The development of advanced materials for space environments requires an optimal combination of thermal stability, electrical conductivity, low density, and radiation resistance. In particular, these materials need to maintain their structural and functional integrity during long missions in harsh and often unpredictable space conditions. In this context, polyimides (PIs) represent a promising class of polymers, due to their excellent stability in space environments. The incorporation of specific fillers, such as graphene, significantly enhances the performance of PIs, improving their resistance as well as increasing their hydrophobicity and electrical conductivity.
In this work, nanocomposite membranes based on aromatic and fluorinated polyimide with 5-20 wt% of graphene nanoplatelets (GNPs) were synthesized and characterized. An eco-friendly chemical approach was employed using a green and bio-based solvent, dimethyl isosorbide (DMI), for the synthesis of both pristine PI and PI/GNP nanocomposites.
Several experimental techniques were used to investigate the physical, chemical, thermal, electrical, and morphological properties of membranes, assessing their potential applications in space environments. Optical microscopy and SEM analysis confirmed good dispersion of GNP within the PI matrix and increasing roughness with GNP content. FTIR and DSC analyses indicated successful imidization of PI and high glass transition temperature (~200 °C) for all samples. An increase in GNP loading resulted in enhanced hydrophobicity, as demonstrated by water contact angle and surface free energy measurements. Electrical analysis indicated a shift from insulating behavior in pristine PI to conductive behavior in the PI/GNP nanocomposites. Indeed, a higher concentration of GNPs resulted in lower impedance values and improved electrical conductivity.
Overall, the multifunctional properties of these materials highlight their strong potential for use in aerospace applications, including antibacterial coatings, flexible electronics, and sensor systems in long-duration space missions.
