THE THERMOOXIDATIVE STABILITY OF FLUORINATED POLYIMIDES AND POLYIMIDEGRAPHITE COMPOSITES AT 371-DEGREES-C

Increasing demands to decrease engine weight and improve engine perfor mance has led to an investigation to develop polymer composites capabl e of being used at 371-degrees-C and above in 4 atmospheres of air. Th e results of an investigation to determine the thermo-oxidative stabil ity (TOS) of various fluorinated polyimides, 3F-PDA, 36F-PDA, Avimid-N , AFR700B, and other PMR-type resins and graphite composites containin g these polyimides at 371-degrees-C in air at 1 and 4 atmospheres are presented. Weight losses due to aging under these conditions are prese nted as the criteria for measuring the TOS. The data show that 3F-PDA and Avimid-N which have equivalent TOS, exhibit twice the TOS than tha t of AFR700B and other PMR-type resins. 36F-PDA exhibits even better T OS than 3F-PDA or Avimid-N. (C) 1994 John Wiley & Sons, Inc.