Abstract
Correlations between fracture properties and microscopic features were investigated using notched (both blunt notched and sharp notched) specimens of rubber-PMMA composites in very low-to-medium range of cross-head speeds. It is found that: (1) the decreasing trend of crack initiation region size with increasing speed correlates with the fracture elongation; (2) the decreasing trend of SWZ size with increasing speed and decreasing rubber content can be correlated with that of calculated plastic zone and the trend correlates also with that in modulus of toughness; (3) the order of degree of material plastic flow at notch tip in the polymers correlates with the corresponding order of their K values.