Modelling of the toughening mechanisms in rubber-modified epoxy polymers

A mathematical model has been developed to quantify the relationships between the microstructure and fracture properties of multiphase rubber-toughened epoxy polymers. Good agreement between predictions from the model and experimental results have been found. The model also reveals that localized plastic shear banding in the epoxy matrix, running between the rubbery particles, is the dominating mechanism under all testing conditions. Plastic void growth in the epoxy matrix is the other main toughening mechanism. This latter mechanism is initiated by internal cavitation of the rubbery particle, or by debonding at the particle-matrix interface, and is particularly significant at higher test temperatures.