Three kinds of core-shell polyacrylate latices (abbreviated to P(BA-EHA)

ACR I and ACRⅡ) were synthesized by muhi-stage emulsion polymerization．Butyl acrylate

2-ethylhexylacrylate and 1

4-butanediol diacrylate were used as components of the ACR core

while butyl acrylate/2-ethylhexylacrylate or methyl methacrylate/styrene or methyl metbacrylate/ethyl acrylate were employed as components of the ACR shell

respectively．Using ACR latices as seeds

three kinds of ACR-g-PVC resin were prepared by seeded emulsion co-polymerization with vinyl chloride． The structure and sizes of ACR and composite latex particles were investigated through transmission electron microscopy and dynamic laser scattering method．The morphology and impact toughness of the obtained materials were characterized．It was found that the notched impact strength of the three kinds of ACR-g-PVC materials at room temperature was enhanced with an increasing ACR content．The abrupt increment of the notched impact strength for the ACR-g-PVC materials happened at the same rubbery content of about 4％．This was explained by the change of interparticle distance. The toughening efficiency of P(BA-EHA) was higher than that of ACR I or ACRⅡ．The toughening efficiency of ACR in the materials was discussed according to two ideal-structure models of the ACR-g-PVC composite particles．