Polymer microspheres with active carboxyl groups: preparation, structure and hydrophilicity.
ABSTRACT A quantitative research of microspheres, poly(ethylene glycol dimethacrylate-co-acrylic acid) (P(EGDMA-co-AA)) and poly(divinvlbenzene-80-co-acrylic acid) (P(DVB-co-AA)), with active carboxyl groups on surface prepared by distillation-precipitation polymerization was presented in this paper. The loading capacity of active carboxyl group on microspheres which was investigated by titration technique would be increased and the contact angle was decreased following the increase of the feed ratio of acrylic acid (AA) monomer. This phenomenon indicated that the hydrophilicity of particles was mainly determined by the feed ration of hydrophilic AA monomer. However, when the AA fraction was at a fixed level, a slight difference of the loading capacity of carboxyl groups on microsphere surfaces with different crosslinkers existed. The microspheres with EGDMA as crosslinker had a higher loading capacity of carboxyl groups and lower contact angle than those of P(DVB-co-AA) microspheres, which indicated that P(EGDMA-co-AA) microspheres were more hydrophilic than P(DVB-co-AA) microspheres.