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Analysis of the Dielectric Response of Thermosets During Isothermal and Nonisothermal Cure
Author(s) -
Nass Kirk A.,
Seferis James C.
Publication year - 1989
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.760290509
Subject(s) - thermosetting polymer , isothermal process , materials science , dielectric , epoxy , relaxation (psychology) , composite material , thermodynamics , polymer chemistry , psychology , social psychology , physics , optoelectronics
Using dielectric techniques to monitor thermoset properties on‐line during processing requires a mathematical relationship between the experimentally obtained signals and the physical state of the polymer. Such a relationship accounting for the dielectric response during both isothermal and dynamic cure experiments is developed in this study. Ionic conductivity changes with cure were described using the Keinle‐Race expression, while an approach taken by Lane, Bachmann, and Seferis for modeling dipolar relaxation during isothermal cure was extended to nonisothermal cure conditions. Both of these approaches were combined in this study, providing a complete description of the dielectric changes occurring in thermosetting systems resulting from cure. Experimental results for a model epoxy/amine system were predicted with the developed methodology for isothermal cure at 140°C, 150°C, 160°C, and 170°C and cure under dynamic heating conditions at 1°C per minute.