There are three main types of epoxy resin toughening pathways:
1. The rigid inorganic filler, the rubber elastomer and the thermoplastic polymer form a two-phase structure for toughening.
2. Toughening and modification is carried out by continuously penetrating through the epoxy resin network to form a semi-interpenetrating network polymer.
3. Improve the activity of the crosslinked network by changing the chemical structure of the crosslinked network (such as introducing a "flexible segment" in the crosslinked network).