Electron-Beam Radiation Crosslinking as a Route for Upgrading Recycled Polyethylene for Circular Economy Applications

The growing demand for polymer recycling requires effective approaches to improve the performance of recycled materials and expand their practical applications. In this study, electron-beam irradiation was investigated as a method for modifying recycled polyethylene obtained from façade-fastening elements. Virgin PE-80 polyethylene was used as a reference material for comparison. Irradiation was carried out using an ILU-10 electron accelerator (5 MeV) at doses of 95-125 kGy. Structural, morphological, elemental, thermal, crosslinking, and mechanical characteristics were evaluated using FTIR spectroscopy, SEM/EDS analysis, differential scanning calorimetry (DSC), gel fraction determination, and tensile testing according to ISO 527. The results showed that irradiation promotes the formation of a crosslinked network structure in both materials, as confirmed by the increase in gel fraction with increasing dose. For recycled polyethylene, gel fraction values increased from 46.7 to 56.2%, indicating effective radiation-induced crosslinking despite the structural heterogeneity of the material. FTIR analysis revealed the formation of oxygen-containing functional groups associated with radiation-induced oxidation, which was more pronounced in recycled polyethylene due to the presence of pre-existing defects and degradation products. SEM observations revealed increased surface roughness and localized fibrillar features after irradiation, while DSC analysis indicated a decrease in the crystallinity of recycled polyethylene associated with radiation-induced crosslinking and restricted molecular chain rearrangement. Mechanical testing showed an increase in tensile strength and elastic modulus accompanied by a reduction in elongation at break. Among the investigated irradiation doses, 110 kGy provided the most favorable balance between crosslinking efficiency and preservation of structural integrity. These findings demonstrate that electron-beam irradiation is an effective strategy for upgrading recycled polyethylene by improving its mechanical performance while maintaining structural integrity, thereby expanding its potential for reuse in circular economy applications.