Abstract: Monodispersed polystyrene microspheres with three distinct dyes and carboxyl group in the size range of 400—800 nm were prepared with seed polymerization and swelling, which affords a new method to combine the dyes with the microspheres. Monodispersed polystyrene seed was produced via emulsifier-free emulsion polymerization. It was swollen first by di-n-butyl phthalate(DBP), then by the mixture of styrene(St)-acrylic acid(AA)-divinylbenzene(DVB)-dyes including an oil-soluble initiator. The final microspheres were obtained via the polymerization of monomer mixture in the swollen seed microspheres at 70 ℃. The average size, size distribution and surface morphology of the final beads were characterized via SEM. The effects of the quantity of DBP, monomer and monomer proportion on the size distribution and surface morphology were discussed.

Key words: Colour microphere, Monodisperse, Two-step swelling, Seed polymerization