Photoinitiated cationic polymerization of mono and divinyl ethers in aqueous medium using ytterbium triflate as lewis acid

Photoinitiated cationic polymerization of vinyl ethers in aqueous medium by using diphe-nyliodonium iodide (DPII) in the presence of a water-tolerant Lewis acid, ytterbium triflate (Yb(OTf)₃), was reported. The polymerizations were performed in heterogeneous systems consisting of an aqueous phase containing Yb(OTf)₃ and photoinitiator and an organic phase of acetonitrile containing monomer. The polymerization consists of two-steps; (i) photoin-duced adduct formation and (ii) subsequent propagation with the aid of Yb(OTf)₃. The fast polymerization exhibited an explosive character so that the monomer conversion and molecular weights of the resulting polymers are very dependent on the experimental conditions, such as temperature, stirring manner and rate.