Premium
Dielectric behavior at microwave frequencies of an epoxy resin during crosslinking
Author(s) -
Livi A.,
Levita G.,
Rolla P. A.
Publication year - 1993
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.1993.070500912
Subject(s) - diglycidyl ether , epoxy , dielectric , materials science , microwave , curing (chemistry) , polymer chemistry , dipole , bisphenol a , composite material , chemistry , organic chemistry , physics , optoelectronics , quantum mechanics
The dielectric behavior during the crosslinking process of a low molecular weight liquid diglycidyl ether of bisphenol‐A (DGEBA) and ethylenediamine, as the curing agent, has been investigated at microwave frequencies (0.1–10 GHz) by means of the time domain reflectometry. It was found that both the real and the imaginary part of the dielectric constant, which regularly decreased as the cure reaction proceeded, were mainly affected by the disappearance of specific dipolar species, whose relaxation time did not change significantly. A simple model based on disappearance of dipoles agrees with the experimental data and explains the coincidence between kinetic data obtained by dielectrometry and calorimetry. The microwave dielectric constant can thus be used to directly measure in real time the conversion of the reaction. © 1993 John Wiley & Sons, Inc.