Nanocomposites of aromatic poly(amide-imide) with nanotubular Mg–Fe hydrosilicate

Composite films based on aromatic polyamide imide with carboxyl-containing fragments in repeating units (PAI-Ac) containing hydrosilicate nanotubes (Mg,Fe)$_3$Si$_2$O$_5$(OH)$_4$ are structurally sensitive to the molecular weight of the polymer used. According to Mössbauer spectroscopy data, nanotubes introduced into a polymer matrix generally retain their original structure. When using a polymer with a relatively low molecular weight, composite films are formed that are not stable during the pervaporation of cyclohexane and ethanol. In the case of a high-molecular polymer, the resulting MMM-type membranes are stable during pervaporation. They are more permeable to polar liquids compared to the base polymer and MMMs containing Mg$_3$Si$_2$O$_5$(OH)$_4$ nanotubes. Analysis of the found differences in the properties of the studied nanocomposites with iron-containing nanotubes in the PAI-Ac matrix from similar nanocomposites with magnesium-containing nanotubes leads to the conclusion about the need to study MMMs with iron-containing nanoparticles of a different structure.