Synergistic Dispersion and Interfacial Reinforcement of MWCNTs in PA6 Nanocomposites Enabled by PVP : Enhancing Mechanical Performance

ABSTRACT Achieving uniform dispersion and strong interfacial interaction of carbon nanotubes (CNTs) in polymer matrices remains a key challenge in the development of high‐performance nanocomposites. Herein, PA6 nanocomposites were prepared via in situ ring‐opening polymerization using multi‐walled CNTs (MWCNTs) and polyvinylpyrrolidone (PVP) as a dispersant. By adjusting MWCNT content (0.1–0.5 wt.%) and PVP/CNT ratio, we elucidated the role of PVP in improving dispersion and interfacial compatibility. PVP enabled non‐covalent interactions (π‐π stacking and hydrogen bonding), leading to reduced CNT agglomeration and enhanced load transfer. Notably, the nanocomposite containing 0.3 wt.% MWCNTs and 0.3 wt.% PVP demonstrated the most balanced mechanical enhancement, achieving increases of 21.9% in tensile strength, 17.2% in tensile modulus, 15.8% in flexural strength, and 32.2% in impact strength compared to PA6. These improvements highlight the synergistic role of PVP in promoting nanotube dispersion and interfacial load transfer. Moreover, rheological analysis revealed a viscosity‐enhancing effect induced by the semi‐interconnected CNT‐PVP structure, which hindered molecular mobility and contributed to stress transfer across the interface. This work elucidates the molecular‐level mechanism of PVP‐assisted CNT dispersion in PA6 nanocomposites and highlights a scalable strategy for tailoring interfacial structures in CNT‐reinforced thermoplastics, offering valuable insights into the rational design of high‐performance nanocomposite systems.