Poly(ε-caprolactone) (PCL) is considered as an ideal alternative to traditional petroleum-based plastics owing to its biodegradability, excellent flexibility and good processability. However, its practical application is limited by its low tensile strength and melting temperature. In this work, the polylactide (PLA) of a low amount of 5% in mass is employed as a reinforcing agent for PCL. Through a gamma-ray irradiation processing with the assistance of a trifunctional monomer, triallyl isocyanurate (TAIC), the obtained PCL/PLA blend plates exhibit strongly improved tensile yielding strength, reaching up to 25 MPa at the irradiation dose of 100 kGy, which is 2.5 times that for neat PCL (10 MPa). The gel content analysis, rheological measurement, dynamic mechanical analysis, scanning electron microscopy, wide-angle X-ray diffraction and small-angle X-ray scattering are taken to explore the reinforcing mechanisms. It is found that the dispersed PLA minor phase domains as spherical particles embedded in the irradiation-crosslinked PCL matrix with the improved interfacial compatibility and restricted phase mobility are mainly responsible for the strong improvement in the mechanical properties for the irradiated PCL/PLA 95/5 blends. This work provides an effective approach for the preparation of PCL plate materials with a well-balanced combination of tensile strength and toughness, which provides a reference for the mechanical enhancement of other soft biodegradable polymer systems.

https://doi.org/10.1016/j.polymer.2026.130295