Relationship between viscoelastic transition and yield behavior of phenolphthalein poly(ether ketone)

Abstract

The viscoelastic behavior of phenolphthalein poly(ether ketone) (PEK-C) and its relationship to yielding was studied. The following phenomena were observed: (1) The relaxation behavior at strain near yield closely approximated that at low strain but near the Tg; (2) the temperature and strain rate dependence of yield stress could be modeled by the one-process Eyring theory and the value of the activation volume was the same as that of the glass transition; and (3) according to the Zhurkov–Bueche equation, the α transition was related to the yield behavior. All these results indicated that the glass transition was the main factor that controlled the yield behavior. © 1996 John Wiley & Sons, Inc.