The crosslinked poly(butyl acrylate-co-2-ethylhexyl acrylate)[P(BA-EHA)] latex was synthesized by emulsion polymerization．In the presence of P(BA-EHA) latex

P(BA-EHA)／PVC composite latex was prepared by copolymerization with vinyl chloride in an autoclave．The effects of the amount of P(BA-EHA) latex on the latex particle diameters and mechanical properties of P(BA-EHA)／PVC materials were investigated．The morphology of the materials or the composite latex particles was characterized with the aid of TEM or SEM and dynamic mechanical analysis (DMA)．DMA measurements illustrated that the compatibility between P(BA-EHA) and PVC was well improved．With increasing the P(BA-EHA) content

the loss peak in low temperature range became higher than that of pure PVC

and the maximum value of the loss peak gradually shifted to higher temperature．TEM studies showed that the composite particles had a clear core-shell structure

P(BA-EHA) uniformly dispersed in PVC matrix

the interface between the two phases was indistinct．The fractured surface of the notched sample exhibited clear toughness characteristics．The notched impact strength of the material with 4.2％ P(BA-EHA) was eleven times as large as that of PVC

and the elongation percentage at break was about three times that of PVC．