二聚酸的合成及其对喷气燃料润滑性的影响

Synthesis of Dimer Acids and Its Effect on the Lubricity of Jet Fuel

以油酸为原料合成了二聚酸,利用红外光谱仪分析其结构,并采用高频往复试验机（HFRR）和球柱润滑性评定仪（BOCLE）分别考察了二聚酸在喷气燃料中的摩擦学性能以及与环烷酸型抗磨剂（T1602）的复配效果,采用SEM扫描电镜及EDS能谱分析试验球片。结果表明,所合成二聚酸具有一定的抗磨效果,二聚酸添加质量分数为80μg/g时,磨斑直径能够达到500μm以内;二聚酸添加质量分数在15~20μg/g范围内即可满足喷气燃料对润滑性的要求;二聚酸与T1602复配后,在二聚酸添加质量分数40μg/g以内时对喷气燃料的润滑性提高不明显,可能由于添加剂在摩擦副表面间存在竞争吸附的原因。二聚酸在摩擦副金属表面发生了化学吸附,形成了具有较好润滑作用的含氧化学保护膜,起到了抗磨效果,同时还伴随着腐蚀效应。

The dimer acid was synthesized with oleic acid as material and characterized by using Infrared spectrometer.Its tribological properties as anti-wear additive in jet fuel and the lubricity effect of the compounded use of dimer acid with naphthenic acid additive T1602 were evaluated by using both the high frequency reciprocating rig（HFRR）and ball-on-cylinder lubricity evaluator（BOCLE）.The morphologies and elemental distribution of the worn steel surface were analyzed by means of scanning electron microscopy and EDS.It is found that the synthesized dimer acid had contribution to the improvement of jet fuel lubricity with its addition above 80μg/g,while the lubricity request of jet fuel was satisfied with the mass fraction of dimer acid in the range of 15-20μg/g.The lubricity effect of compounded additive was not obvious at 40μg/g of dimer acid,due to the competitive adsorption between naphthenic acid and dimer acid.The dimer acid could be adsorbed on the metal surface with strong chemical activity,forming a stable oxygen-containing layer of chemical film to act well anti-wear effect with some corrosive action.