Synthesis of monodisperse porous poly(divinylbenzene) microspheres by distillation-precipitation polymerization

Highly crosslinked monodisperse porous poly(divinylbenzene) (PDVB) microspheres were prepared by distillation-precipitation polymerization in acetonitrile containing up to 25 vol% of toluene as porogen with 2,2′-azobisisobutyronitrile (AIBN) as initiator in the absence of any stabilizer or surfactant. The porous polymer microspheres were formed through a precipitation manner during the distillation of the solvent from the reaction system. Monodisperse porous polymer particles with spherical shape and smooth surface were synthesized with diameters in the range of 1.86 and 3.06 μm, total porosity of up to 0.30 cm3/g and specific surface area as high as 762 m2/g. The growth procedure of porous PDVB microsphere was characterized by SEM technique for morphological observation and isotherm nitrogen adsorption for the determination of the special surface area and porosity. The resultant porous polymer microspheres had a novel structure with the gradual increasing of pore volume during distillation of the solvent out of the reaction system.