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

Non-isocyanate polyurethanes (NIPUs) are attracting significant\nattention as alternatives to traditional polyurethanes (PUs). This\ninterest stems from the replacement of toxic di­isocyanates which\nare combined with diols in their synthesis. These toxic compounds\nare replaced with <i>bis</i>-cyclic carbonates, which are\nreacted with diamines, whereby these cyclic carbonates can be obtained\nfrom the atom-efficient cycloaddition of epoxides with carbon dioxide\n(CO<sub>2</sub>). Still further, at present the preparation of <i>bis</i>-cyclic carbonates incorporating bioderived compounds\ninto their structure is beginning to bring a further increased sustainability\nprofile to these monomers. This work describes the preparation of <i>bis</i>-cyclic carbonates derived from 1,4:3,6-dianhydrohexitols\n(isosorbide, isomannide, and isoidide) and their application as monomers\nin the synthesis of NIPUs. The effect of the stereochemistry of the <i>bis</i>-cyclic carbonate monomer and the variation of the structure\nof the diamine on the properties of the final polymers are presented\nand discussed. Finally, given the presence of stereochemistry in the <i>bis</i>-cyclic carbonate monomers, examples of the optical properties\nof the NIPUs obtained are provided.