Characterization and degradation of some phosphorus-containing polyimides

摘要

Phosphorus-containing polyimides and polysiloxaneimides were prepared via phosphorylation of organosoluble polyimide. This was achieved by esterification of their hydroxyl groups with diphenylphosphoryl chloride. The phosphorylation was confirmed by infrared (IR), ~31P nuclear magnetic resonance (NMR) and phosphorus content analysis. The thermal decomposition behavior of the phosphorus-containing polyimide was investigated by thermogravimetry and compared with unmodified polyimide. The polyimide with higher phosphorus content displayed lower onset decomposition temperature and char yield. The apparent activation energies (Ea) were obtained following the methods of van Krevelen, Horowitz-Metzger, Coats-Redfern, and MacCallum-Tanner. It was shown that Ea for thermal degradation of imide segments decreased with increase in phosphorus content.