SYNTHESIS OF MONODISPERSE POLY(DIVINYLBENZENE) MICROSPHERES

Highly crosslinked monodisperse poly (divinylbenzene) microspheres wer e produced by precipitation polymerization with acetonitrile as solven t. The radical initiators AIBN, BPO, and ADVN were used. The process d oes not require stabilizers of any type, and produces monodisperse par ticles with diameters between 2 and 5 mum, depending on the conditions . These microspheres do not swell or dissolve in any common solvent, a nd have clean, stabilizer-free surfaces. The particle formation and gr owth mechanism is proposed to resemble that of dispersion polymerizati on, except that the particles are stabilized against coagulation by th eir rigid, crosslinked surfaces rather than by added stabilizers. Sphe rical particles were formed only at effective crosslinker/monomer or d ivinyl/monovinyl ratios larger than 1 : 2. (C) 1993 John Wiley & Sons, Inc.