On the preparation and polymerization of p-methoxystyrene miniemulsions in the presence of excess ytterbium triflate

The cationic polymerization of p-methoxystyrene using an acid initiator and ytterbium triflate as a cocatalyst was studied in miniemulsion. Conductometry measurements revealed that ytterbium triflate dissociates in water. The high ionic strength implemented by ytterbium cation releasing requires the use of an electrosteric surfactant, i.e. sodium dodecylpolyoxyethylene(8) sulfate, as an efficient stabilizer against particle coalescence. The catalyst increases significantly the polymerization rate but only moderately affects the molar masses. A tentative polymerization scheme is proposed based on these results and several other blank experiments.