PIPD, a new high-modulus and high-strength polymer fibre with exceptional fire protection properties

The development of the new high-modulus and high-strength fibre M5, made of poly{2,6-diimidazo[4,5-b:4',5'-e]pyridinylene-1,4(2,5-dihydroxy)phenylene} or PIPD, has resulted in an organic polymer fibre with exceptional fire protection properties when compared with PBO, Twaron, Kevlar and Nomex fibres. The PlPD as-spun fibre with a modulus of 150 GPa and a tensile strength of 2.5 GPa is a crystal hydrate containing 21 wt% water. Cone calorimeter measurements yielded a fire performance index (FPI) 20 times higher than Nomex, with extremely low value for the specific extinction area (SEA) characterizing the smoke formation. The PIPD-HT fibre (recrystallized in an after treatment into the anhydrous crystalline structure) with a modulus > 300 GPa and a strength > 5 GPa has a FPI value similar to PBO but shows much less smoke formation than this fibre. Copyright (C) 2002 John Wiley Sons, Ltd.