Functionalization of polypropylene, polyamide and cellulose acetate materials with pyrethrum extract as a natural repellent in supercritical carbon dioxide

This study discusses the possibility of supercritical solvent impregnation of polypropylene and polyamide fabrics as well as cellulose acetate in the form of beads and films with pyrethrum extract in order to fabricate functionalized materials with repellent properties. Impregnation experiments were performed at temperature of 40 degrees C and pressures of 10 and 20 MPa in supercritical carbon dioxide. The time of impregnation was varied from 0.5 to 18 h. Loadings of pyrethrum extract into polypropylene fabrics and cellulose acetate films higher than 30% were attainable at 10 MPa. In the case of polyamide fabrics and cellulose acetate beads, the pressure of 20 MPa was needed for obtaining the loadings higher than 11%. Pyrethrum extract release study revealed different capabilities of the tested materials for the repellent release, implying a variety of their possible applications. The impregnated solids were characterized by SEM, DSC, FTIR, Mercury intrusion porosimetry analyses and HPLC analyses.