Abstract: PBA latex was synthesized by emulsion polymerization，onto which acrylonitrile and styrene monomers were grafted. The grafted product was melt blended with SAN copolymer forming an ASA resin. The effect of grafting monomers and PBA latex size on the structure and property of ASA resin was studied. It showed that the grafting degree was increased with increasing loading of grafting monomers，and the impact strength of ASA resin increased and then decreased with an increasing grafting monomers and PBA latex particle size. When the grafting monomers content was 3 wt % of BA monomer，ASA resin reached the maximum impact strength of 110 J/m. Dynamic mechanical thermal analysis (DMTA) showed that the Tg of the grafted PBA increased with increasing grafting monomers，decreased and then increased with increasing PBA latex size. Scanning electron microscope revealed that the PBA latex uniformly dispersed in SAN matrix with a few of particles coagulated.

Key words: Acrylate - Styrene – Acrylonitrile core - shell grafted copolymer, Acrylate – Styrene - Acrylonitrile blends, poly (butyl acrylate), rubber particle size, Styrene - Acrylonitrile copolymer, grafting agent