Self-healing Glass Fiber-Reinforced Epoxy Thermoset with High Strength, Tear and Impact Resistance

Epoxy fiber-reinforced polymers (FRPs) are extensively utilized in high-performance structural parts owing to their outstanding strength and rigidity. Nevertheless, their inherent brittleness and irreparability significantly shorten their service life, especially in demanding environments. Herein, a novel class of epoxy FRPs featuring high strength, enhanced toughness, and self-healing was presented via a dual-network curing design incorporating both rigid and flexible curing agents. Precise tuning of the network structural parameter R yielded well-balanced mechanical attributes, including tensile strength surpassing 400 MPa, tearing energy up to 430 kJ/m2, and healing efficiencies exceeding 90% across multiple damage-healing cycles. Dynamic boronic ester linkages embedded in the matrix enabled molecular rearrangements at elevated temperatures while preserving the thermoset framework. Mechanical evaluations and fracture morphology analyses indicated that an optimal R window (115-250) synergistically enhanced energy dissipation, interfacial bonding, and fiber-matrix stress transfer. This work establishes a design paradigm that harmonizes strength, toughness, and reparability, facilitating the development of durable and maintainable thermosetting composites for advanced structural applications.