Antioxidant Activity and Physicochemical Stability of Nanospheres: Evaluation in Vitro and Applied to Biodiesel

Abstract

Abstract Biodiesel is a fuel from renewable sources which has several environmental advantages. However, due to structural characteristics, it becomes susceptible to oxidation, requiring the use of antioxidants. In this way, antioxidants added to biodiesel could be degraded when exposed to environmental conditions, reducing their capacity. Therefore, carrier systems, such as nanospheres, are an alternative to providing protection and controlled release of antioxidants. In this work, poly-ε-caprolactone nanospheres containing tert-butyl-hydroquinone and ascorbic acid antioxidants were developed, and their physical-chemical stability and in vitro antioxidant activity were evaluated for 150 days. The nanospheres to biodiesel were also carried out to evaluate the antioxidant activity. Nanospheres with negative zeta potential, polydispersion index less than 0.3, and nanometric scale were obtained. Regarding the in vitro antioxidant activity, the ascorbic acid nanospheres showed results greater than 50%, while for the tert-butyl-hydroquinone nanospheres, the results were greater than 80% during 150 days. The addition of nanospheres containing antioxidants to biodiesel did not present satisfactory results, since it reduced oxidation stability of biodiesel.