VISCOELASTIC PROPERTIES OF PHENOLPHTHALEIN POLY(ETHER KETONE)

Stress relaxation and dynamic mechanical behavior of phenolphthalein p oly(ether ketone) (PEK-C) have been investigated. Using Ferry's reduct ion method, the master curve was obtained. From the experimental resul ts, we found that the WLF equation is not appropriate in the lower-tem perature range (T < T-g). The relaxation spectrum was calculated accor ding to the first approximation method proposed by Schwarzl and Staver man. In addition to the alpha-transition region, a second transition z one is revealed at low temperature. This transition is probably due to a restricted motion of its main chain. (C) 1995 John Wiley and Sons, Inc.