The role of reactive extrusion in mechanical recycling of plastics in geographically isolated economies

The continued accumulation of post-consumer plastic waste underscores the limitations of current recycling technologies, particularly when applied to heterogeneous and contaminated waste. These challenges are amplified in geographically isolated economies such as New Zealand, where centralised recycling infrastructure is often impractical. This review examines recent developments in reactive extrusion (REX) as a versatile, intermediate strategy that bridges conventional mechanical and energy-intensive chemical recycling approaches. Four REX-enabled strategies are highlighted: (1) dry-chemical approaches, (2) dynamic networks and structure control, (3) universal compatibilisers for multi-component blends and (4) partial depolymerisation and reconstruction. Together, these approaches provide pathways to recycle immiscible and contaminated plastic waste into economically valuable materials without requiring complete separation. As a next step, achieving industrial viability necessitates transitioning from laboratory-scale to pilot-scale demonstrations with real-world feedstocks containing additives and multi-phase polymer mixtures. Such targeted approaches are significant for aligning with market realities and ensuring the retention of material resources locally.