Eco-Friendly Vegetable Oil-Based Metalworking Fluid (MWFs) from Modification of Glycolyzed Products of Polyurethane

In order to produce environmentally friendly and efficient metalworking fluids and also to reduce the impact of waste polyurethane polymer in the environment, polyurethane polymers were recycled in a novel process. Waste polyurethane foam was glycolyzed using polyethylene glycol 400 to give the glycolyzed product (GPU). The GPU was esterified using oleic acid, linoleic acid, and acids obtained from hydrolysis of rapeseeds oil, coconut oil, and castor oil to obtain GPUO, GPUL, GPUA, GPUB, and GPUC, respectively. The prepared additives were used as emulsifiers in the formulation for metalworking fluid application in the presence of rapeseed oil, coconut oil, and castor oil as environmentally friendly oils. The results showed good stability of the prepared water-vegetable oil emulsions. The pH, specific gravity, kinematic viscosity at 40 and 100 °C, surface tension, and anticorrosion tests of the prepared formulation showed acceptable results compared with the published data for several metalworking fluid formulations.