Monodisperse, full-IPN structured polymer particles in micron-sized range by seeded polymerization

Monodisperse micron-sized poly(styrene/divinylbenzene) particles of an interpenetrated polymer network (IPN) were produced by the seeded polymerization in the presence of slightly crosslinked polystyrene seed particles. In order to evaluate the two-stage swelling of the monomer emulsion in the case of utilizing the crosslinked seed particles, a thermodynamic equation was proposed with the crosslinking degree of the seed particles and the droplet size of the second monomer emulsion (styrene and divinylbenzene). In the light of thermodynamics, it was elucidated that an effective diffusion of monomers during swelling could be achieved in the conditions of lower crosslinking degree of the seed particles and smaller droplet size of monomer emulsions than that of seed particles. After the polymerization, the poly(styrene/divinylbenzene) particles having full-IPN structure were obtained around 5 μm, consequently displaying a good thermal stability.