| Protein is one of the richest renewable resources. Ionic liquids (ILs) are widely used in organic synthesis, electrochemistry, material preparations and analytical chemistry due to their remarkable properties including strong polarity, nonvolatility,nonflammability and high thermal and chemical stability. In our paper, several kinds of imidazolium ionic liquids were synthesised for the dissolution of gelatin. Then the solubility of gelatin in ionic liquids, the changes of original and regenerated gelatin on the struture and properties, and the rheology of gelatin/ionic liquids solutions were investigated. Main contents of this thesis are as follows:(1) Take 1-methyimidazole as the main raw material, several kinds of ionic liquids including 1-allyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium bromide were synthesized. And the compounds were characterized by infrared spectra (FT-IR) and H-1 nuclear magnetic resonance (1H-NMR), whose structures were confirmed.(2) Different ionic liquids (including [AMIM]Cl, [BMIM]Cl, [HMIM]Cl, [BMIM]Br,[BMIM]BF4 and [BMIM]PF6) were used to investigate the relationship of the solubility for gelatin and the structure of ionic liquids. The results indicate that when the cation of the ionic liquids is the same, the chloride anion ionic liquids have better solubility for gelatin than ionic liquids involving other anions; when the anion of the ionic liquids is chloride anion, the ionic liquid involving [AMIM]+ is the most powerful solvent. In addition, the temperature has a strong effect on the solubility. The rate of dissolution increased significantly with the increasing temperature.(3) The regenerated gelatin was obtained from the gelatin/[AMIM]Cl solution by coagulating with methanol or acetonitrile, then the original gelatin and regenerated samples were characterized by XRD, DSC and TGA techniques, respectively, to analyze the changes of crystallinity and thermostability. The results indicate that the regenerated gelatin has lower crystallinity and thermostability. There is also interactions between gelatin and the solvent during the regeneration process. Comparing with acetonitrile, the methanol regenerated gelatin had higher crystallinity and lower thermostability.(4) The rheological behaviors of the gelatin/ionic liquid solutions were investigated by steady shear and oscillatory shear measurements. The effects of concentration and temperature on the rheological properties of the solutions were investigated. In the steady shear measurements, gelatin/ ionic liquids solutions showed shear thinning behavior at a certain frequency and when the concentration increased or the temperature decreased, the critical shear-thinning rate decreased. In the oscillatory shear measurements both the storage modulus and loss modulus increased with the increasing frequency. In the temperature range of 20-50℃, the storage molulus of the gelatin solutions increased with the increase of the concentration, while, when the temperature increased to 60℃or higher, the storage molulus of the solution is essentially independent of polymer concentration, all curves of the solutions overlap with the pure ionic liquid [AMIM]Cl, which strongly suggests an enthalpic origin for the elasticity in the samples. On the other hand, the loss modulus increased with the increase of concentration and decreased with the rising of temperature, which is clearly dependent on the dissolved gelatin. Due to the different behaviors of the storage and loss modulus,, the crossover frequency of them moved to high frequency at high polymer concentration and low temperature.
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