Selective adsorption of polymer on freshly ground solid surfaces in soapless emulsion polymerization

摘要

AbstractSoapless emulsion polymerization of methyl methacrylate initiated by a redox system of sodium bisulfite and oxygen in water in the presence of limestone was carried out by grinding the limestone in a vibrating ball mill reactor. The effect of a fresh solid surface produced on the adhesion between the solid and polymer formed was investigated. Examination of the resulting compoaite powder by scanning electron microscope indicated that the polymer selectively adsorbed on sites of the simultaneously ground limestone, whereas nonselective adsorption was observed on the previously ground limestone. The selectivity can be explained by the heterogeneities on the solid surfaces and is attributed to the existence of active centers such as defects and disturbances in the crystal lattice. Using the new method, strength of the adhesion between polymer particles and the solid surface was improved over other composite powders.