Micro-Mechanism Study on the Different Antioxidants Protective Effect of Vegetable Oil by ReaxFF Molecular Dynamics

The aging problem of vegetable oil has severely restricted the popularization and application of vegetable oil transformers. Adding antioxidants is the most recommended solution. At present, there is insufficient research on the micro-mechanism application of the protective effect of antioxidants on vegetable oil. In this paper, multiple vegetable oil models with different types and concentrations of antioxidants are established. Then the molecular dynamics simulation based on ReaxFF is carried out at different temperatures and oxygen content. Results show that the protective mechanism of antioxidants is to release H and combine this with free radicals generated by the decomposition of unsaturated fatty acids (UFA) in the oil. In addition, the protective effects of four antioxidants show different results. The stronger ones are tert-butyl hydroquinone (TBHQ) and butylated hydroxytoluene (BHT), while the weaker ones are butylated hydroxyanisole (BHA) and propyl gallate (PG). TBHQ has a better protective effect at lower concentrations, but the decomposition of UFA is promoted at higher concentrations. When the temperature rises, the decomposition of UFA is promoted. With the addition of oxygen, smaller molecular compounds are easily oxidized, and the decomposition of UFA is accelerated. The above research could reveal the microscopic mechanism of antioxidant protection on vegetable oil, providing theoretical references for further exploration of effective vegetable oil aging protection technology.