有机硼酸酯化纳米纤维素的绿色可控制备及协同润滑机理研究

高效兼绿色已成为润滑添加剂未来发展方向，纳米纤维素作为绿色润滑添加剂的首选材料，其酯化方法尚不环保、摩擦学性能及机理亟需改进。本项目拟运用绿色酯化技术结合元素杂合原理，构制可适用于宽工况环境的有机硼酸酯化纳米纤维素润滑油添加剂-OBN，研究其水解稳定性能、摩擦学性能及物化协同润滑机理。拟采用酸性离子液体绿色溶剂/催化剂体系，同时对纳米纤维素进行亲油改性和硼酸酯化而构制OBN，解析其微观物化结构，形成绿色可控制备方案；评测OBN水解稳定性能，并掌握1-2种水解控制方法；评估OBN摩擦学性能，检验其物化协同润滑作用，明确其适用工况范围，建立“微观物化结构-协同润滑作用”间的构/效关系，提出摩擦学性能优化途径，阐明OBN、摩擦界面、润滑油膜共同在摩擦热力耦合作用下的摩擦微观演变机制，揭示物化协同润滑作用发生机理。本项目将为纳米纤维素在摩擦学领域的应用以及高效绿色润滑添加剂的研制提供技术指导与理论支持。

Lubricant additive is developing towards efficientization and greenization. Nanocellulose has been regarded as the first-choice candidate material for green lubricant additive, but its esterification approaches are still unfriendly to the environment and its tribological performance and mechanism needs to be improved further. In this project, a green esterification technique coupled with the element hybridization theory is adopted to synthesize organic borate-esterified nanocellulose (OBN) lube additive, which can be used under normal and severe working conditions, and studies on hydrolytic stability, tribological properties and physicochemical synergistic lubrication mechanism of OBN will also be conducted. Specifically speaking, nanocellulose will undergo oleophilic modification and borate esterification simultaneously by using acidic ionic liquid as solvent and catalyst, and thus OBN will be synthesized successfully. The physicochemical microstructures of OBN will be analyzed detailedly, and then a green controllable preparation strategy for OBN will be proposed. The hydrolytic stability of OBN will be evaluated, and accordingly several feasible methods to control its hydration will be put forward. Furthermore, the tribological properties of OBN will be investigated systematically to investigate the physicochemical synergistic lubrication effect between BNC’s nanocellulose component and the boric acid ester structure, and define the range of its applicable working conditions. The structure-function relationship between the physicochemical microstructures and the synergistic lubrication effect will be established, and consequently an optimization plan for the tribological performances can be put forward. The tribological physicochemical evolution process of OBN, friction interface and lubricating oil film under the coupling conditions of friction heat and force will be explored and explained, and thus the physicochemical synergistic lubrication mechanism of OBN will be revealed. This project will provide technical and theoretical support for application of nanocellulose in tribology and further development of eco-friendly lubricant additive.