Hydrolytically Stable Dual-Dynamic Polyurethane Networks from Furfural

Dynamic polymer networks (DPNs) fabricated from renewable resources are being actively sought, ideally with recyclability and degradability. Furfural is a high-production-volume chemical, and most furfural-based DPNs contain acetals or imines, which are reported to be unstable under hydrolytic conditions. Herein, a furfural-based diol (FAH) containing a dynamic S,S-acetal group was prepared as an efficient chain extender and cross-linker for fabricating dual-dynamic polyurethane networks (PUNs). The structure of oligomeric diols (PEG, PTHF) and the ratios of FAH and bismaleimide were efficient tools to tune the mechanical properties from elastomers to rigid plastics with strength over 55 MPa. The dual-dynamic PUNs were featured with excellent stability during thermal reprocessing and hydrolytic incubation in 1 M HCl or 1 M NaOH solutions for up to 10 days, while solvent-assisted degradation can be readily achieved by refluxing in DMF or DMSO. This study represents a viable strategy to achieve furfural-based recyclable polyurethanes with hydrolytic stability and solvent-assisted degradability.