Special interplay of hydrogen bonds and dynamic covalent bonds in sustainable polyurethane vitrimers with excellent recyclability and reprocessability

Abstract

Constructing various reversible bond networks is one of the effective methods to endow polymers with high mechanical properties and recyclability. However, the interplay mechanisms between different reversible bond networks have not been fully understood. In the current work, polyurethane (PU) vitrimers containing covalent crosslinking networks, dynamic imine bond networks and hydrogen bond networks were prepared. The PU vitrimers exhibit high mechanical properties (tensile strength and modulus), excellent recyclability and reprocessability. The incorporation of the dynamic imine bonds leads to an increase of the number of hydrogen bonds in the PU vitrimers, and improves the degree of microphase separation between soft and hard segments. The presence of this unique interplay between the two different reversible bond networks endows the PU with superior comprehensive properties. These above findings are helpful in guiding the design and development of sustainable PU materials with high comprehensive properties.