PRODUCTION OF ANOMALOUS POLYMER MICROSPHERES HAVING UNEVEN SURFACES BY STEPWISE HETEROCOAGULATION TECHNIQUE

Anomalous polymer microspheres having uneven surfaces were produced by "stepwise" heterocoagulation technique of small polymer particles (SPs) onto large polymer particles (LPs). SPs and LPs have surface charges opposite to each other in the emulsion states. SPs were produced by emulsion copolymerization of styrene and methacryloyloxyethyltrimethylammonium chloride, and LPs by emulsion terpolymerization of styrene, butyl acrylate and methacrylic acid, with nonionic emulsifier being used in both cases. Maximum covering of LP by SPs was obtained under the conditions that both emulsions were blended without the coagulation at pH 3 at room temperature and then left stand to coagulate with each other at 70 °C for 4 h at pH 9. © 1990 Steinkopff.