Development and Characterization of Carbon Fiber Mat‐Reinforced Shape Memory Nanocomposites for Smart Structural Applications

ABSTRACT Shape memory polyurethane (SMPU) exhibits excellent shape memory behavior; however, its relatively low mechanical strength and thermal stability limit its use in demanding structural applications. In this study, carbon fiber (CF) mat‐reinforced SMPU composites containing multi‐walled carbon nanotubes (MWCNTs) were fabricated using a solvent casting technique to investigate the combined effects of CF mat reinforcement, MWCNT incorporation, and post‐fabrication annealing on the thermal, mechanical, morphological, and shape memory properties of SMPU composites. A controlled annealing treatment was performed below and above the glass transition temperature ( T g ), and 75°C for 2 h was identified as the optimum condition for enhancing composite performance. Differential scanning calorimetry (DSC) showed up to a 13% increase in the T g of the composite, whereas dynamic mechanical analysis (DMA) indicated improved storage modulus and thermomechanical stability after CF and MWCNT incorporation. The tensile strength of the S/CF/CNT‐1.0 composite increased by 134% compared with the as‐fabricated composite after optimum annealing. Furthermore, the developed hybrid composites exhibited enhanced shape‐fixity and rapid shape‐recovery behavior. The combined incorporation of CF and MWCNTs enhanced the thermal, mechanical, and shape memory performance of SMPU composites, making them promising for smart structural applications.