MONODISPERSE POLY(BUTADIENE STYRENE) PARTICLES BY DISPERSION POLYMERIZATION

Experimental conditions for preparing monodisperse, micron-size poly(b utadiene/styrene) particles by dispersion polymerization were investig ated. After some initial recipe development, the following variables w ere fixed: butadiene/styrene weight ratio (90/10), dispersion medium ( ethanol),polymeric stabilizer [poly(vinyl pyrrolidone), K-30], costabi lizer (sodium dioctyl sulfosuccinate), initiator (2,2'-azobisisobutryo nitrile), and polymerization temperature (70 degrees C). The primary p rocess variables investigated were the monomer/ethanol ratio (M/S), th e rpm of the bottle polymerizer, and the amount of free space (FS) in the polymerization bottles. The particle size varied from 0.77 to 1.8 mu m and was found to increase with increasing M/S and rpm, and decrea sing FS. (C) 1995 John Wiley & Sons, Inc.