Ionic liquids as new solvents of natural polymers

The study conducted led to the following conclusions: - Ionic liquids based on the 1-butyl-3-methylimidazolium cation are not solvents for most synthetic polymers, but dissolve natural polymers characterized by a large number of H bonds in the supramolecular structure up to high concentrations. - The dissolving power of IL based on the 1-butyl-3-methylimidazolium cation is a function of the nature of the anion and the value of the negative charge on its electron-donor sites: IL with an acetate anion dissolve natural polymers better than liquids with a chloride anion. - An increase in the length and number of hydrophobic alkyl radicals in the imidazolium cation increases the hydrophoby of the IL and is accompanied by a decrease in the dissolving power with respect to natural polymers. The charge distribution in the imidazolium cation is a function of the length and number of alkyl radicals, determines the strength of the cation-anion bond, and the dissolving power of the IL changes proportionally to this strength. - Incorporation of proton-donor diluents decreases the dipole moment and value of the negative charge of the IL anion, which results in loss of the dissolving power of the binary mixture. - Aprotic diluents can be incorporated in these IL, and the change in the dissolving power of the binary mixture will be a function of the donor capacity of the aprotic diluent: a smaller decrease in the dissolving power is observed for the binary mixture in which the diluent has a lower donor number and more weakly competes with the IL for formation of hydrogen bonds with the polymer.