Polyimide-Based Nanocomposite Coatings for Large Deployable Reflector (LDR) antennas: Solvent Processing, Filler Dispersion and Functional Characterization

Advanced nanocomposite coatings are increasingly relevant for space systems, where materials must combine thermal and electrical stability, adhesion to inorganic substrates, radiation hardness and compatibility with industrial processing routes. In this work, P84 polyimide coatings processed through two different solvent routes are investigated as candidate protective solutions for components of Large Deployable Reflector (LDR) antennas, where lightweight materials are required to withstand demanding space-relevant conditions. A greener route based on dimethyl isosorbide (DMI) is compared with a reference route based on N-methyl-2-pyrrolidone (NMP). Few-layer graphene (FLG) and few-layer hexagonal boron nitride (FL h-BN) are introduced as functional nanofillers to enhance selected coating properties. FLG is investigated for its potential contribution to thermal transport, thermal stability and interfacial interactions within the polymer matrix, while FL h-BN is considered for its thermal stability, dielectric properties and ability to support thermal management without significantly increasing electrical conductivity. Their incorporation, individually and in hybrid formulations, is intended to enhance the coatings’ suitability for LDR antenna components and in general for space structures. The aim is to compare the influence of solvent processing and filler dispersion on the final properties of thin polymeric coatings. The materials are characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), water contact angle measurements (WCA), surface free energy evaluation (SFE) and pull-off adhesion tests. The expected industrial impact lies in the development of lightweight, processable and multifunctional protective coatings for deployable antenna structures and more in general for space structures, providing useful indications for solvent selection, process optimization and scale-up toward more sustainable coating technologies for aerospace applications.