Narrow-disperse, cross-linked polymer microspheres by one-step dispersion polymerization with a chain transfer agent

The increasing demand for monodispersed cross-linked polymers in high-quality applications requires continuous improvement in their preparation process. In this study, an appropriate amount of a chain transfer agent was added to a traditional cross-linking system, resulting in the preparation by one-step dispersion polymerization of cross-linked polystyrene (PS) microspheres with a particle size of 3.867 mu m and a diameter coefficient of variation of 0.011. The particles were characterized using scanning electron microscopy (SEM) and an Ubbelohde viscometer. The results show that the tertiary dodecyl mercaptan (TDDM) chain transfer during nucleation increases the oligomer concentration, promotes the aggregation of the oligomers, increases the primary particle size, and reduces the cross-linking effect. This controls the volume of cross-linked chains in the primary particles, thus avoiding the problem of poor dispersion of the polymer microspheres due to the introduction of divinylbenzene (DVB). This study produces a preparation method for cross-linked microspheres.