分子动力学模拟研究大分子润滑油氧化产物的运动和聚集行为及其对基础油性能的影响

Molecular dynamics simulation on the mobility and aggregation of macromolecular lubricant oxidation products and their influences on base stock

The mobility and aggregation behavior of macromolecular lubricant oxidation products and their influences on the performance of base stock were probed by molecular dynamics (MD) simulation. The mean squrare displacement (MSD) of molecules was calculated to explore the mobility of molecules. The distribution appearance of lubricant oxidation products in models was acquired to explore the aggregation of molecules. The results show that the mobility of macromolecular oxidation products is lower than that of base stock, and the MSD of macromolecular oxidation products reduces with the increasing macromolecular weight. Macromolecular oxidation products can also decrease the mobility of basic oil. The interaction energy between macromolecules and base stock ascends with the increase of macromolecular weight. Macromolecules with larger molecular weight can affect more basic oil molecules with stronger restriction, which leads to lower mobilities of base stock molecules. There are aggregates formed among macromolecular oxidation products, and the molecules in aggregates are connected by hydrogen bonds. The quantity of hydrogen bonds in aggregates is related to temperature.