However, interfacial adhesion has been reported to have little direct effect on the toughness of the polymer–rubber blends at low strain rates. Dompas and coworkers [6] investigated the effect of interfacial adhesion on the stress–strain curves of the PVC–MBS blends by using a constant volume fraction of MBS particles of size of 0.25 mm. They concluded that the interfacial adhesion has no influence on the stress–strain behavior of the blends. Huang and coworkers [7] found that interfacial adhesion has only a small effect on the fracture behavior of rubber-toughened epoxies. Cho and coworkers [8] investigated the effect of interfacial adhesion on the fracture toughness of the poly(methyl methacrylate) (PMMA)–rubber blends determined by three point-bending tests. By studying the fracture toughness as a function of the rubber particle size at a constant rubber content, they concluded that interfacial adhesion does not have any influence.