Abstract

Poly-α-olefins and polyesters are the base stocks for the production of synthetic oils, and after mixing with mineral oils for semi-synthetic oils. Their behaviour at the temperatures found in a car engine at work (around 140 °C) is very important. The authors propose the use of an inverse gas chromatography (IGC) technique for qualification of their mixing properties.

Information on the basic parameters for SN-200 oil (H-6), poly-α-olefin (PAO-6), ester (DB-51) and their mixtures H-6–PAO-6, H-6–DB-51 was obtained from standard, normalised methods.

All examined base oils and their mixtures were placed in gas chromatographic columns and act as liquid stationary phases in the chromatographic process. The Flory–Huggins parameter χ^∞₁₂ was calculated from the retention data (IGC) for selected test solutes. For the mixtures H-6–PAO-6, H-6–DB-51 the values of Flory–Huggins parameter χ^∞_1(2,3) were calculated.

The interactions between components of investigated mixtures were expressed by the Flory–Huggins interaction parameter χ^∞₂₃.