Preparation and Characterization of Oil-Dosed Phases Created by Supercritical Fluid on Polymer Materials

Ultra-high molecular weight polyethylene (UHMWPE) and polyamide 66 (PA66) were used as model polymers in order to conduct research on the preparation and characterization of oil-dosed phases created by supercritical fluid on polymer materials. As lubricating oil impregnates polymer material, diethylhexyl adipate (DEHA = DOA, Mw = 370) and alkyldiphenylether (ADE, Mw = 440) were used. Oil impregnation conditions were controlled to between 60 °C and 150 °C and 10–20MPa in Supercritical carbon dioxide (scCO₂) environment. Experimental results showed that the total amount of oil impregnation correlated with processing temperature and duration. After impregnation, phases with a crystal structure different from the inside were observed on the polymer surface areas. The depth profile and chemical-distribution of oil-dosed phases by scCO₂ impregnation were analyzed using Fourier-transform infrared (FTIR) spectroscopy. FTIR spectroscopy results have shown that it is possible to create phases having high concentrations of lubricating oil at a depth of about 25–30 micrometers from the surface of polymer materials.