Reprocessable Cross-Linked Polyurethane with Dynamic and Tunable Phenol–Carbamate Network

Polyurethanes with covalent adaptable networks (CANs) have received extensive attention due to their recyclability and self-healability; meanwhile, how to design and regulate the structure and properties of dynamically cross-linked polyurethanes with biobased monomers is of particular interest. Herein, we design a new type of dynamically cross-linked polyurethane derived from biobased polyol (castor oil) and industrial bulk products: bisphenol and isophorone diisocyanate. Furthermore, we develop a strategy to regulate the rearrangement kinetics of the dynamic covalent networks. The stronger the electron-withdrawing effect of the structure between the two benzene rings in bisphenol, the easier the network rearrangement and the lower the initial temperature of dynamic bonds dissociation. By varying the type and ratio of mixed bisphenols, the initial temperature of dynamic bond disassociation and the rate of network rearrangement can be adjusted within a wide range. In addition, by changing the cross-linking degree, the mechanical properties, glass-transition temperature, and network rearrangement rate can also be tuned. In this work, we have established a new method for designing biobased polyurethanes with CANs, which is beneficial for developing self-healing and recyclable cross-linked polyurethanes with variable properties from biobased feedstock and industrial bulk products.