Matrix Ligament Thickness MLT

Wu [175-177] proposed that the MLT, i.e., surface-to-surface inter-particle distance is a fundamental parameter. For effective toughening, mean matrix ligament thickness (x) should be less than that of the critical value (xj where brittle-tough transition occurs. The x is independent of rubber volume fraction, particle size and characteristics of the matrix alone at a given test temperature and rate of deformation. For blends with dispersed spherical particles, the x can be related to the rubber particle size and rubber volume fraction ) by the following equation [177]  

The existence of critical MLT for effective rubber toughening can be explained [72, 177, 178] in the light of two basic mechanisms rubber cavitation followed by the formation of shear bands, and crazing. A low MLT maintains the connectivity of the yielding process, which then propagates over the entire deformation zone and makes 

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