Fundamental Insights into Free-Radical Polymerization in the Presence of Catechols and Catechol-Functionalized Monomers
Nerea Jiménez, Fernando Ruipérez, Estíbaliz González de San Román, José M. Asúa, Nicholas Ballard
Abstract
Polymers containing catechols are attractive for use in a diverse range of applications. However, the direct incorporation of catechols is challenging in polymers produced by radical polymerization due to transfer and termination reactions that readily occur between catechols and radical species. In this work, it is demonstrated that while monosubstituted olefins such as styrene and methyl acrylate readily undergo chain transfer to phenolic hydrogens, methacrylic monomers do not suffer any inhibitory activity and can be polymerized to high molecular weights without any influence of the catechol, even when the catechol is present in large amounts (50 wt %). In addition, it is demonstrated that even for the polymerization of monosubstituted olefins, the inhibitory activity of catechols can be substantially reduced by the selection of polar solvents such as dimethyl formamide. Thus, through appropriate selection of monomers and reaction conditions, it is shown that catechol-containing monomers can be readily incorporated into polymers obtained by free radical polymerization without any protection/deprotection of the catechol.