GRAFT-COPOLYMERS HAVING HYDROPHOBIC BACKBONE AND HYDROPHILIC BRANCHES.10. PREPARATION AND PROPERTIES OF WATER-DISPERSIBLE POLYANIONIC MICROSPHERES HAVING POLY(METHACRYLIC ACID) BRANCHES ON THEIR SURFACES

The free radical copolymerization of poly(t-butyl methacrylate) (PBMA) macromonomer with styrene in ethanol give monodispersed microspheres with 0.8-1.6 mu m diameter. The resulting microspheres were treated wi th HC1 solution to convert into anionic microspheres having poly(metha crylic acid) chains. ESCA analysis of the microsphere surface suggeste d that PBMA chains were favorably located on the surface of the micros pheres. The particle size of the microspheres decreased with increasin g molecular weight and concentration of the macromonomer. Water disper sibilities of the microspheres were evaluated by measuring the relativ e turbidity of the suspension of microspheres as a function of pH. The results show that they were strongly dependent on pH. (C) 1995 John W iley and Sons, Inc.