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Application of compensation phenomena to the thermal analysis characterization of polymers: Introducing the degree of disorder (DOD) number:
Author(s) -
Ibar J. P.
Publication year - 1991
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760312005
Subject(s) - arrhenius equation , enthalpy , thermodynamics , relaxation (psychology) , activation energy , kinetic energy , materials science , compensation (psychology) , degree (music) , glass transition , polymer , condensed matter physics , nuclear magnetic resonance , physics , chemistry , quantum mechanics , psychology , social psychology , acoustics , psychoanalysis
The objective of this article is to show that a deconvolution of the global T g relaxation peak obtained by thermal stimulated current characterization technique leads to a better understanding of the coupling characteristics between the relaxation modes. The degree of coordination, i.e., coupling, is function of the state of the system and is revealed by the compensation phenomenon characteristics. In a compensation phenomenon, Arrhenius lines gather into packs of lines which converge to a single point, “the compensation point”. The coordinates of the compensation point are dependent on the actual state of the glass. We find that plots of the thermo‐kinetic variables against the polarization temperature T p , when T p varies, leads to characteristic results of the Relaxation Map: T g is characterized by a maximum of the Entropy of activation (and of the enthalpy of activation), and also by the existence of two compensation lines, one positive one negative, which intercept for T p = T g . The relaxation map looks like a “ Z ” across T g , as the Arrhenius relaxation lines gather into either a positive or negative compensation. We introduce a new method to characterize T g , and to determine, from the Z ‐structure, the activation entropy Δ S g , and the activation enthalpy Δ H g at T g .