Electrostatic Compatibilization of Amorphous and Semicrystalline Immiscible Polymer Blends

The rapid accumulation of plastic waste underscores the urgent need for effective recycling strategies, yet conventional approaches are hindered by the immiscibility of chemically dissimilar polymers, which phase-separate upon blending and yield poor material properties. This study demonstrates a versatile strategy for electrostatic compatibilization, utilizing acid-base proton transfer between minimally functionalized polymers. Waste-derived polystyrene (PS) was successfully modified with <4 mol % acid groups, while amorphous polybutadiene (PBD) was functionalized with <6 mol % diethylamino base groups and subsequently hydrogenated to yield semicrystalline polyethylene (PE) with the same functionalization level as the PBD. In both cases, blending with functionalized PS produced optically transparent, mechanically robust films. Notably, increasing charge density from 1.0 to 3.5 mol % significantly reduced domain sizes, indicating enhanced compatibilization, while increasing PS molecular weight from 28 to 470 kDa led to a three-order-of-magnitude increase in toughness. In PE/PS blends, the preservation of crystallinity during melt reprocessing was achieved by maintaining low functionalization levels, demonstrating compatibility without sacrificing critical material properties. These findings establish electrostatic compatibilization as a powerful, scalable platform for creating high-performance materials from chemically diverse and mixed plastic waste streams.