摘要
以低黏度聚α-烯烃基础油为研究对象,采用高压反应釜在150~200℃下对其氧化240 h,采用柱层析分离工艺结合GC-MS分析,研究聚α-烯烃基础油长时间氧化过程中分子组成与结构的变化特性,分析结构演变与性能衰变的关系,探讨聚α-烯烃基础油氧化衰变机制。研究结果表明:高温下聚α-烯烃基础油发生热分解反应和热氧化反应,其中长时间氧化以热氧化反应为主;高温氧化导致聚α-烯烃黏度降低、酸值增大、颜色变深,其中在200℃下氧化后其运动黏度(40℃)由18.961 mm^(2)/s降至18.469 mm^(2)/s,酸值由0.011 mg/g增至0.132 mg/g;聚α-烯烃热分解发生无规则断链、解聚和支链脱除,产生小分子烃类、支链烃等低分子物质,导致黏度衰变;聚α-烯烃热氧化产生的具有未酯化羧基的芳酸酯,是导致其酸值增加的主要原因,氧化产生的具有n-π^(*)结构的含氧化合物,导致其颜色变深。
The low viscosity poly-α-olefin based oil was oxidized for 240 h at temperatures ranging from 150℃to 200℃in a high-pressure reactor.A combination of column chromatography separation technique and gas chromatography-mass spectrometry(GC-MS)was employed to analyze the changes in molecular composition and structure during the oxidation process.The relationship between structure evolution and performance degradation was analyzed to explore the oxidation and degradation mechanism of PAO base oil.The results show that under high-temperature conditions,the PAO base oil undergoes thermal decomposition and thermal oxidation reactions,with thermal oxidation being the dominant reaction during prolonged oxidation.High-temperature oxidation leads to a decrease in viscosity,an increase in acid value,and darkening of color.Specifically,after oxidation at 200℃,the acid value of the PAO increases significantly from 0.011 mg/g to 0.132 mg/g,and the kinematic viscosity at 40℃decreases from 18.961 mm^(2)/s to 18.469 mm^(2)/s.The thermal decomposition of PAO results in random chain cleavage,depolymerization,and removal of side chains,producing low-molecular-weight substances such as small hydrocarbons and branched hydrocarbons,which contribute to viscosity degradation.The increase in acid value is primarily attributed to the formation of aromatic esters with unesterified carboxyl groups during thermal oxidation.Additionally,the presence of n-π^(*) structure-containing oxygenated compounds generated during oxidation leads to the darkening of the oil′s color.
作者
徐茹婷
赵剑
文世涛
孙康
卢辛成
张燕萍
蒋剑春
XU Ruting;ZHAO Jian;WEN Shitao;SUN Kang;LU Xincheng;ZHANG Yanping;JIANG Jianchun(Institute of Chemical Industry of Forest Products of Chinese Academy of Forestry,Key Lab of Biomass Energy and Material of Jiangsu Province,Key Lab of Chemical Engineering of Forest Products of National Forestry and Grassland Administration,National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass,Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources,Nanjing Jiangsu 210042,China)
出处
《润滑与密封》
北大核心
2025年第9期41-49,共9页
Lubrication Engineering
基金
国家重点研发计划项目(2023YFD2201604)。
关键词
聚α-烯烃基础油
氧化衰变特性
热氧化
热分解
黏度衰变
poly-α-olefin based oil
oxidation decay characteristic
thermal oxidation
thermal decomposition
viscosity decay
