Stabilization of Vegetable Oil-Based Quenchants to Thermal-Oxidative Degradation: Experimental Strategy and Effect of Oxidation on Quenching Performance

Although petroleum oils continue to be the dominant type of basestock for the formulation of vaporizable quenchants, there is increasing pressure to identify an alternative basestock to address the limitations to their continued use because they are not a renewable basestock and they possess generally poor toxicity and biodegradability properties. Currently the most often cited alternative basestocks are those based on seed oils since they are renewable and usually non-toxic but especially because they are typically readily biodegradable. However, they suffer a critically important deficiency in that they are also typically much less stable to thermal-oxidative degradation than petroleum oils. There have been various reports discussing the effect of vegetable oil structure on oxidation and on the use of oxidation inhibitors to provide the necessary stabilization. However, most of these reports do not detail the experimental strategies used to provide this assessment and generally they do not address the relative effects of specific antioxidant structures on inhibiting oxidation and on quenching performance. This paper will address the experimental strategies used to determine the optimal antioxidant structure and concentration on properties and thermal-oxidative stability of seed oil derived quenchants and the effect of oxidation on quenching performance