Silver Composites of Ultradisperse Polytetrafluoroethylene and Its Fractions in Supercritical Carbon Dioxide: Synthesis and Structural Study

Abstract: Ultradisperse polytetrafluoroethylene is separated into fractions soluble and insoluble in supercritical carbon dioxide. The initial polymer and its soluble and insoluble fractions are impregnated with silver(I) (1,5-cyclooctadiene)-1,1,1,5,5,5-hexafluoroacetylacetonate in supercritical carbon dioxide solution for 6.6 h under thermodynamic conditions at 65°С and 8 MPa followed by reduction of the metal in an atmosphere of hydrogen for 6 h at 65°С and 1.2 MPa. According to X-ray fluorescence analysis, the content of the metal attains 2.4 wt %. Ag-polymer composites are studied by X-ray fluorescence spectroscopy, transmission electron microscopy, small-angle X-ray scattering, and X-ray photoelectron spectroscopy. It is shown that silver in the form of nanoparticles with a size of 1.0–7.5 nm is localized largely in the soluble low molecular weight fraction.