“…The mechanical properties of the heterogeneous polymeric systems including polymer blends depend on the microstructure of the sample, the size and shape of the domains, and the interactions among the components [1,2]. The reinforcement of a polymer by finely dispersed fillers was discussed previously [3] from the view point of its relationship to the degree of molecular orientation at break which is dependent on the strain developed at the break point and the nature of the stressed state. It was also found that, for this relationship, the effect of filler on the strength properties can vary under different conditions of fracture.…”