Characterization and degradation of hydrogen-bonded acidic polyamideimideslinked by disiloxanes

Hydrogen-bonded acidic poly(siloxane amideimide)s (PSAIs) were synthesized by partial imidization of 3,3 ' ,4,4 ' -benzophenone-tetracarboxylic dianhy dride (BTDA) with 2,2 ' ,bis(3-amino-4-hydroxyphenyl) hexafluoropropane (AH HFP) and 1,3-bis(3-aminopropyl)tetramethyldisiloxane (APrTMDS). Infrared (I R) and C-13 nuclear magnetic resonance (NMR) spectroscopies characterized t he structure of PSAI copolymers. The apparent activation energy E-a of degr adation of PSAI copolymers in air was studied by thermogravimetry and compa red with unmodified polyamideimide (PAI). The higher E-a of the PSAIs in ai r than that of the PAI suggests that the disiloxane enhanced the stability of the polyamideimide, and the smaller spin-spin relaxation time T-2 Of the PSAI copolymers than that of the PAI reveals that the PSAI had more closel y packed structure with increasing APrTMDS. (C) 2001 Elsevier Science Ltd. All rights reserved.