胶原蛋白在离子液中的溶解及流变特性

Dissolution and Rheological Behavior of Collagen in Ionic Liquids

摘要:

研究了胶原蛋白在氯化胆碱2ZnCl2离子液体中的溶解性及溶液的稳态流变性能，分别以水、乙醇、乙腈对胶原蛋白进行再生，采用傅里叶—红外光谱（FT-IR）、X射线广角衍射（XRD）、热重示差扫描量热仪（DSC）等对再生胶原蛋白进行结构分析。氯化胆碱?2ZnCl2是胶原蛋白的直接溶剂，120 ℃时胶原蛋白在离子液体中的溶解度可达到11.3 g±0.2 g/100g。红外光谱显示，乙腈再生的胶原蛋白具有完整的三股螺旋结构，但结晶度、热稳定性都较原胶原蛋白样品有所降低。稳态剪切流变分析表明，随着溶液浓度的升高，胶原蛋白/离子液体溶液粘度增大，且随剪切速率的增大，粘度降低，呈现假塑型流体特性；当质量分数为3 g/100g时，溶液呈现显著的剪切变稀现象，且温度达到90 ℃，剪切速率为100 s-1时溶液基本失去粘性。

Abstract:

The solubility and steady-state rheological behavior of collagen in the ionic liquids based on choline chloride?2ZnCl2 were studied. The collagen was regenerated using water, ethanol, and acetonitrile. The structure of regenerated collagen was characterized by Fourier transform infrared spectroscopy (FT-IR), wide angle X-ray diffraction (XRD), thermogravimetry-differential scanning calorimetry (DSC). Choline Chloride?2ZnCl2 was used as the direct solvent for collagen, and the solubility of collagen in the ionic liquid at 120 ℃ was up to 11.3 g ± 0.2 g/100 g. The FT-IR results revealed that the acetonitrile-regenerated collagen had a complete triple helical structure, while the crystallinity and thermal stability of the regenerated collagen were somewhat lower than those of the original sample. The steady-state shear rheological analysis showed that the viscosity of collagen/choline chloride?2ZnCl2 increased with increasing concentrations of solution and decreased with increasing shear rates, which are the characteristic features of a pseudoplastic fluid. When the mass fraction was 3 g/100 g, the shear-thinning phenomenon was observed in solution. Furthermore, the solution viscosity was almost disappeared when the temperature was 90 ℃ and the shear rate was 100 s-1.