Abstract:

The phosphorus-containing diamine compound, bis(4-aminophenoxy)-phenyl phosphine oxide(DAPOPO) was synthesized. The solutions of polyamic acid(PAA) prepared from DAPOPO and 4,4'-oxydianiline(ODA) with pyromellitic dianhydride(PMDA) and 3,3',4,4'-biphenyl tertracarboxylic dianhydride(BPDA) were used for PAA fiber spinning with two-step process by dry-jet wet spinning. The polyimide(PI) fibers were obtained from PAA fibers by the process of the thermal imidization and hot dra-wing. The morphologies, mechanical properties, thermal properties and flame retardant properties of PI fibers were systematically investigated by the scanning electron microscopy(SEM), fiber mechanical property tester, thermogravimetric analyzer(TGA) and limiting oxygen index(LOI) value tester, respectively. The results indicate that thermal stability of the PI fibers is obviously enhanced with increasing phosphorus content. The value of LOI is increased from 35 to 45. These powerfully demonstrate that the flame retardant of PI fibers have been significantly enhanced.

Key words: Phosphorus-containing polyimide fiber, Thermogravimetric analysis, Flame retardant property, Limiting oxygen index(LOI)