Toughening of epoxy resin systems using core–shell rubber particles: a literature review

Excellent thermal and mechanical properties and high chemical resistance with low shrinkage of epoxy resins open a wide window of various industrial applications, including coatings, paints, adhesive, etc. Despite their excellent properties, epoxy resins are brittle and have a low resistance to the initiation and growth of cracks. To overcome this drawback, different kinds of reinforcements, including liquid rubbers, core–shell rubber particles, dendritic polymers, block copolymers, thermoplastics, rigid particles, etc., have been used to improve the fracture toughness of epoxy resin systems. This paper briefly introduces each reinforcement separately and mainly presents an in-depth review of the progress of the last decade in the field of toughening of epoxy resins using core–shell rubber particles. This review paper also refers to the results of the research papers published on the effect these rubber particles on the mechanical properties of epoxy resins, as well as explains different toughening mechanisms of epoxy resins. Researchers first focused on the use of core–shell rubber particles containing different cores and shells. They then used core–shell rubber particles along with rigid fillers such as silica to offset the slight diminish in mechanical properties, as well as the glass transition temperature. In recent years, some research teams have used core–shell rubber particles and block copolymers simultaneously and have achieved fascinating results.