A Novel In Situ Route to Fabricate PMIA/Graphene Oxide Nanocomposites with Tailored Multifunctional Properties

Poly-(<i>m</i>-phenylene isophthalamide) (PMIA) is a high-performance polymer recognized for its outstanding thermal stability, mechanical strength, and chemical resistance, making it well-suited for advanced material applications. In this work, PMIA/graphene oxide (GO) nanocomposites were synthesized using an in situ interfacial polycondensation technique, with GO incorporated at varying loadings (1, 3, 5, and 7 wt %). GO was prepared via the modified Hummers method to ensure improved dispersibility and surface reactivity. Fourier transform infrared (FTIR) spectroscopy confirmed successful chemical interactions between GO and the PMIA matrix, while scanning electron microscopy (SEM) revealed a morphological transition from smooth to increasingly porous surfaces with higher GO contents. Thermal analysis showed enhanced thermal resistance, with the decomposition onset temperature increasing from 400 °C for neat PMIA to 457 °C at 5 wt % GO. Mechanical testing demonstrated that the 5 wt % GO composite exhibited the best tensile strength (32.5 MPa) and elongation at break (33.5%). Dielectric measurements indicated that all GO-filled composites had lower dielectric constants than pure PMIA, with the minimum value of 2.3 observed at 3 wt % GO due to optimized interfacial polarization at lower loadings. However, the 5 wt % GO composite provided the most comprehensive performance overall, as higher loading more effectively enhanced both thermal stability and mechanical reinforcement. These findings highlight the potential of PMIA/GO nanocomposites as promising candidates for advanced applications requiring superior thermal and mechanical performance along with low dielectric properties, including electronic insulation and membrane systems.