Premium
Evolutions of microstructure and dielectric behavior of epoxy based insulator‐insulator composites over long periods of time
Author(s) -
Vouyovitch L.,
Flandin L.,
Bessede J.L.,
Alberola N. D.
Publication year - 2006
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.22128
Subject(s) - epoxy , composite material , materials science , microstructure , dielectric , composite number , permittivity , insulator (electricity) , polymer , service life , dipole , polar , chemistry , physics , optoelectronics , astronomy , organic chemistry
Aging of epoxy based composites used as insulators in the industry are investigated. The analysis of a composite aged for 20 years in actual service conditions points out chemical degradations, a structural recovery, a tendency for particle debonding from the polymer matrix and with respect to the unaged sample, and no significant changes in the permittivity values measured at 50°C. To understand this latter result, a purely physical aging was carried out on fresh composites with similar formulation as the insulator aged 20 years in service. A detailed analysis of the changes in properties during physical aging is proposed. It is concluded that the constant ε′ value at 50°C found for the 20 years aged composite results from two opposite phenomena: an increase in the relative dipole amount due to structural recovery and/or the presence of polar species at the polymer/filler interface that both increase ε′ and the loss of polar species in the bulk that decreases the ε′. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3454–3464, 2006