凝胶渗透色谱法测定基础油PAO的相对分子质量及分布

聚α-烯烃是一种性能优良的润滑油基础油，其相对分子质量及分布直接影响宏观性能。本研究建立了一种用于表征1-癸烯齐聚物相对分子质量及分布的方法。采用带示差折光检测器的凝胶渗透色谱系统，综合考虑分离效果和测试可操作性，优化了流动相流速和凝胶色谱柱的组合方式。以四氢呋喃为流动相，流速为0.8 mL/min，色谱柱组合方式为Styragel HR 0.5,Styragel HR 1,PLGEL 3μm MIXED-E三柱串联，以聚苯乙烯作为标准样品，采用普适校正方法处理色谱流出曲线。此方法测得样品的质均相对分子质量与凝胶渗透色谱-光散射法所测定结果相比较，相对误差相对偏差在3%以内。

RELATIVE MOLECULAR MASS AND DISTRIBUTION OF PAO WITH GEL PERMEATION CHROMATOGRAPHY

Poly-alpha-olefin (PAO) is a kind of high-quality based oil of synthetic lubricants. Its relative molecular mass and distribution directly affect macroscopic properties. A method was developed for characterizing the relative molecular mass and distribution of 1-decene oligomer. Gel permeation chromatograph (GPC) equipped with differential refractive index (RI) was used to characterize the relative molecular mass and distribution of PAO. The operation conditions of GPC-RI were optimized, including the flow rate of the mobile phase and the combination of gel chromatographic columns to optimize the separation effect and operability. The operation mode was that the tetrahydrofuran as flow phase with a flow rate of 0.8 mL/min, combination of three columns of Styragel HR0.5, Styragel HR1, and PLGEL 3μm MIXED-E in series to separate PAO. The chromatographic efflux curve was processed by universal calibration method with polystyrene (PS) as the standard sample. Compared with GPC-LLs, the relative deviation for weight average relative molecular mass measures was less than 3%.