Shape memory, mechanical and thermomechanical property comparison in MWCNT and GnP modified Bi‐directional (plain) carbon fiber polymer composites

The study presents a comparative analysis of MWCNT and GnP modified epoxy/bi‐directional (Plain) carbon fiber three‐phase shape memory hybrid composites (epoxy/BDP‐CF 3P‐SMHCs) focusing on their mechanical, thermomechanical, and shape memory properties. Fabrication involves preparing nanostructure‐modified epoxy nanocomposites through ultrasonication followed by hand layup technique. The findings revealed that the modified epoxy/BDP‐CF 3P‐SMHCs achieved their optimal performance at a 0.6 wt% concentration of nanostructure, with the tensile strength and modulus increasing by 63.62% and 28.30% for 0.6 wt% MWCNT composite and by 85.44% and 30.62% for 0.6 wt% GnP composite. In addition to the enhancement in tensile properties, improvements were also observed in flexural, ILSS, and thermal properties. These improvements can be attributed to the enhanced interfacial bonding between the polymer and fiber, as confirmed by morphological analysis of fractured tensile samples using FESEM. GnP‐modified epoxy/BDP‐CF 3P‐SMHCs outperformed MWCNT ones due to GnP's sheet structure aligning parallel to the load and larger surface area facilitating enhanced interaction with the matrix. Despite polymer modification, the shape recovery ratio values remained high, with 98.99% for unmodified composite, 97.95% for 0.6 wt% MWCNT modified epoxy/BDP‐CF 3P‐SMHCs, and 97.54% for 0.6 wt% GnP modified epoxy/BDP‐CF 3P‐SMHCs, all exceeding 90%, indicating no compromise in performance.Highlights 0.6 wt% optimal nanoparticle concentration boosts composite properties. GnP‐modified composites show superior properties increases over MWCNT. Tensile, flexural, thermal gains and ILSS link to better bond, FESEM proves. Recovery ratios over 90% in hybrid composites ensure peak performance.