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Influence of diamine structure on the low temperature dielectric relaxation of some poly(ether imide)s
Author(s) -
Eastmond Geoffrey C.,
Paprotny John,
Pethrick Richard A.,
SantamariaMendia Fernan
Publication year - 2015
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.41684
Subject(s) - polymer , dielectric , relaxation (psychology) , materials science , imide , diamine , polymer chemistry , activation energy , glass transition , ether , permittivity , steric effects , chemistry , organic chemistry , composite material , psychology , social psychology , optoelectronics
Broadband dielectric relaxation spectra are reported on a range of poly(ether imide) polymers in which the chemical structure of the diamine used to create the polymer is systematically varied with the anhydride structure based on 2,2‐bis‐[4‐(3′,4′‐dicarboxyphenoxy)phenyl]hexafluoroisopropylidine dianhydride. In all the polymers examined, a dipole relaxation was observed below room temperature. The magnitude and activation energy associated with the relaxation process varied with the chemical structure reflecting the effects of steric hindrance on the conformational change associated with the NC and COC linkages. Values of the activation energies varied between 29 and 34 kJ/mol −1 , and are consistent with the observed relaxation being associated with constrained local oscillatory motions of small elements of the polymer backbone. The glass transition temperatures of these polymers are in the range 195–243°C and are associated with the large scale motion of the polymer backbone. Changes in the backbone structure influence the extent of inter chain–chain interaction and are reflected in the amplitude of the relaxation process and the high frequency limiting dielectric permittivity ε ∞ values which are important when these polymers are used in thin film electronic applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41684.