Living/Controlled Polymerization of Renewable Lignin-Based Monomers by Lewis Pairs

It is a challenging task to replace the traditional petroleum-based monomers with the biorenewable monomers for polymer synthesis, as it can alleviate the energy and environmental crises. Lewis pairs (LP) composed of organophosphorus superbases and organoaluminum Lewis acid are employed to rapidly and quantitatively transform a series of biorenewable monomers derived from the lignin degradation products into polymers with predicted molecular weight (M-n up to 519 kg mol(-1)) and small D value (as low as 1.10). The livingness of the polymerization of lignin-based monomer by such LP system can be also verified by the following evidence, including a linear increase of polymer M-n vs monomer-to-initiator ratio and monomer conversion and high end-group fidelity as evidenced by successful chain extensions and synthesis of well-defined block copolymers. More impressively, the lignin-based copolymers with methyl ferulate exhibited fluorescence response under the irradiation of UV light at 365 nm, suggesting application potential of the lignin-based polymers in biological imaging, information storage, and anti-counterfeiting materials.