Authors Pfukwa, H. ; Coetzee, C. ; Johani, J. ; Carstens, A. ; Lederer, A. ; Pasch, H.
Title Aldehyde-functionalized polymers from the reverse iodine transfer polymerization of lignin-derivable compounds
Date 15.10.2021
Number 59730
Abstract Renewable polymers with reactive functionalities become increasingly attractive as they address some critical global concerns related to sustainability. In this work, vanillin methacrylate (VM), an aldehyde-functionalized monomer synthesized by the methacrylation of vanillin (a possible lignin derivative), was polymerized for the first time via reverse iodine transfer polymerization. The influence of various reaction parameters including the polymerization solvent, the initiator-to-iodine ratio, and the polymerization temperature on the induction (or inhibition) period and the molar mass was investigated by 1H NMR spectroscopy and size exclusion chromatography. The lack of a clear and consistent discoloration of the reaction mixture to indicate the end of the induction period in the solvents investigated, i.e., toluene, methyl ethyl ketone (MEK), and N,N-dimethylformamide (DMF), was an indication that iodine was taking part in a side (complexation) reaction with the solvent. When the monomer conversions were followed by 1H NMR spectroscopy, it was found that the induction periods for the reactions carried out in MEK and DMF were significantly shorter due to the consumption of iodine by VM, leading to the formation of a chain transfer agent (CTA), 4-formyl-2-methoxyphenyl-2-iodo-2-methylpropanoate. The formation of polymer chains derived from this CTA was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. To demonstrate the “livingness” of the polymerization process, PVM was chain-extended with methyl methacrylate, and the formation of block copolymers was confirmed by high-performance liquid chromatography. The application toolbox of these polymers was expanded by the formation of various poly(vanillin methacrylate) Schiff base polymers endowed with additional functional groups.
Publisher ACS Applied Polymer Materials
Citation ACS Applied Polymer Materials 3 (2021) 3941-3952

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