Influence of the kind of end groups of polysterene on the production of hollow particles by suspension polymerization for divinylbenzene/toluene droplets dissolving them

Suspension polymerizations for divinylbenzene (DVB)/toluene droplets dissol ving polystyrene (PS) having different end groups were carried out. Hollow polymer particles were not obtained with PS having polar sulfate end groups , which were prepared by emulsifier-free emulsion polymerization with potas sium persulfate initiator. On the other hand, they were obtained with PS ha ving low polarity isobutyronitrile end groups, which were prepared by solut ion polymerization with 2,2'-azo-bis(isobutyronitrile) initiator. The inter facial tensions between the water and xylene/toluene (1/1, w/w) mixture sol ution of PS having polar groups was smaller than that having low polarity g roups. From these results, it is concluded that the preferential adsorption of PDVB molecules formed by the suspension polymerization at the interface of the droplets over PS molecules, which depended on the kind of the end g roups, is one of the key factors for the formation of the hollow structure.