DUCTILE TEARING INSTABILITY IN PHENOLPHTHALEIN POLY(ETHER KETONE)

Phenolphthalein poly (ether ketone) (PEK-C) [GRAPHICS] can fail by tea ring instability when the elastic contraction is greater than the plas tic extension due to crack growth. Tearing instability (TIS) theory de veloped by Paris and co-workers describes the effect of specimen geome try on the ductile fracture properties of polymers. The stability of c rack growth in three-point bend specimens depends on the specimen's di mensions. In this article, tearing instability theory is applied to de scribe the ductile tearing instability of PEK-C at different temperatu res. The temperature dependence of tearing modulus T(m), dJ/dDELTAa, a nd the relationship between dJ/dDELTAa and yield stress are discussed. (C) 1994 John Wiley & Sons, Inc.