Journal of Thermal Analysis and Calorimetry, Vol. 59 (2000) 625–632
STUDY OF THE CRYSTALLIZATION KINETICS
Poly(ethylene oxide) and a blend of poly(ethylene oxide) and
poly(bisphenol A-co-epichlorohydrin)
L. E. Cohen and A. M. Rocco
*
Departamento de Química Inorgânica, Instituto de Química, Universidade Federal do Rio de Janeiro
Centro de Tecnologia, Bloco A, Sala 637, Cidade Universitária, 21949-900, Rio de Janeiro, RJ, Brazil
Abstract
A kinetic study of the crystallization of poly(ethylene oxide) (PEO) and of a blend of PEO+poly-
(bisphenol A-co-epichlorohydrin) (PBE) was performed by using DSC in a non-isothermal program
at constant cooling rates. The curves obtained were analyzed by the Kissinger, Ozawa and Friedman
methods, with determination of the kinetic parameters in each case. As a consequence of the pres-
ence of PBE, the kinetic parameters were altered, leading to the conclusion that PBE has some influ-
ence on the crystallization of PEO, modifying its mechanism.
Keywords: crystallization, non-isothermal kinetics, poly(ethylene oxide)
Introduction
The crystallization of low molecular mass poly(ethylene oxide) (PEO) has previously
been studied by means of optical microscopy [1], isothermal methods in DSC [2–4],
DSC with tri-block copolymers [5] and temperature-modulated calorimetry [6].
Studies on the crystallization of high molecular mass PEO have also been performed
by using atomic force microscopy [7].
In the present work, the crystallization of high molecular mass PEO is studied by
using non-isothermal DSC measurements at constant cooling rates, and the effect of
blending with poly(bisphenol A-co-epichlorohydrin) (PBE) is investigated. Among
various methods suggested in the literature [8], we chose to apply the one peak maxi-
mum evolution method (Kissinger method) and two isoconversional methods
(Ozawa and Friedman methods).
Kissinger method
Kissinger [9] derives an expression (1) which makes it possible to calculate the acti-
vation energy of a process by analyzing DSC or DTA curves obtained at a number of
heating or cooling rates, regardless of the reaction order:
1418–2874/2000/ $ 5.00
© 2000 Akadémiai Kiadó, Budapest
Akadémiai Kiadó, Budapest
Kluwer Academic Publishers, Dordrecht
* Author for correspondence: e-mail: amrocco@iq.ufrj.br