The efficient cyclopolymerization of silyl-tethered styrenic difunctional monomers

The synthesis and characterization of innovative difunctional styrene-based monomers and their cyclopolymerization is reported. Difunctional silyl-based protecting groups with different steric hindrance (either methyl/phenyl or phenyl/phenyl) are used as tethers for two 4-vinylbenzyl reactive moieties. We demonstrate that efficient cyclopolymerization, performed under free-radical conditions or RAFT-mediated, takes place for both monomers. RAFT polymerization allows excellent control of M-n and higher degree of polymerization when compared to uncontrolled radical polymerization, yet not optimal control of dispersities. The silyl tethering group could be removed to afford poly(p-hydroxymethylstyrene). Thermogravimetric analysis (TGA) demonstrates the thermal robustness of the new cyclopolymers, and gives an insight on the ability of the corresponding deprotected polymer to chelate metals ions. The described strategy opens possibilities to achieve sequence control through a cyclopolymerization/tether removal strategy, when having two suitable aromatic systems with opposing electronic character and reactivities in chain cyclopolymerization. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1593-1599