Molecular Weaving of Polyamide-6 Chains with a Covalent Organic Framework for Enhanced Mechanical Performance

Abstract Polyamide-6 (PA6) fibers are widely used owing to their excellent mechanical properties, outstanding processability, and superior resistance to abrasion and wear. However, PA6 fibers with high tensile strength remains in urgent demand to meet the requirements of emerging application environments. Herein, we present a strategy of reinforcing PA6 fibers by incorporating a small amount (0.5 wt %) of a covalent organic framework (COF) during melting spinning. Because of the formation of a molecular weaving structure between PA6 chains and COF sheets, the PA6 fiber exhibited a high tensile strength of 771.2 ± 46.2 MPa, which was significantly higher than that of the neat PA6 fiber (618.1 ± 50.1 MPa) fabricated under identical processing conditions. In addition, the thermal stability of the composite fiber was enhanced after the addition of the COF. Further experimental results provided valuable insights into how the COF and hot-drawing synergistically promoted the structural evolution and mechanical enhancement of PA6 fibers. Our work demonstrates that weaving PA6 chains with COFs is an effective strategy for augmenting the mechanical performance of PA6 fibers.