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

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.