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Fiber-welded polyionic biocomposites using 1-alkyl-3-vinylimidazolium alkylphosphonate ionic liquids



David Durkin, Christian Hoffman, Anders Gulbrandson, Ethan Fessler, Robert Chung, Tyler Cosby, Paul C. Trulove, Ashlee Aiello, Jeremiah Woodcock


In this study, imidazolium-based polymerizable ionic liquids (Poly-ILs) are used to prepare novel polyionic biocomposites through Natural Fiber Welding. Two new Poly-ILs containing the 1-alkyl-3-vinylimidazolium cation and an alkylphosphonate anion were synthesized and evaluated for their ability to (i) solubilize a biopolymer (cellulose) matrix and (ii) polymerize with and without dissolved cellulose. Raman spectroscopy and scanning electron microscopy (SEM) were used to characterize the fiber-welded composites. Optimized fiber-welding parameters yielded polyionic biocomposite materials whose physicochemical properties were evaluated using SEM, energy dispersive X-ray spectroscopy (EDS) and water sorption testing in a controlled relative humidity chamber. SEM/EDS revealed polymerized Poly-IL integrated throughout a fiber-welded, polyionic biocomposite matrix; the materials absorbed ca. 38-40 % of their mass in water when exposed to a controlled (70%) relative humidity environment. To reduce the hygroscopic nature of the fiber-welded composites, the methylphosphonate anion was partially exchanged for a more hydrophobic anion (bis-trifluorosufonylimide, TFSI) through a single-pass anion exchange. SEM/EDS of sample cross sections before and after treatment show that this simple anion exchange and rinse procedure delivers up to ca. 5% exchange from methylphosphate to TFSI. In spite of this low exchange, the water sorption properties of the exchanged polyionic biocomposites were successfully reduced by nearly 14% and could be easily returned to their original dry state at low temperatures under vacuum.
Journal of Ionic Liquids


polymerizable ionic liquids, biopolymer, anion exchange, natural fiber welding, cellulose


Durkin, D. , Hoffman, C. , Gulbrandson, A. , Fessler, E. , Chung, R. , Cosby, T. , Trulove, P. , Aiello, A. and Woodcock, J. (2022), Fiber-welded polyionic biocomposites using 1-alkyl-3-vinylimidazolium alkylphosphonate ionic liquids, Journal of Ionic Liquids, [online],, (Accessed June 20, 2024)


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Created February 20, 2022, Updated March 10, 2023