SUSPENSION POLYMERIZATION PROCESS

摘要

The present invention is a method of making polymeric particles having a controlled size and size distribution. The method includes dissolving a polymer in a solvent to form a solution wherein the solvent is substantially immiscible with water. A suspension of droplets of the solution is formed in water containing a water soluble promoter and a stabilizer comprising a surfactant free copolymer by high shear agitation. The stabilizer includes (i) 55 to 95 percent by weight, of an addition polymerizable p-tert-bu'tyl styrene and/or (ii) 5 to 45 percent by weight, both based on total monomer weight, of an addition polymerizable ionic monomer. The solvent is removed from the droplets and the solidified polymer particles are separated from the water. The present invention provides polymer particles having a core of polymer coated with a layer of smaller particles of a copolymer of the stabilizer described in the method.