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

Abstract

Waterborne polyurethane (WPU) with degradability is critical to the environment. Especially, degradable WPU with high mechanical strength and flame retardancy features various important industrial applications, while the increased flame retardancy often leads to reduced mechanical strength. Herein, we report the simultaneous realization of degradability, flame retardancy, and high mechanical strength into one design. The tensile strength of degradable WPU is up to 39 MPa and can be tuned by the ratio of soft segments. The strong synergistic hydrogen bond interactions of different components confirmed by FTIR and XPS as well as molecular dynamics simulation are responsible for the excellent mechanical strength. Moreover, WPU achieves the highest "V0" level of flame retardancy. The simultaneous realization of the stress of 35 MPa and a limiting oxygen index of 27.55% is obtained by changing the flame retardant contents. Importantly, WPU possesses degradability with a mass loss rate of 37% after natural burial in soil for 3 months. The dense WPU coatings can be adhered to different substrates and also have good anticorrosion ability. This work provides a promising strategy for high-performance biodegradable materials and expands the industrial application of polyurethane.

Strategy for Constructing Phosphorus-Based Flame-Retarded Polyurethane Elastomers for Advanced Performance in Long-Term

“…To fulfill the environmental protection requirement, Liu [ 69 ] has successfully fabricated a degradable waterborne polyurethane that not only possesses both flame retardancy and high tensile strength (up to 35 MPa) but also can be degraded after being buried in the soil. These polyurethanes were made from degradable soft segments—such as polycaprolactone diol, Exolit ® OP 550, and castor oil—that originated from bio-based sources.…”

“…Meanwhile, the phosphoric acid and poly-phosphoric acid, which was also produced by FRPE, promoted the dehydration and carbonization of the matrix and increased the residual char rate and ignition time. To fulfill the environmental protection requirement, Liu [69] has successfully fabricated a degradable waterborne polyurethane that not only possesses both flame retardancy and high tensile strength (up to 35 MPa) but also can be degraded after being buried in the soil. These polyurethanes were made from degradable soft segments-such as polycaprolactone diol, Exolit ® OP 550, and castor oil-that originated from bio-based sources.…”

Nonisocyanate Polyurethanes Originated from Biobased Isosorbide with Good Combined Properties

“…Polyurethane (PU) has a very wide range of mechanical properties, such as excellent elasticity, toughness, and abrasion resistance, because its chemical structure and composition can be easily changed . PU has become the sixth-largest synthetic material in the world andis widely used in the fields of transport, construction, petrochemical, light industry, textile, electromechanics, electronics, aerospace, healthcare, and agriculture. − Generally, PU is synthesized from the polyaddition reaction of polyols and isocyanates, which are highly toxic and harmful to the environment and human health. − Phosgene is a highly reactive and readily available reagent for the production of isocyanates. However, phosgene is highly toxic and corrosive. , In addition, most raw materials for the preparation of PU are petroleum-based and nonrenewable.…”