Monodisperse micron-sized macroporous poly(styrene-co-divinylbenzene) particles by seeded polymerization

Macroporous poly(styrene-co-divinylbenzene) particles were produced in a micron-size range by two-stage swelling and continuous polymerization. The molecular weight of the polystyrene seed particles was controlled by incorporating a urethane acrylate. It was found that the porosity of the particles produced by the seeded polymerization was dependent on the molecular weight of the seed polymer. As the molecular weight of the polystyrene seed increased, the porous particles produced became macroporous. Interestingly, the high molecular weight of the polystyrene seed had a negligible influence on the change of porosity of the seeded polymerized particles. It is believed that the viscosity of the swollen droplet phase remained pretty high with the change in composition because the polystyrene seed copolymerized with urethane cacrylate had many side chains.