Non‐Isocyanate Polyurethanes Derived From Commodity Biobased Isoprene via a Sustainable Synthesis Route

ABSTRACT Compared with conventional polyurethanes, non‐isocyanate polyurethanes (NIPUs) prepared via the polyaddition of bis(cyclic carbonates) and diamines have attracted considerable attention due to their avoidance of highly toxic precursors such as isocyanates and phosgene. However, the limited availability of bis(cyclic carbonates) has hindered the further industrialization of NIPUs. Therefore, we proposed a strategy for preparing NIPU using commercial biobased isoprene as starting material. As a proof of concept, A three‐step synthetic route was developed to convert isoprene into a series of bis(cyclic carbonates) via epoxidation, CO 2 cycloaddition, and thiol–ene click reactions. Subsequently, the designed cyclic carbonate monomers were copolymerized with four different diamine monomers to synthesize NIPUs. The molecular weight ( M n = 6.0∼24.0 kDa) and thermal properties ( T g = 1.4∼34.8°C) of the resulting NIPU could be tailored through regulating the structure of monomers. Additionally, the produced NIPU was applied as adhesive showed an adhesion strength up to 1.87 MPa on stainless steel substrates. The proposed strategy not only broadens the monomer sources of NIPUs but also effectively increases their biocarbon content.