Stabilization of PE with the natural antioxidant t-resveratrol: Interaction of the primary and the secondary antioxidant

The study focuses on the possibility of using resveratrol, a stilbenoid-type natural antioxidant, as a stabilizer in polyethylene. The experiments were carried out in two stages. First, the efficiency of the natural antioxidant was compared to that of a commercial product, and then polymer properties were determined as a function of additive content. Stabilization efficiency was determined by multiple extrusion experiments. Resveratrol proved a very efficient stabilizer, more efficient than the commercial hindered phenolic antioxidant. Resveratrol provides excellent processing stability and the residual stability of PE containing it is exceptional. Because of its large efficiency, 400–500 ppm additive is sufficient to achieve adequate stability for practice. Resveratrol interacts with the secondary phosphorous stabilizer used in the study, and the effect is antagonistic; resveratrol performs better alone than in combination with PEPQ. Accordingly, this unusual effect must be taken into account during formulation and the construction of the actual additive package. Resveratrol is used in other industries, thus it is available in large quantities and relatively cheap. Besides its advantages, the natural antioxidant has some drawbacks, like its high melting temperature, limited solubility in polyethylene, and strong color of its reaction products. Nevertheless, resveratrol has great potential as a stabilizer in certain products.