Synergistic electronic-topological strategy enables spatiotemporal control of covalent adaptable networks

Covalent adaptable networks (CANs) hold considerable promise for combining the advantages of thermosets and thermoplastics. However, their use in high-speed melt spinning is restricted by insufficient dynamic bond reactivity at processing temperatures and the mismatch between network rearrangement kinetics and industrial requirements. Here, we establish a spatiotemporally regulated platform based on internally catalyzed oxime-urethane chemistry within a four-arm cross-linking topology. Neighboring urea groups provide internal catalysis that greatly accelerates oxime-urethane dissociation at 110°C, improving melt fluidity. During extrusion, the slight temperature drop rapidly drives bond recombination within the four-arm topology, while hydrogen bonds deliver immediate reinforcement to retain melt strength. This synergistic design enables continuous melt spinning at 100 meters per minute over a short 10-centimeter distance. The resulting fibers combine high mechanical performance (tensile strength: 261.7 megapascals; toughness: 630.1 megajoules per cubic meter) with excellent stretchability, self-healing, and recyclability. This molecular engineering approach overcomes the processing-performance tradeoff in CANs, offering a scalable pathway toward high-performance, sustainable polymers for industrial manufacturing.