两步沉淀聚合法制备表面具有羧基的核-壳微球

Core-Shell Microspheres with Active Carboxyl Groups Prepared by Two-Stage Precipitation Polymerization

以高交联的聚二乙烯基苯-55(poly(DVB-55))为核,甲苯/乙腈(体积比1∶3)混合溶剂,采用两步沉淀聚合法,在核的表面接枝了具有羧基官能团的较低交联度的壳,得到了单分散或窄分散微米尺度的poly(DVB55)/poly(DVB55-co-methacrylic acid)核-壳微球。结果表明,以甲苯/乙腈混合物替代纯乙腈作为反应介质可以获得比表面积、孔容、接枝量和粒径相对较大的核-壳微球;随着poly(DVB-55)核的用量的增加或反应时间的缩短或单体和交联剂投料浓度的减小,所得的核-壳微球的粒径减小、接枝量降低、粘连程度减小,微球的均匀性则升高。

Monodisperse or narrow disperse micrometer core-shell microspheres having active carboxyl groups with a dense core and a lightly crosslinked functional shell were prepared by two-stage precipitation polymerization in toluene/acetonitrile （volume ratio 1：3） mixed solvent. It was showed that core-shell microspheres with relatively large specific surface area, pore volume, graft volume and particle size were obtained by using toluene/acetonitrile mixture alternative to neat acetonitrile as the reaction medium. With increasing the amount of poly （DVB-55） or shortening the reaction time or reducing the amount of monomer and cro^linker, the particle size, the graft and the level of adhesion among particles decrease, while the uniformity of microspheres increases.