Toughening of epoxy resin with microspheres

Special microspheres dispersed in epoxy resin prior to curing can toughen brittle resin by formation of a second phase. In this work, rigid particles (HP), hollow particles (PO) and rubber powders (PR) are used to modify epoxy resins for the study on the toughening mechanism. The single-edge notched three-point bending test and T peel test have been used to measure the toughness of epoxy resin. The morphology (particle/matrix interfacial shape) of epoxy resin modified with these three kinds of microspheres has been investigated by transmission electron microscopy (TEM). The results show that these three kinds of modifiers are all effective, and the core-shell rubber particle (PR) is the best toughening modifier among them. It is also found that the toughening effect is dependent on the morphology of the interface between the particles and matrix and the different curing conditions really result in obviously different interface states. The excellent interfacial interaction plays a significant role in toughening epoxy resin.