Supercritical Extraction of a Natural Pyrethrin-Rich Extract from Chrysanthemum Cinerariifolium Flowers to Be Impregnated into Polypropylene Films Intended for Agriculture Applications

The extensive use of synthetic pesticides and their addition to the field presents significant environmental problems that must be minimized. The use of natural insecticides and their addition using techniques that minimize their impact in the field are widely studied by the current scientific community. In this work an extraction method based on supercritical CO2 to obtain a pyrethrin-rich natural extract from different varieties of chrysanthemum flowers is analyzed. This extract would be used in a supercritical solvent impregnation (SSI) process to produce a commercial polypropylene (PP) film with insecticidal properties to be used in greenhouses. The extract selected for the impregnation process was that obtained from the Atlantis variety at 35 °C and 10 MPa pressure. The amount of insecticide impregnated into the polymer at 55 °C and under two different pressure levels (10 MPa and 40 MPa) have been determined. A batch impregnation method (BM) with 5 h constant impregnation time and low depressurization rates were used to favor the impregnation process. The results demonstrated that this procedure was suitable to produce pyrethrin-loaded PP films that could to be used in greenhouses as a protection against pests, while allowing a more rational and moderate use of other chemical pesticides.