Compatibilizer-aided Fabrication of a ‘High-entropy Polymer Blend’

High-entropy polymer blends composed of polypropylene (PP), polystyrene (PS), polyamide 6 (PA6), poly(lactic acid) (PLA), and styrene-ethylene-butylene-styrene (SEBS) were successfully fabricated using maleic anhydride-grafted SEBS (SEBS-g-MAH) as a compatibilizer. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and mechanical testing demonstrated that SEBS-g-MAH significantly enhanced the compatibility between the polar (PA6, PLA) and nonpolar (PP, PS, SEBS) components. The compatibilizer effectively refined the microstructure, substantially reduced the domain sizes, and blurred the phase boundaries, indicating enhanced interfacial interactions among all the components. The optimal compatibilizer content (15 wt%) notably increased tensile ductility (elongation at break from 5.0% to 23.7%) while maintaining balanced crystallization behavior, despite slightly decreasing modulus. This work not only demonstrates the broad applicability of high-entropy polymer blends as a sustainable strategy for converting complex, unsorted plastic waste into high-performance value-added materials that significantly contribute to plastic upcycling efforts, but also highlights intriguing physical phenomena emerging from such complex polymer systems.