Living cationic polymerization of vinyl ethers

The cationic polymerization of vinyl ethers initiated by CH₃-CH(OR)(I) / R₄N⁺A⁻ (R = Alkyl, A⁻ = ClO₄⁻, BF₄⁻, PF₆⁻, I⁻, NO₃⁻) shows the characteristics of a living polymerization. The rate of polymerization is a function of the solvent polarity, the temperature, the type and concentration of the ammonium salt. The experimental data can be explained on the basis of the secondary salt effect overlapped by some dipol-dipol interactions of the chain end and the added salt. Functionalization of the chain end with thermolabile azo functions yields polymeric initiator which was applied for the synthesis of blockcopolymers. Vinyl ethers functionalized with furylacrylic ester groups were polymerized and crosslinked via [2+2] cycloaddition.