Metal coordination network polyurethane adhesives based on energy dissipation mechanism: Excellent adhesion and flame retardant properties

Polyurethane adhesives with excellent adhesion and excellent flame retardant properties are particularly important in the development of today's construction and wood industries. In this paper, a kind of bio-based polyurethane adhesive with strong adhesion and excellent flame retardant properties was reported by designing an "umbilical cord" type metal coordination network structure. Metal coordination bonds act as an "umbilical cord" between cohesion and bonding strength. It connects the cohesion and bonding strength, dissipates the energy in time to cope with the external stress applied, and improves the adhesion strength. This approach addresses the issue of adhesion failure under external stress and makes the adhesive demonstrates excellent adhesion performance. The lap shear adhesion strength on the wood shows an impressive 7.5 MPa (work of debonding of 20146 N & sdot;m-1). At the same time, due to the special design of the "umbilical cord" type and the introduction of the inverse vulcanized mechanism, the problem of agglomeration of inorganic fillers in the polymer network is solved while achieving high bonding strength, and the efficient flame retardant effect of polyurethane adhesive is realized. The highest V-0 flame retardant rating can be achieved in the UL-94 test. The raw materials for this work can come from industrial or agricultural by-products. Breaking with the traditional preparation method of polyurethane adhesives, directly synthesized by a solvent-free one-pot process, this provides a "sustainable" strategy, thus providing a new way of thinking about the use of industrial and agricultural waste.