afford a series of aromatic polyimides. Their chemical structures are confirmed by NMR,FTIR and EA measurements. The number-averaged molecular weights of the resulting PIs are in the range from 1.9× 10^4 to 3.9 × 10^4 with PDI from 2. 63 to 4. 63 by GPC measurements. They exhibit excellent solubility in many organic solvents, such as NMP, DMF, m-cresol, DMAc, THF and CHC13 ere, which can be attributed to the incorporation of tert-butyl groups and bisphenol A units into their rigid backbones. They can form transparent films by solution casting and the light transparency was equal to or higher than 90% in the visible light range from 400 to 760 nm. The XRD results demonstrate that they are amorphous glassy polymers. Furthermore, their inherent outstanding performance is still retained, including the high 5% weight loss temperature in nitrogen and Tg,good mechanical properties and low water absorption rates.