Compatibilization of polystyrene/poly(butyl methacrylate)/poly[(ethylene glycol) dimethacrylate] blends via concentrated emulsion polymerization

Two concentrated emulsions in water containing styrene and butyl methacrylate (BMA) as dispersed phases were prepared. Each of them contained a small amount of an amphiphilic macromonomer, poly[(ethylene glycol) dimethacrylate] (PEGD), in the continuous phase. The two concentrated emulsions were partially polymerized at 50 degrees C until conversions of about 22.5% were reached. They were then mixed mechanically and the mixture was subjected to complete polymerization. During the latter polymerization, homopolymers of styrene and BMA and copolymers of the two were generated. The copolymers, particularly the crosslinked structures, which were formed through copolymerization of PEGD with styrene and BMA at the interface of the latexes, provided compatibilizers for the homopolymers. This blend of homopolymers, copolymers and crosslinked structures possessed excellent toughness and processability. The blends were characterized by their gel content, and by X-ray photoelectron spectroscopy, rheometric testing, dynamic mechanical thermal analysis, transmission electron microscopy and impact strength measurements. (c) 2005 Society of Chemical Industry.