Features of the quasi-brittle fracture of dense-network epoxide polymers modified with rubbers

• Published in: Polymer science USSR 1985, Vol.27 (4), p.846-853
• Main Authors: Volkov, V.P., Aleksanyan, G.G., Berlin, Al.Al, Rozenberg, B.A.
• Format: Article
• Language: English
• ISSN: 0032-3950; 1878-268X
• DOI: 10.1016/0032-3950(85)90422-8

The quasi-brittle fracture of epoxide-rubber compositions, characterized by different degrees of phase separation, has been investigated. The presence of hetero-phase rubber particles in the rigid matrix causes the appearance of additional mechanisms that are responsible for an increase in the effective fracture energy γ: these mechanisms involve interaction between cracks and particles and the facilitation of shear between particles. The crack-particle interaction is effective when the mean particle size, − d r , is equal to or greater then the critical size of the plastic deformation zone at the crack tip, d cr, as well when chemical bonds between the particles and matrix are present. The facilitation of shear deformation in the matrix between particles depends slightly on the presence of chemical bonds between the particles and the matrix and is effective if − d r < d cr. A composition with a bimodal particle-size distribution should have the maximum possible value of γ.