1, 2, 3-Triazole-Incorporated Diacrylate Monomer For Free Radical Cyclopolymerization Through Large Ring Formation

Free radical cyclopolymerization of appropriate bifunctional monomers is an"old"but facile way to afford cyclopolymers with cyclic structures in the polymer backbone. Cyclopolymerization was first observed in 1949 by Butler in the polymerization of diallylammonium salt. Cyclopolymerization is an alternative intramolecular-intermolecular reaction way in which intramolecular reaction is prior to proceed, forming cylic repeat unit in the backbone, then the followed intermolecular reaction give rise to chain propagation.For ideal cyclopolymerization, the extent of cylization is supposed to be 100%, and there is not any detectable residue functional group in the cyclopolymer obtained. The molecular structure of bifunctional monomer is crucial to its cyclopolymerization behavior. Generally, the large pendant group in the monomer and the mutually close functional group pair could favor intramolecular reaction and suppress intermolecular reaction, then increase the cylization. Now in the cyclopolymerization field, the tendency directs to the synthesis of cyclpolymer with large ring.In this work, we designed and synthesized a new structurally optimized diacrylate monomer incorporating 1,2,3-triazole group which was produced by'click chemistry', and studied its cyclopolymeriztion. The research showed that the extent of the cylization for this new monomer in the cyclopolymerization was complete, and the kinetic study indicated it could be applied to living radical cyclopolymeriztion, obtaining well controlled cyclopolymer. The glass transition temperature of the cyclopolymer was determined to be 90oC, which was much higher than conventional linear polyacrylate, this consequence showed that the polymer chain become regid for the sake of the influence of cyclic structure.