Nanocomposites wele prepared by a simple technique of emulsion polymerization using VC monomer and Na+ -montmofillonite．The nano-structure of the composites was studied with the aid of X-ray diffraction and transmission electron microscopy．and the mechanical and thermal properties of the composites were also tested．The results showed that the silicate layers were delaminated or partially exfoliated in the PVC matrix．The impact strength of the material with 2.1％ MMT was almost two times as high as that of pure PVC．while the tensile strength decreased little．However

the mechanical strength of the composites began to decrease with further increasing the amount of MMT．The TGA results showed that the temperature

at which a 50％ weight loss of the composites occurred．was highel-than that of pure PVC The vicat softening temperatures of composites were enhanced with increasing MMT content．