STUDY ON THE TOUGHENING MECHANISM OF RUBBER TOUGHENED EPOXY RESIN

The following affecting factors of rubber toughened epoxy resin system were studied: 1. kinds of curing agent used 2. the Mc value of the matrix 3. the bonding force between the dispersed phase and the matrix. Accoring to our experimental results, the average chain length between crosslinks (Mc) is found to be a much more important affecting factor, chemical bonding between the dispersed phase and the matrix is also important. A toughening mechanism of rubber toughened epoxy resin has been proposed. In the material with relatively low cross-linking density, extensive fracture process stripe is formed which is induced by the combined stress field near the rubber particles. The chemical bonding between the dispersed phase and the matrix may increase the strength of the local stress field about the rebber particles which is in favor of broading the fracture process area.