Comparison of dissolution and regeneration structure of collagen with two ionic liquids: [BMIM]Cl and [BMIM]Ac

1-butyl-3-methylimidazolium acetate([BMIM]Ac) was synthesized from 1-butyl-3-methylimidazolium chloride([BMIM]Cl) via the ion exchange method. These imidazolium ionic liquids(ILs) were used as solvents to dissolve collagen fibers. The solubility and the change of collagen structure as well as thermal stability after dissolution and regeneration from ILs were investigated. Athough collagen fibers could be dissolved in both CH3COO- and Cl- imidazolium ionic liquids, the dissolution characteristics were quite different. Compared with [BMIM]Cl ionic liquid, [BMIM]Ac was more advantageous to achieve a collagen solution with high concentration and good fluidity at a lower temperature, especially in retaining the integrity of collagen triple helix. FTIR, UV, XRD, CD and TG analysis were used to characterize the structure and properties of collagen before and after regeneration, and the results revealed that collagen chemical structure showed almost no change, but with slightly lower thermal stability and integrity of triple helix.