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Physical aging of high‐performance thermoplastics: Enthalpy relaxation in PEK‐C and PES‐C
Author(s) -
Di Yingwei,
D'Amore Alberto,
Marino Giuliano,
Nicolais Luigi,
Li Binyao
Publication year - 1995
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1995.070570811
Subject(s) - differential scanning calorimetry , glass transition , enthalpy , phenolphthalein , relaxation (psychology) , materials science , ether , polymer chemistry , polymer , sulfone , stress relaxation , thermodynamics , chemistry , composite material , organic chemistry , psychology , social psychology , physics , creep
The developments of physical aging in phenolphthalein poly(aryl‐ether‐ketone) (PEK‐C) and poly(aryl‐ether‐sulfone) (PES‐C) with time at two aging temperatures up to 20 K below their respective glass transition temperatures ( T g = 495 and 520 K) have been studied using differential scanning calorimetry (DSC). Substantial relaxation within the aging course of several hours were observed by detecting ( T g ) decreasing during physical aging process at the two aging temperatures. The relaxation processes of both polymers are extremely nonlinear and self‐retarding. The time dependencies of their enthalpies during the initial stages of annealing were approximately modeled using the Narayanaswamy‐Tool model. The structure relaxation parameters obtained from this fitting were used to predict the possibility of physical aging occurring at their respective using temperatures. © 1995 John Wiley & Sons, Inc.