A latex interpenetrating polymer network (LIPN), consisting of poly(n-butyl acrylate), poly(n-butyl acrylate-co-ethylhexyl acrylate), and poly(methyl methacrylate-co-ethyl acrylate) and labeled PBEM, with 1,4-butanediol diacrylate as a crosslinking agent was synthesized by three-stage emulsion polymerization. The initial poly(n-butyl acrylate) latex was agglomerated by a polymer latex containing an acrylic acid residue and then was encapsulated by poly(n-butyl acrylate-co-ethylhexyl acrylate) and poly(methyl methacrylate-co-ethyl acrylate). A polyblend of poly(vinyl chloride) (PVC) and PBEM was prepared through the blending of PVC and PBEM. The morphology and properties of the polyblend were studied. The experimental results showed that the processability and impact resistance of PVC could be enhanced considerably by the blending of 6-10 phr PBEM. This three-stage LIPN PBEM is a promising modifier for manufacturing rigid PVC. (C) 2003 Wiley Periodicals, Inc.