Post-Vitrification Cure Kinetics of High Temperature Composite Resins: Implications for Characterization and Performance
Abstract
Many high-temperature composite resins, such as cyanate esters, require high temperatures in order to achieve complete cure. In such situations, incomplete conversion often persists in completely solidified "cured" samples, leading to potentially significant degradation in performance. Moreover, the very steep dependence of the glass transition temperature of the composite resin on the extent of cure leads to unusual cure effects such as 1) significant cure below the glass transition temperature 2) cure kinetics that involve extremely strong temperature dependence coupled with very weak dependence on cure time, and 3) unexpected conversion-property relationships (e.g. a decrease in elastic modulus with increasing extent of cure). These effects not only complicate the prediction of composite performance, they also make the determination of even simple properties such as the extent of conversion or glass transition temperature prone to large, difficult-to-detect errors. This paper describes and demonstrates newly developed characterization methods that combine multiple techniques to overcome these difficulties, and allow for a more complete description of the evolving glass transition temperature of composite resins during part fabrication, testing, and performance. In addition, the paper describes how insights into the unusual phenomena associated with resins that cure at high temperature can lead to design strategies for high-temperature composite resins that provide optimal performance.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 09, 2013
- Accession Number
- ADA596974
Entities
People
- Andrew J. Guenthner
- Christopher M. Sahagun
- Joseph M Mabry
- Josiah T. Reams
- Matthew C. Davis
Organizations
- Air Force Research Laboratory