Characterization and degradation of hydrogen-bonded acidic polyamideimides linked by disiloxanes

摘要

Hydrogen-bonded acidic poly(siloxane amideimide)s (PSAIs) were synthesized by partial imidization of 3,3',4,4'-benzophenone- tetracarboxylic dianhydride (BTDA) with 2,2',bis(3-amino-4-hydroxyphenyl hexafluoropropane (AHHFP) and 1,3-bis(3-amino- propyl)tetramethyldisiloxane (APrTMDS). Infrared (IR ) and ~13C nuclear magnetic resonance (NMR) spectroscopies characterized the structure of PSAI copolymers. The apparent activation energy E_a of degradation of PSAI copolymers in air was studied by thermogravimetry and compared with unmodified polyamideimide (PAI). The higher E_a of the PSAIs in air 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 closely packed structure with increasing APrTMDS.