Influence of nanoparticles dispersion in POE oils on lubricity and R134a solubility

Nanotechnologies offer the opportunity to improve the characteristics of the oil and the oil–refrigerant mixture in refrigeration and air conditioning equipments by dispersing nanoparticles in the oil. Here a study of the influence of the dispersion of single wall carbon nanohorns (SWCNH) and titanium dioxide (TiO2) on the tribological properties of a commercial POE oil is presented, together with the effects on the solubility of R134a at different temperatures. The results obtained showed that the tribological behaviour of the base lubricant here considered can be either improved or worsen, depending on the property (anti-wear or extreme-pressure behaviour), by adding small amount of nanoparticles. On the other hand, nanoparticles dispersion in the base oil did not affect significantly the solubility, suggesting the independence of the thermodynamic properties of the oil from the presence of nanoparticles.