Metal-free photoinitiated controlled cationic polymerization of isopropyl vinyl ether using diaryliodonium salts†
A photoinitiating system for controlled cationic polymerization of isopropyl vinyl ether (IPVE) was developed using diaryliodonium salts as the photoinitiator. UV irradiation triggered the degradation of diphenyliodonium iodide, which was followed by the controlled polymerization of IPVE mediated by long-lived propagating species. Polymerization was most likely initiated via the generation of hydrogen iodide through photodegradation of the initiator. The propagation reactions then proceeded via the spontaneous cleavage of carbon–iodine bonds in the initiating and propagating chain ends. In addition, other photoinitiators that do not possess an iodide anion as a counteranion induced long-lived-species-mediated cationic polymerization of IPVE when combined with a tetraalkylammonium iodide.