###### Abstract  
To improve the reliability of glass-fiber/epoxy-reinforced polymer (GFRP) composites, four laminates were manufactured by vacuum bagging: (i) a virgin baseline, (ii) an epoxy system modified with 15 wt% high-density polyethylene (PE) powder, (iii) a laminate interleaved with electrospun polyacrylonitrile (PAN)-based nanofiber mats, and (iv) a hybrid combining both modifiers. The specimens were subjected to low-velocity impacts; half were then heated at 150 \({}^{\circ}\)C for 30 min and re-impacted. PE caused peak-load loss up to 30% compared to virgin specimens but recovered 25% after heating by filling cracks. PAN interleaves limited the loss to 5%, and the hybrid laminate merged the benefits: it showed the highest first-impact load, retained 96% on re-impact, and gained a further 10% after heating while keeping the smallest permanent indentation. SEM confirmed molten PE migrating along the nanofiber mat to repair delamination fronts, explaining the laminate's bell-shaped, oscillation-free force response and demonstrating a practical, synergistic self-healing mechanism. Collectively, the results demonstrate a clear structure-property connection: PAN nanofibers capture crack growth, while PE provides temperature-triggered self-healing, and their synergy offers a practical pathway to lightweight GFRP structures with enhanced impact resilience and restoration of mechanical integrity. G 2025 15, 8795 2025 20  
capacity while accelerating long-term degradation [2]. Consequently, GFRP composites often exhibit limited impact tolerance; even relatively low-energy impacts can introduce internal damage that may not be immediately visible but can propagate under cyclic or sustained loading conditions. This hidden damage may ultimately lead to catastrophic failure, thereby reducing the operational lifespan of the component or rendering it entirely unserviceable. Indeed, several studies have shown that low-velocity impacts can initiate internal fracture mechanisms in composite materials, including matrix cracking and fiber-matrix debonding [3,4]. These damage modes frequently remain undetectable in early stages yet continue to grow over time, compromising the reliability and long-term performance of GFRP structures. Consequently, enhancing damage tolerance and integrating smart functionalities into composite materials represent major areas of ongoing research in advanced composite technology, among which self-healing has emerged as a particularly promising approach [5]. Self-healing methods in polymeric systems are generally categorized as either intrinsic or extrinsic [6], each employing different strategies to trigger the self-healing mechanism. Intrinsic self-healing approaches typically rely on reversible covalent bonding or reversible intermolecular interactions [7], among other methods. In contrast, extrinsic methods utilize embedded microcapsules, thermoplastic particles, vascular networks, or hollow fibers as healing reservoirs [8]. Upon damage, these healing agents are released into the crack zone through external stimuli, leading to autonomous repair of the material. Interrupted fatigue tests on fiber-reinforced epoxy composites containing thermoplastics have demonstrated that early-stage damage recovery can significantly extend fatigue life [9, 10, 11, 12, 13]. For example, [PERSON] et al. [14] conducted a study to evaluate the effect of self-healing agent content on the mechanical behavior of composite laminates. Their ANOVA analysis revealed that the fraction of healing agent had a more significant impact on the mechanical properties than the internal dispersion within the same laminate prior to the healing cycle. The results indicated a linear reduction in shear stress with increasing poly(ethylene-co-methacrylic acid) content, which was attributed to the decreased stiffness caused by the ductile nature of the thermoplastic.