Non-Isocyanate Polyurethanes (NIPUs) Incorporating Isomers of Abundant Sugar-Derived 1,4:3,6-Dianhydrohexitols

Non-isocyanate polyurethanes (NIPUs) are attracting significant attention as alternatives to traditional polyurethanes (PUs). This interest stems from the replacement of toxic diisocyanates which are combined with diols in their synthesis. These toxic compounds are replaced with bis-cyclic carbonates, which are reacted with diamines, whereby these cyclic carbonates can be obtained from the atom-efficient cycloaddition of epoxides with carbon dioxide (CO2). Still further, at present the preparation of bis-cyclic carbonates incorporating bioderived compounds into their structure is beginning to bring a further increased sustainability profile to these monomers. This work describes the preparation of bis-cyclic carbonates derived from 1,4:3,6-dianhydrohexitols (isosorbide, isomannide, and isoidide) and their application as monomers in the synthesis of NIPUs. The effect of the stereochemistry of the bis-cyclic carbonate monomer and the variation of the structure of the diamine on the properties of the final polymers are presented and discussed. Finally, given the presence of stereochemistry in the bis-cyclic carbonate monomers, examples of the optical properties of the NIPUs obtained are provided.