Influence of electron irradiation on the mobility and on the mechanical properties of DGEBA/TETA epoxy resins

The thermomechanical properties of DGEBA/TETA resins are analysed as a func tion of the irradiation dose. Irradiation by electrons results in a decreas e of the glass transition temperature and the elastic modulus in the rubber y region. The Arrhenius diagrams obtained for the various doses show that t he cooperative mobility associated with the a: relaxation becomes faster af ter the irradiation. More local mobility corresponding to the beta and gamm a relaxations is also modified, but in a lesser extent. These results can b e interpreted invoking a destruction of the crosslinks within the resin. Th e effects of irradiation on the stress-strain curves are also discussed and are shown to be connected with both the physical aging kinetics and the sp atial heterogeneity of the crosslink density in the resin. (C) 2001 Elsevie r Science Ltd. All rights reserved.