ABSTRACT
This chapter provides a comprehensive, up-to-date understanding of how to toughen epoxy resins via rubber modification. This includes a brief review of recent developments in epoxy toughening, a brief overview of the use of effective experimental and numerical tools for studying the fracture behavior of epoxy systems, illustrations of important toughening mechanisms observed in rubber-toughened epoxies, and the mechanics and physics relating to the observed toughening mechanisms. Rubber stretching and tearing, also known as the rubber bridging mechanism, are proposed by S. Kunz and co-workers as a major toughening mechanism for rubber-modified plastics. In an effort to shed some light on how to toughen high-performance epoxies more effectively, research on the influence of types of rubber, particle size, and particle dispersion characteristics in toughening is being conducted. The thickness of the shell may not only help retain the shape of the core-shell butadiene rubbers particle during part fabrication but also potentially effect how the copolymers arrange themselves in the shell.
