胆碱杂环二酸离子液体水润滑添加剂的制备及结构-性能关系研究

以胆碱和杂环二酸为原料，在去离子水中原位制备了添加剂Ch]₂Hdc]，并研究了它们的摩擦学性能、腐蚀性、水生生物毒性与分子结构之间的构效关系. 研究发现，水溶液的运动黏度随着水中生成的Ch]₂Hdc]浓度的增加而增大，并且当Ch]₂Hdc]的分子结构对称性较低、极性较大时，水的黏度增加值相对较大. 这是由于添加剂分子极性较大时，分子间相互作用力较大，导致溶液的黏度增幅更大. 摩擦学性能测试发现，当Ch]₂Hdc]的浓度相对较低时，水溶液的减摩抗磨性能与Ch]₂Hdc]分子在摩擦副表面的吸附能力有关，分子极性较大，吸附能力较强的Ch]₂Hdc]可在摩擦副表面形成更为牢固的润滑保护膜，因而能有效改善水的减摩抗磨性能，反之则不能. 当Ch]₂Hdc]的浓度相对较高时，水溶液的减摩性能与其黏度呈反相关关系，抗磨性能则与其黏度呈正相关关系. 这是由于润滑剂黏度相对较大时，其内摩擦力较大，因而表现出较高的摩擦系数，即较差的减摩性能；然而，黏度相对较大的润滑剂则可以在摩擦副表面形成更为牢固的润滑保护膜，因而表现出较低的磨损体积，即较好的抗磨性能. 腐蚀试验结果表明，Ch]₂Hdc]可显著降低水对金属基底材料的腐蚀性. 毒性试验显示Ch]₂Hdc]对绿藻和海虾毒性远远小于传统离子液体L-B104. 

Preparation and Structure-Performance Relationship of Choline Heterocyclic Dicarboxylate Ionic Liquid lubricants

Lubricating additives Ch]₂Hdc] were synthesized in situ by a reaction between choline and heterocyclic dicarboxylic acids in water. The structure-activity relationship between the performance, tribological property, corrosion performance, aquatic toxicity, and the additives molecular framework were investigated. The results showed that the kinematic viscosity of the aqueous solution increased as the raising of the additive (Ch]₂Hdc]) concentration. Moreover, when the molecular structure of Ch]₂Hdc] had low symmetry and high polarity, the viscosity increase was relatively large. This was due to that, when the additive molecule had higher polarity, the intermolecular interaction was greater, and it led to the larger viscosity of the solution. The tribological test results showed that the friction-reducing and anti-wear performance of the aqueous solution was related to the adsorption capacity of Ch]₂Hdc] molecular on the metal surface of the friction pairs. Effective lubricating protective films formed by the Ch]₂Hdc] which had higher polarity and strong adsorption capacity. When the concentration of the Ch]₂Hdc] was relatively high, the friction-reducing performance of the aqueous solution was inversely related to its viscosity, and the anti-wear performance was positively related to its viscosity. It was because that the lubricant viscosity was higher, the internal friction of the lubricant was larger. As a result, it showed a higher friction coefficient, i.e. poor friction reducing performance. The results of corrosion experiments showed that the corrosion of water was reduced obviously by Ch]₂Hdc]. The results of toxicity tests showed that the toxicities of Ch]₂Hdc] to green algae and sea shrimp were much less than traditional ionic liquid L-B104.