Toughening of epoxy networks using pre-formed core-shell particles or reactive rubbers

Abstract

The influence of several additives (liquid reactive rubbers or core-shell particles-CSR) is studied on thermal and mechanical properties of an epoxy network based on diglycidyl ether of bisphenol-A (DGEBA) and dicy (DDA). Using high speed stirring, without any solvent, a good dispersion of the CSR is achieved. It is shown that the glass transition temperature (Tg)of the networks decreases when liquid rubbers are added but remains constant with the addition of CSR. It is demonstrated that every kind of particles favors the shear yielding of the networks, and well fit a modified Von Mises criterion. The fracture energies increase with the addition of rubbers, especially for the rubber with the higher acrylonitrile content. The same toughening effect is obtained with CSR if compared to the lower acrylonitrile content of liquid reactive rubbers but without any decrease in Tg of the epoxy network.