Oxime-Urethane Structure-Based Dynamically Crosslinked Polyurethane with Robust Reprocessing Properties

Crosslinked polyurethane with excellent mechanical property, solvent resistance, and transparency has become one of the most widely used materials. However, the presence of chemical crosslinks makes it difficult to be reprocessed once molded, which largely restricts its recycling and reusing, resulting in the serious waste problems. Therefore, it is of great significance to prepare a new type of crosslinked polyurethane with reprocessing function. In this work, a novel reprocessable polyurethane (DOPU) based on reversible dibutanone oxime-carbamate bonds is facilely prepared. The gel fraction of DOPUs is all higher than 95%, endowing it with excellent solvent resistance. Meanwhile, the visible light transmittance of DOPUs can reach up to 97.48%. After four thermal recycles, the tensile strength and elongation at break of recycled DOPUs can still remain at 3.21 MPa and 219.09%, respectively. Importantly, the synthesized DOPUs exhibit excellent elastic shape memory and permanent shape reconstruction properties under thermal stimulation. The dibutanone oxime-carbamate bonds can also be degraded under UV irradiation, making this material easily degradable. Hence, this material has potential applications in coatings, elastomers, and some other fields.

Automated summary

This article introduces a new type of crosslinked polyurethane (DOPU) with reprocessing function, which is prepared based on reversible dibutanone oxime-carbamate bonds. The DOPU exhibits excellent solvent resistance and transparency, and can maintain its mechanical properties even after multiple thermal cycles. Moreover, it demonstrates outstanding elastic shape memory and permanent shape reconstruction properties, and is easily degradable under UV irradiation.