Structure and Properties of Nanocomposites Based on Polyimides with Different Chemical Structures and Metalloalkoxysiloxanes

The morphology and physical properties of nanocomposites based on organosoluble polyimides with different chemical structures are studied. Metalloalkoxysiloxanes that differ in terms of the type of the central metal atom and substituent at the silicon atom, namely, tris(3-aminopropyldiethoxysiloxy)chromium, tris(methyldiethoxysiloxy)gallium, and tetrakis(methyldiethoxysiloxy)titanium, are used as precursors of the dispersed phase. It is shown that the difference in the chemical structure of the matrix polymer, provided that the same precursor of the dispersed phase of the nanocomposite is used, manifests itself in a change in the shape and sizes of the nanoparticles formed in the polymer. Filled polyimide films are characterized by a high resistance to atomic oxygen. The values of the erosion coefficients of the nanocomposites based on them when using tetrakis(methyldiethoxysiloxy)titanium are 89% lower when compared to unfilled polyimides. The ability of the filled polymer films to withstand the erosive action of an incoming oxygen plasma is to a greater extent determined by nanoparticles of the dispersed phase. The protective function of nanoparticles increases with an increase in the number of Si–O–Si blocks in their structure which, in turn, is predetermined by the valence of the central metal atom of the precursor. Thus, polyimides with particles based on tetrakis(methyldiethoxysiloxy)titanium are less susceptible to erosion under the action of atomic oxygen when compared to nanocomposites, the dispersed phase of which is formed based on tris(3-aminopropyldiethoxysiloxy)chromium and tris(methyldiethoxysiloxy)gallium. The chemical structure of the matrix polymer has little effect on the values of the erosion coefficients of the filled polyimide films.