Comparative Effects of Gamma Irradiation and Electron Beams on Mechanical, Thermal, and Optical Properties of Polypropylene–Coumarin/Dicmyl Peroxide Composites Performance

ABSTRACT 2.5 wt% coumarin derivative and 2.5 wt% coumarin derivative/0.5 wt% dicumyl peroxide (DCP)‐based polypropylene (PP) composites were synthesized and exposed to electron beam (EB) and gamma rays at absorbed doses of 25 and 50 kGy to study the effect of irradiation mode and dose on the mechanical, thermal, structural, optical, and morphological characteristics. The novelty of this work lies in the combined use of a fluorescent radiation‐responsive coumarin derivative and DCP, together with a direct comparison of EB and gamma irradiation, to investigate how functional additives influence the radiation‐induced modification of PP. The composites were analyzed by tensile testing, thermogravimetric analysis (TGA), Fourier‐transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–Vis) spectroscopy, fluorescence microscopy, electron spin resonance (ESR), and scanning electron microscopy (SEM). The results revealed that the properties of PP composites were evidently changed by irradiation, and the best mechanical properties were gained at 25 kGy. EB irradiation led to a superior tensile strength when compared to gamma irradiation at the same dose, while gamma irradiation at 50 kGy induced the maximum enhancement in thermal stability. Radiation‐induced radicals ESR revealed changes in the amount of radiation‐induced radicals and FTIR, UV–Vis, fluorescence and SEM analyses showed radiation‐induced structural and optical changes. The observed changes are consistent with the combined influence of the coumarin derivative and DCP on the radiation response of PP through competing chain scission and radical recombination processes. This approach provides a promising route for developing multifunctional PP composites for advanced engineering applications, UV‐protective packaging, electrical insulation, and radiation‐responsive polymer systems.