Abstract: Finely-divided dispersed solids are prepared by the emulsion polymerization in the presence of a free radical catalyst of a major amount of an ethylenically unsaturated monomer or mixture of monomers and a minor amount of a hydroxy-terminated organic compound having from one to eight hydroxyl groups, an oxyethylene content of from about 15 to 80 weight percent, a hydroxyl equivalent weight of from 250 to 10,000 and containing a polymerizable carbon-to-carbon double bond. The resulting polymeric solids are particularly useful in the preparation of reinforced polymer compositions.