Dual-dynamic vitrimerization upcycles post-consumer polypropylene into a durable recyclable material

Polypropylene is one of the most widely produced plastics, but its mechanical properties decline during recycling because of irreversible polymer chain breakage, limiting reuse and slowing the development of a circular polyolefin economy. Here we present a dual-dynamic vitrimer approach that converts post-consumer recycled polypropylene into a high-performance and fully recyclable material through covalent adaptable networks. A scalable two-step reactive extrusion process, involving glycidyl methacrylate grafting followed by the addition of 2,2′-dithiodibenzoic acid, creates a network that combines transesterification with reversible disulfide exchange. Gel fraction and rheological measurements confirm the formation of a stable yet reprocessable structure. The vitrimer shows a 24% increase in yield strength, a 31% increase in Young’s modulus, a twofold increase in complex viscosity, and a 9 °C increase in crystallization temperature. These properties remain stable after five recycling cycles. Molecular simulations, fused granulate fabrication, and techno-economic analysis further demonstrate network stability, manufacturability, and industrial potential. This strategy offers a scalable route for upcycling polyolefin waste into durable and recyclable materials. A dual-dynamic vitrimer network enhances yield strength by 24%, increases Young’s modulus by 31%, doubles complex viscosity, and retains performance through five recycling cycles, according to a two-step reactive extrusion process for post-consumer recycled polypropylene.