Effect of Coagulation Bath Conditions on the Properties of Cellulose Packaging Films From Ionic Liquid [BMIM]Cl

By using natural softwood pulp with higher degree of polymerization (DP=1460)as cellulose source and 1-butyl-3-methylimidazolium chloride([BMIM]Cl)ionic liquid as solvent, a novel cellulose packaging film was prepared. The effects of coagulation types, concentration of coagulation and temperature on the structure, mechanical property, permeability for oxygen and water vapor were measured. The investigations suggest that the coagulation bath has great effect on the morphologies of the films, and the films prepared in [BMIM]Cl/water coagulation media show denser structure than those prepared in water, C2H5OH and DMSO media. When the [BMIM]Cl concentration in the coagulation bath increases, the tensile strength increases at first and then decreases. With increasing temperature of the coagulation bath, the tensile strength decreases slowly while the elongation at break of the films increases at first and then decreases. It was also found that both the oxygen permeability and the water vapor permeability of the films increase with the temperature of coagulation bath and the concentration of [BMIM]Cl in the coagulation bath. The films prepared by using ionic liquid technology would be used in food packaging or other fields as a kind of green packaging material.