含氰基离子液体的合成、表征及流变性质研究

摘要合成、 表征了一系列新的含氰基咪唑类离子液体. 测定了该离子液体的密度、 熔点及溶解性等物理性质, 研究了其在稳态、 瞬态和动态条件下的流变行为. 结果表明, 当剪切速率在0.1～50 s^-1范围内时, 其粘度不随剪切速率的变化而变化, 但随温度升高而降低, 粘流活化能随取代基长度变化呈现规律性变化. 对于1-丁基-3-氰乙基咪唑六氟磷酸盐离子液体, 维持剪切速率不变时, 其剪切应力和粘度均不随时间变化, 且随着温度的升高而降低; 在动态条件下, 在线性粘弹区, 复合粘度和损耗模量G″ 随温度升高而降低.关键词

Synthesis and Characterization of New Cyno-group Functionalized Ionic Liquids and Their Rheological Properties

A series of cyno-group functionalized ionic liquids were synthesized and characterized by 1H NMR and elemental analysis. The density, melting point and solubility of the ionic liquids were affected by the length of substituted group and the chemical structures of anions. The rheological properties of the ionic liquids under steady, transient and dynamic state were studied with a rheometer over a wide range of temperature and frequencies. It was found that the ionic liquids studied could be considered as Newtonian fluids. Arrhenius equation was employed to describe the relationship between the viscosity and the temperature. The viscous flow activation energy of the ionic liquids calculated was changed regularly with the length change of alkyl substituent. Under transient state condition, the shear stress and viscosity of the ionic liquid 1-butyl-3-(β-propanenitrile) imidazolium hexafluorophosphate, as an example, kept constant with the change of time while the shear speed was fixed. However, a decreasing trend was observed when the temperature was increased. The dynamic rheological properties of this ionic liquid were also studied. The complex viscosity and loss modulus were also decreased with increasing temperature.