The aim of this study is to evaluate toughness mechanism of elastomeric poly(methyl methacrylate) (PMMAe) and polycarbonate (PC) blend through crack propagation at high speed tensile tests. Samples are processed using two types of extruders, single and twin screw, in order to eliminate the influence of processing in the final product’s properties. Pure polymers and polymer blend samples are cryo-ultramicrotomed and their morphology is characterized using atomic force microscopy (AFM). Fractured samples obtained from uniaxial tensile tests at high strain rate are inspected using optical microscopy (OM) and scanning electron microscopy (SEM). The results obtained for the PMMAe/PC blend in tests at high deformation rate showed that the shear rate during the mixing process influences the maximum strength of the polymer blend near its region of co-continuous morphology. The visual evaluation of the fracture surface and the fractographic analysis corroborated the results of this study of polymer toughening2031-12