Wuxi, China – Scientists at Jiangnan University have found a way to upcycle thermoplastic polyurethane. They used a chain breaking-crosslinking strategy to create covalent adaptable networks (CANs) from the TPU.
This was achieved by extruding the TPU with polyol and IPDI on a micro twin-screw extruder. The carbamate exchange between the polyol and the TPU breaks the TPU chains, introducing reactive hydroxyl groups and activating the TPU. These long chain branched TPUs with additional hydroxyl groups can then be cross-linked with IPDI, resulting in highly cross-linked networks.
The scientists claim the PU-CANs show improved mechanical properties and elastic recovery rate. The cross-linked network also enhances the material’s creep resistance and solvent resistance. The CANs, they said, maintain favourable reprocessability, and are suitable for both screw extrusion and hot press processing.
The work has been published in the Journal of Polymer Science.
