Studies on the Preparation of Stable PSt Latex in the Presence of Cyclodextrins and a Small Amount of Surfactant

Abstract

Polystyrene (PSt) latex was successfully prepared via emulsion polymerization using a novel sequential feeding way. In our method, polymerization was conducted in the presence of betacyclodextrin (b-CD) and a small amount of surfactant. The concentrations of the surfactant, b-CD and initiator, and the including time of St with b-CD acted as crucial roles in the preparing process. The results showed that the coagulum decreased with increasing of the concentration of the surfactant. The coagulum also decreased greatly when the amount of b-CD was lower than 1%. Furthermore, the coagulum decreased at the early stage and then increased with the increase of the concentration of initiator. Also, the monomer conversion increased by increasing the amount of surfactant and initiator. The morphology of the obtained particle was examined with a transmission electron microscope (TEM). The particle size increased constantly with the increase of the amount of b-CD. Otherwise, it decreased with the increase of the concentration of surfactant and initiator. Comparing with the semicontinuous condition, the sequential feeding way improved the monomer conversion, polymerization rate and the monodispersity.