2002 Annual Report
Research
Use of Vegetable Oils in Metalworking Fluid Formulations
Peter Raynor, Assistant Professor, Environmental Health
Mrinal Bhattacharya, Professor
Funding Source
USDA, National Research Initiative
Objective
The objective of this research is to formulate a vegetable oil-in-water
emulsion that performs well as a metalworking fluid and decreases substantially
the amount of mist generated during machining. In addition, this emulsion
will be readily biodegradable.
Project Description
The machining industry is large. The National Institute for Occupational
Safety and Health (NIOSH) has estimated that more than 1.2 million people
in the United States work with or near metalworking fluids. Metalworking
fluids pose potential health hazards for machinists and other workers.
NIOSH (1998) has recommended that permissible exposure limits for metalworking
fluid mists be lowered from 5 mg/m3 to 0.5 mg/m3. Although metalworking
fluid mist concentrations currently rarely tops 5 mg/m3, significant reductions
in mist concentration would be required at many facilities to consistently
fall below the 0.5 mg/m3 limit. Thus, finding methods to reduce worker
exposures to metalworking fluid mists is an important pursuit.
Results
Emulsions of vegetable oils were prepared using ionic and non-ionic surfactants for use as metal working fluids. The conditions for an enhanced mutual miscibility for soybean oil or modified soybean oil and water were investigated to prepare emulsions for vegetable oil-based components. Oil modification was achieved using ozonation and sulfurization reactions. The products were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The viscosities of the modified oil were considerably higher than the starting oil. The emulsions were obtained with the aid of three different surface-active agents at room temperature. The stability and efficiency of these emulsions were evaluated. These emulsions also showed good stability and anticorrosion properties. The phase behavior was evaluated using phase diagrams. Cryo-Scanning Electron Microscope (SEM) was used in describing the oil-water interaction during the emulsion formation. It was found that the phase behavior was dependent on the nature and the concentration of surfactant used. Modified oils required comparatively increased amounts of surfactant than the regular oil to obtain a stable emulsion. The prepared emulsions showed properties comparable to that of the petroleum-based formulations.