Abstract: Mechanical properties and rheological behavior of blends of polv(vinvl chloride)(PVC)，chlorinatcd PVC(PVC-C )，and MBS arc investigated.The Vicat softening temperature of the blend increased with increasing content of PVC-C. The tensile strength and flexural modulus also increased with increasing content of PVC-C, while the impact strength and elongation at break decreased. In addition，PVC-C increased the equilibrium torque. The melt viscosity of the blends was reduced by the introduction of MBS.

Key words: chlorinated poly(vinyl chloride), poly(vinyl chloride), methylmethacrylate-butadicn-styrene copolymer, blend, blending modification, mechanical property, rhcological behavior