Premium
Enthalpy recovery in polymeric glasses: Does a correlation exist between the empirical (T‐N‐M) relationship parameters and the glass structures?
Author(s) -
Saiter J. M.,
Denis G.,
Grenet J.
Publication year - 1999
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19991480104
Subject(s) - polymer , enthalpy , thermodynamics , materials science , intermolecular force , epoxy , relaxation (psychology) , polymer chemistry , molecule , organic chemistry , chemistry , composite material , physics , psychology , social psychology
To characterize the enthalpy recovery which appears during physical aging in glassy materials and especially in glassy polymers, the empirical Tool‐Narayanaswamy‐Moynihan (TNM) relationship for the relaxation time is widely used. This relationship depends essentially on three parameters, the apparent activation energy Δh*, the non linearity parameter x and the fictive temperature T f . Even if a great amount of data (x, Δ*) can be found in the literature, no direct correlation between the values of these parameters and the engaged structures are available. On the one hand, using some polymers like Poly(ethylene terephthalate), Polymethyl(α‐n‐alkyl)acrylates and three dimensional epoxy networks for which structural changes are controlled and on the other hand, using some recently published results concerning other materials including inorganic polymers (Ge‐Se and Ge‐Te glasses), we show that it is possible to propose some interesting tendencies. In particular it is shown that the value of x depends on the intermolecular strength for organic polymers and on the connectivity for inorganic polymer.