分散剂对润滑油氧化产物聚集影响的分子动力学模拟

采用分子动力学（MD）模拟方法研究了润滑油氧化产生的极性小分子的聚集行为以及分散剂聚异丁烯琥珀酰亚胺对其聚集的影响。研究发现：随着模拟时间的增长，润滑油氧化产物分子通过氢键形成了分子聚集体；在不含分散剂的润滑油中，形成聚集体的分子个数不断增加，润滑油氧化产物分子在晶胞中的分布不断集中；在含有分散剂的润滑油中，润滑油氧化产物分子之间仍可以形成2~3个分子组成的小聚集体，但是没有出现由多个分子形成的大聚集体，润滑油氧化产物分子仍然相对均匀地分散在晶胞中；分散剂通过对润滑油氧化产物分子形成空间阻隔以及与润滑油氧化产物分子之间形成更加稳定的氢键两方面的作用，阻碍其形成大聚集体。

Molecular Dynamics Simulation on the Effect of Dispersants on the Aggregation of Lubricant Oxidantion Products

Molecular dynamics simulation method was used to study the aggregation of the molecules of lubricant oxidation products and the effect of dispersants, polyisobutylene succinimide, on the aggregation. The results show that aggregates are formed between molecules of lubricant oxidation products by hydrogen bonds with the increases of the simulation time. The number of molecules in the aggregates increases over time in the lubricant without dispersants and the distribution of lubricant oxidation products molecules in the cell is concentrated. Aggregates consist of 2-3 molecules are still formed in the lubricant with dispersants. However, large aggregates made up of multiple molecules will not be formed over time, and the molecules of lubricant oxidation products are still relatively homogeneously dispersed in the cell in the later period. Dispersants could prevent the formation of large aggregates by space barrier and forming more stable hydrogen bonds between dispersants and molecules of lubricant oxidation products.