Strong Interfacial Adhesion Enables High‐Performance Transparent PMMA Composites Reinforced With Electrospun PETG Nanofibers

ABSTRACT Poly(methyl methacrylate) (PMMA) is a commonly used polymer in biomedical, optical, and structural fields, but it has inherent limitations such as low tensile strength, poor toughness, and insufficient interfacial compatibility with reinforcing phases, which restrict its application in load‐bearing scenarios. To address these issues, we fabricated transparent composite films via an all‐nanofiber layer‐by‐layer hot‐pressing consolidation approach, employing electrospun PETG nanofibers blended with PMMA nanofiber mats as the reinforcement and PET nanofiber‐reinforced PMMA composites as the control. The two types of nanofibers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, mechanical tests, and finite element simulation, and the effects of nanofibers on the light transmittance and mechanical properties of the composites were systematically investigated. Remarkably, compared with both the PET nanofiber‐reinforced PMMA composite and neat PMMA, the introduction of PETG nanofibers led to substantial improvements in mechanical performance: tensile strength increased by 19% and 26%, while fracture toughness was enhanced by 80% and 260%, respectively. Such enhancements are attributed to the efficient stress transfer between the PETG nanofibers and the PMMA matrix, which effectively suppresses crack propagation and retards interfacial debonding. Overall, the PETG/PMMA composite films retain the high optical transparency of PMMA while delivering significantly superior mechanical properties over the PET/PMMA system. This work thus offers a feasible and effective pathway to mitigate the intrinsic deficiencies of PMMA and expand its practical applicability in advanced transparent structural materials.