A study of the oxidation and wear properties of vegetable oils: Soybean oil without additives

Abstract

The use of biodegradable lubricants in diverse applications continues to increase. Vegetable oils (e.g., soybean oil) are the main biodegradable lubricant base stocks used worldwide. However, there are concerns about their oxidative stability and low-temperature performance. Improvements in oxidative stability can be made through chemical or genetic modifications. This work compared the effects of oils with different chemical compositions. Soybean oil, high-oleic soybean oil, and epoxidized soybean oil were compared in laboratory bench tests. The tests conducted include the Penn State sequential four-ball wear test and the Penn State micro-oxidation test. Oxidation products from the micro-oxidation test were analyzed by FTIR and gel permeation chromatography. In this paper, all oils were evaluated neat, without additives.It is only natural that lubricant technology has advanced as a result of concerns for protecting and preserving the environment in all aspects of our lives. Research and development in lubricant technology to find better ways to protect the environment-or at least to reduce environmental pollutants-is driven by public demand, industry concerns, and governmental agency policies. The negative impact of the spillage or leakage of lubricants has led to the development of oils and greases that are less detrimental to the environment if inadvertently spilled or leaked.As a result of these growing environmental concerns, vegetable oils and their derivatives are finding their way into lubricants used in industrial and transportation applications. Vegetable oils can offer significant environmental advantages with respect to biodegradability and renewability, as well as satisfactory performance in a variety of applications. However, vegetable oils differ from traditional mineral or synthetic oils in that they are composed of TAG, which have different amounts and types of FA attached to the glycerol portion of the vegetable oil structure. The FA vary in the length of their hydrocarbon chains and degree of unsaturation (1). A direct consequence of this unique composition is that such oils oxidize much more rapidly than other lubricant base fluids because of the presence of double bonds. As a result, improving the oxidative stability of vegetable oils is a major objective. One approach used to improve their performance is to modify the FA structure either chemically or genetically (2).In this study, the oxidative and wear performance of oils were compared to better understand how the chemical composition of the base stock affects these properties. The oxidative stability of the base oils can be evaluated by different techniques. In this study, the Penn State micro-oxidation test (PSMO), a thin-film test used extensively to study the oxidative stability of mineral and synthetic oils, was selected. This relatively simple thin-film test requires a much smaller sample size than most oxidation tests; it is not oxygen-diffusion limited and requires relatively short test durations (3,4). The wear performance of the ...

Chemical/Structural Modification of Canola Oil and Canola Biodiesel: Kinetic Studies and Biodegradability of the Alkoxides

“…PP of the PCBB satisfies (−7 • C) the ISO VG32, VG 46, VG 68, VG 100 (−6 • C) lubricant requirement. The relative excellent PP of the alkoxides derivatives is attributed to hydrogen bonding of the hydroxyl group present in the alkoxylation products [21]. From this study, it was also noticed that alkoxylation with secondary alcohol (2-propanol, −21 • C) is more favorable to lower PP than tertiary alcohol (TBA, −7 • C).…”

Effect of irrigation intervals and fertilizers on chemical composition, minerals and fatty acids of safflower (Carthamus Tinctorius L.) seed

“…An increase in the period of storage significantly (P < 0.05) promoted the oxidation process and resulted in a higher evaporation loss owing to the formation of volatile products (peroxides, alcohols, aldehydes, ketones) from the breakdown of the fatty acid chain. Evaporation loss increased at higher temperatures because of the increased oxidation rate, which led to higher fragmentation and decomposition (Castro et al, 2006). …”

Green waxes, adhesives and lubricants

“…One of the several ways to reduce unsaturation is to partially hydrogenate (Dehault & Demoulin 1984;King et al 2001) these vegetable oils to improve their service lives without affecting the freezing points to a large extent. Epoxidation (Adhvaryu et al 2004;Castro et al 2006;Fox & Stachowiak 2007; R e t r a c t e d Additionally, neat vegetable oils also pose some problems when subjected to extended use in internal combustion engines. These problems are attributed to high viscosity, low volatility and polyunsaturated character of neat vegetable oils, which could be substantially reduced by conducting chemical modifications to the carboxyl group in TAG molecules of vegetable oils.…”