Study on Properties and Mechanism of Carboxylated MWCNTs Synergistically Modified Shape Memory Epoxy Resin

To address the application bottlenecks of DMF‐modified shape memory epoxy resin (SMEP), including insufficient toughness and reduced mechanical strength, a synergistic modification strategy using carboxylated multi‐walled carbon nanotubes (MWCNTs) was proposed in this study, and a novel MWCNT‐reinforced SMEP composite system was fabricated. Characterizations including Fourier transform infrared spectroscopy (FT‐IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TG‐DTG), and dynamic mechanical analysis (DMA) were performed, combined with tensile, flexural, and impact tests as well as fracture morphology observations. The effects of MWCNT content on the microstructure, thermal stability, mechanical properties, and shape memory behaviors of the composites were systematically investigated. The results demonstrated that carboxylated MWCNTs formed strong interfacial interactions with the SMEP matrix, which effectively suppressed filler agglomeration and improved interfacial bonding. With an optimized MWCNT content of 0.25 wt%, the composite exhibited the best balance between interfacial anchoring and thermal conductivity enhancement. Compared with neat SMEP, the MWCNT/D‐SMEP composite showed significantly enhanced tensile strength, flexural strength, and impact resistance while maintaining excellent thermal stability. Meanwhile, the shape fixity ratio reached 100%, and the shape recovery rate was maximized. This study not only provides an effective strategy to overcome the performance trade‐off between toughness and strength in DMF‐modified shape memory epoxy resins, but also reveals the interfacial interaction mechanism between MWCNTs and the D‐SMEP matrix. The findings lay a reliable experimental and theoretical basis for the design, preparation, and engineering applications of high‐performance intelligent shape memory composite materials.