Synergistic Effects of Reverse Kneading Blocks and Compatibilizers in a Twin‐Screw Extruder: Boosting Dispersion and Physical Properties of Recycled PP/PET

ABSTRACT Recycled polypropylene (PP)/polyethylene terephthalate (PET) blends often exhibit poor phase compatibility and suboptimal mechanical properties due to their inherent immiscibility. This study investigates the synergistic effects of reverse kneading blocks (RRK3) and chemical compatibilizers on filler dispersion, interfacial adhesion, and the tensile strength of extruded PP/PET blends. Using Ludovic simulation, the screw profiles were optimized to balance specific mechanical energy (SME: 493.2–637.9 kWh/t) and residence time distribution (RTD: 655.9–673.6 s). The blends, containing 5 wt% Cloisite 20A organoclay and 3 wt% PP‐g‐MAH, were characterized through SEM, TEM, tensile testing, and rheological analysis. The results revealed that RRK3 blocks increased local shear rates by up to 35% (reaching 1714.15 s −1 ), effectively reducing r‐PET domain sizes from 16.45 ± 3.88 μm to a minimum of 1.54 ± 0.23 μm. Rheological analysis showed that the storage modulus (G′) of the RRK3‐processed hybrid nanocomposite exhibited a 120% increase compared to the RK4‐processed blend, reflecting superior filler exfoliation and a robust internal network. Consequently, the tensile strength nearly doubled, increasing from 2.73 ± 0.10 to 7.11 ± 0.37 N/mm 2 ( p < 0.05). This scalable screw design and compatibilization strategy provide a robust pathway for producing high‐performance materials from recycled plastic blends, making them highly suitable for demanding industrial applications.