Enhanced photopolymerization rate & conversion of 1-vinylimidazole in the presence of lithium bistriflimide

• Published in: European polymer journal Vol. 60; pp. 92 - 97
• Main Authors: Whitley, John W., Jeffrey Horne, W., Danielsen, Scott P.O., Shannon, Matthew S., Marshall, Jeannie E., Hayward, Spenser H., Gaddis, Christopher J., Bara, Jason E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-11-2014; Elsevier
• Subjects: 1-Vinylimidazole; Applied sciences; Conversion; Equivalence; Exact sciences and technology; Ionic liquids; Lithium; Lithium bis(trifluoromethylsulfonyl)imide; Monomers; Photopolymerization; Physicochemistry of polymers; Poly(vinylimidazole); Polymerization; Polymers and radiations; Radical polymerization; Solubility; Utilities; Poly(vinylimidazole); 1-Vinylimidazole; Lithium bis(trifluoromethylsulfonyl)imide; Photopolymerization; Radical polymerization; Reaction accelerator; Experimental study; Reaction rate; Reaction acceleration; Concentration effect; Imidazole(vinyl) polymer; Lithium compound; Fluorine Organic compounds
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2014.08.015

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•LiTf2N is highly soluble in Vim, producing a coordinated ionic liquid monomer.•Photopolymerization rate & conversion of Vim are greatly improved with LiTf2N.•LiTf2N can be recovered from poly(vinylimidazole) in certain aprotic solvents.•Coordinated ionic liquid monomers eliminate the need for synthetic reactions.
The high solubility of lithium bistriflimide (LiTf2N) in 1-vinylimidazole can be utilized to significantly improve overall monomer conversion and photopolymerization rate. We observed that LiTf2N was miscible with 1-vinylimidazole in stoichiometric equivalence corresponding to a final mixture that is >75% by mass LiTf2N. The rate and conversion of vinyl groups was dynamically monitored using ATR-FTIR. In comparison with the 1-vinylimidazole control, all samples containing LiTf2N exhibited increased monomer conversion and all except the 1:1 sample displayed a more rapid initial reaction rate. The specific effects of the rate and conversion vary with the molar ratio of 1-vinylimidazole to LiTf2N and may be a consequence of coordination complexes between 1-vinylimidazole and the Li+ cation. These results may warrant further investigation into the utility of coordinated, polymerizable ionic liquids that are readily formed from polar organic monomers and LiTf2N.