Peculiarities of Polyimide Nanocomposites Structuring Depending on the Structure of the Inorganic Component

The influence of the content and structure of the inorganic component on the short-range order, degree of crystallinity, and permeability of the organic matrix of organo-inorganic (hybrid) nanocomposites based on linear polyimide and various ethoxysilanes, such as tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES), was considered using the methods of WAXS and radio spectroscopy at different component ratios. The nanocomposites based on linear polyimide (obtained by the interaction of pyromellitic dianhydride and 4,4'-diaminodiphenyl ether) and an inorganic component obtained using TEOS, TEOS:MTES at a ratio of 1:1, and TEOS:MTES at a ratio of 1:2 were investigated. TEOS forms an inorganic network with the general formula (SiO2)n, MTES forms a looser inorganic network with the general formula (CH3SiO1,5)n. The ethoxysilane content was 5 wt.%, 20 wt.%, or 50 wt.%. The data for the composites were compared with the characteristics of the original polyimide. The data showed that the amorphousness of the polyimide matrix increased with an increased proportion of MTES. The data showed that the amorphousness of the polyimide matrix increased with an increased proportion of MTES. A correlation was found between the permeability of nanocomposites and a structural parameter that characterizes the relationship between crystallite size and the period of short-range ordering of the polymer.