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Dielectric properties of a curing epoxy/amine system at microwave frequencies
Author(s) -
Finzel Mark C.,
Hawley Martin C.,
Jow Jinder
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.760311614
Subject(s) - materials science , dielectric , epoxy , arrhenius equation , activation energy , curing (chemistry) , relaxation (psychology) , dipole , stoichiometry , cole–cole equation , microwave , composite material , polymer chemistry , thermodynamics , chemistry , organic chemistry , psychology , social psychology , physics , optoelectronics , quantum mechanics
Dielectric data collected at 2.45 × 10 9 Hz has been analyzed using a mean relaxation time model over the temperature range 50 to 100°C and at extents of cure from 0 to 57% for a stoichiometric DER 332 (Dow)/DDS (Aldrich) mixture. The relaxation times thus obtained obey the Arrhenius law and tend to increase with the extent of cure. This corresponds to the more rigid nature of the molecular structure as the network forms and the dipolar relaxations become more inhibited. Decreases in the activation energy of the relaxation along with a widening of the relaxation time distribution imply that the relaxations involve ever shorter chain segments as the extent of cure increases.