Anomalous Behavior of Cured Epoxy Resins: Density at Room Temperature versus Time and Temperature of Cure
Abstract
The room temperature density (RHO RT) of a difunctional aromatic epoxy resin cured with a tetrafunctional aromatic amine passes through a maximum value with increasing conversion. For a given cooling rate cure results in a unique value of (RHO RT) for each conversion as long as the material does not vitrify on cure. The occurrence of vitrification during cure eliminates the one-to-one relationship because of the non-equilibrium nature of the glass transition region and of the glassy state. In the glass transition region there is competition between physical aging which increases the density and chemical aging which decreases (RHO RT). Prolonged isothermal cure and physical aging to well beyond vitrification result in limiting values of (RHO RT) which decrease with increasing temperature of cure. Keywords: Vitrification, Glass transition, Kinetics, Physical aging.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1988
- Accession Number
- ADA197644
Entities
People
- J. K. Gillham
- K. P. Pang
Organizations
- Princeton University