The Glass Transition Temperature (Tg) as a Parameter for Monitoring the Cure of an Amine-Cured Epoxy System at Constant Heating Rates
Abstract
A continuous heating transformation (CHT) diagram displ ays the time and temperature of events that a material encounters during the course of continuous heating at different heating rates. For thermosetting systems, these events include gelation, vitrification and devitrification. Analysis of isothermal data for a diglycidyl-type epoxy/tetrafunctional aliphatic amine system, which is initially liquid at room temperature, indicated that kinetic control applied prior to vitrification. The parameters so obtained (i.e., order of reaction, Arrhenius pre-exponential term, and activation energy) together with a relationship between Tg and extent of reaction were used as a basis for modeling the onset of vitrification and devitrification in the CHT diagram. For heating scans from below Tgo (glass transition temperature of the reactants), the initially glassy material will devitrify when the temperature reaches Tgo, except for very low heating rates for which initial devitrification is not encountered. Keywords: Cure, Vitrification, Glass transition, Kinetics, Time-temperature-transformation cure diagram, Continuous heating, Time-temperature-transformation cure.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1989
- Accession Number
- ADA206098
Entities
People
- G. Wisanrakkit
- J. B. Enns
- John K. Gillham
Organizations
- Princeton University