Degradable Waterborne Polyurethane with Flame Retardancy and High Mechanical Strength via Synergy of Hydrogen Bonds

Waterborne polyurethane (WPU) withdegradability is critical tothe environment. Especially, degradable WPU with high mechanical strengthand flame retardancy features various important industrial applications,while the increased flame retardancy often leads to reduced mechanicalstrength. Herein, we report the simultaneous realization of degradability,flame retardancy, and high mechanical strength into one design. Thetensile strength of degradable WPU is up to 39 MPa and can be tunedby the ratio of soft segments. The strong synergistic hydrogen bondinteractions of different components confirmed by FTIR and XPS aswell as molecular dynamics simulation are responsible for the excellentmechanical strength. Moreover, WPU achieves the highest V0level of flame retardancy. The simultaneous realization of the stressof 35 MPa and a limiting oxygen index of 27.55% is obtained by changingthe flame retardant contents. Importantly, WPU possesses degradabilitywith a mass loss rate of 37% after natural burial in soil for 3 months.The dense WPU coatings can be adhered to different substrates andalso have good anticorrosion ability. This work provides a promisingstrategy for high-performance biodegradable materials and expandsthe industrial application of polyurethane.

Automated summary

This study presents a waterborne polyurethane (WPU) design with degradability, flame retardancy, and high mechanical strength. The excellent mechanical strength is achieved through strong synergistic hydrogen bond interactions among different components. Additionally, the WPU exhibits outstanding flame retardancy, degradability, and corrosion resistance. This work provides a promising strategy for high-performance biodegradable materials and expands the industrial application of polyurethane.