Techniques for studying the mechanisms of chemical corrosion in fiber-reinforced plastics are of considerable importance. The most common analysis technique for studying chemical changes in polymers is Fourier transform infrared (FT-IR) spectroscopy. For polymers reinforced with graphite fibers, however, study of the matrix is hindered by the presence of the graphite, which strongly absorbs IR radiation in a broad band of wavelengths. The purpose of this study was to investigate the degradation of AS-4/3501-5a graphite/epoxy composite material exposed to solutions of hydrogen peroxide. Evidence was also sought for degradation in high pH (up to pH = 12) solutions. After long-term environmental exposure, a simple gravity flotation technique was used to separate the epoxy matrix from the graphite fibers for FT-IR analysis. The resulting spectroscopic evidence indicates that hydrogen peroxide attacks the secondary amines in the cured epoxy structure. No evidence of attack by high pH solutions was found.
Forrest E. Sloan, "Chemical Attack of Graphite/Epoxy by Hydrogen Peroxide," Appl. Spectrosc. 46, 524-528 (1992)