Compatibilization of LDPE/PP Waste Blends Using Acrylamide-Functionalized Phenol- Formaldehyde

This research focuses on improving the processability of mixed polyolefin waste by reactive extrusion of waste-derived low-density polyethylene (LDPE) and polypropylene (PP) with an acrylamide-functionalized phenol-formaldehyde (AF-PF) compatibilizer. The compatibilizer was specifically synthesized to enhance interfacial adhesion and promote uniform phase dispersion within the immiscible blend. Thermal analysis confirmed that AF-PF remained stable at the processing temperature of 190°C, maintaining its structural integrity during melt blending. The incorporation of AF-PF led to a transition from distinct, phase-separated melting peaks to a more unified thermal response, indicating enhanced phase interaction. SEM imaging revealed that the blend morphology shifted from coarse, heterogeneous domains to a finer and more continuous microstructure. Rheological characterization showed a marked decrease in melt flow rate, reflecting increased viscosity and improved cohesive strength within the matrix. Additionally, higher density values observed in the modified samples suggested the formation of a more compact and integrated structure. Collectively, these findings confirm the effectiveness of AF-PF in compatibilizing LDPE/PP blends, enabling the transformation of mixed polyolefin waste into structurally robust thermoplastic materials. This approach offers a promising pathway for advancing the upcycling of unsorted plastic waste into higher-performance applications.