ULTRASONIC STUDY OF SUB-BETA RELAXATION IN EPOXIDES CURED WITH ALIPHATIC DIAMINES

In the bisphenol A-based epoxy resin made from different length prepolymers and Aliphatic Diamines, sub beta-relaxation were investigated. Low frequency dynamic and ultrasonic results suggest that the relaxation seems to follow Arrhenius type behavior. In addition, the beta-relaxation is observed separately from the main alpha-relaxation in the MHz range. The strength of beta-relaxation depends on the molecular length of prepolymer and the amount of curing agent used. This indicates that the relaxation arises from motion within an internal side group containing crosslinks.