Sustainable Enhanced Regeneration and Properties Analysis of Waste LLDPE Films through Micro-Cross-Linking Modification

The recycling and reuse of waste plastics is an indispensable approach to achieving a low-carbon economy and sustainable social development. To realize the high-value recycling and carbon emission reduction of waste linear low-density polyethylene (LLDPE) films, this study used dicumyl peroxide (DCP) for micro-cross-linking modification of LLDPE and systematically investigated the effect of DCP dosage on the structure and properties. The results showed that the physical properties of recycled LLDPE could be effectively regulated by DCP. When the DCP addition amount was 0.05–0.1 wt %, the melt flow index of the material decreased to 1.485 and 0.795 g/10 min, respectively, which matched the blow molding and extrusion processes. Moreover, the impact strength and tensile strength were significantly improved compared to the unmodified samples. Meanwhile, characterizations by FTIR and DSC confirmed that the structure and thermal behavior were stable and controllable. With the increase of DCP dosage to 0.3 wt %, the impact strength, tensile strength, and flexural strength of recycled LLDPE were further enhanced. Rheological tests showed that the cross-linking network could improve the melt strength, meeting the requirements of different molding processes. Carbon footprint assessment indicated that based on the recycling process in this study, the carbon emission equivalent of recycled cross-linked LLDPE was 0.397 kg CO 2 e/kg, which was 84.73% lower than that of virgin LLDPE (2.60 kg CO 2 e/kg), conforming to the principles of circular economy. Through DCP micro-cross-linking modification, this study expands the ways and application scenarios for the reuse of waste LLDPE films, provides a technical path with controllable properties, and simultaneously offers practical support for carbon emission reduction in the plastic recycling industry.