Facile and efficient preparation of phosphinate‐functionalized aromatic diamines and their high‐ T g polyimides

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2009-05, Vol.47 (10), p.2486-2499
• Main Authors: Chang, Chia Wei, Hsuan Lin, Ching, Wen Cheng, Po, Hwang, Hann Jang, Dai, Shenghong A.
• Format: Article
• Language: English
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.23320

Two novel phosphorus‐functionalized aromatic diamines, 1,1‐bis(4‐aminophenyl)‐1‐(6‐oxido‐6H‐dibenz oxaphosphorin‐6‐yl)ethane ( 1 ) and bis(4‐aminophenyl)‐(6‐oxido‐6H‐dibenz oxaphosphorin‐6‐yl)phenylmethane ( 2 ), were prepared from 9,10‐dihydro‐oxa‐10‐phosphaphenanthrene‐10‐oxide, 4‐aminoacetophenone, or 4‐aminobenzophenone in excess aniline using p ‐toluenesulfonic acid monohydrate as catalyst by an efficient, one‐pot procedure. The effect of electron withdrawing/donating groups on the stabilization of the resulting carbocation seems critical for the success of the process and was discussed in detail. Based on diamines ( 1–2 ), a series of new polyimides, (5a–5d) and (6a–6d) , were prepared, respectively. Polyimides (5a–5d) are flexible and creasable. In contrast, polyimides (6a–6d) are brittle because of the structure rigidity, according to the analysis based on the NMR temperature‐dependent spectra of ( 2 ). Polyimides 5 displaying high T g (318–392 °C), high moduli (3.39–4.49 GPa), low coefficient of thermal expansion (42–50 ppm/°C), and moderate thermal stability ( T d 5 wt % at 426–439 °C), are excellent high‐ T g and flame‐retardant materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2486–2499, 2009