Nonisocyanate Polyurethanes Based on Cyclic Carbonates

Polyurethanes (PUs) are among the most demanded polymers, are required by modern technologies, and the worldwide consumption of PU has steadily increased. Of PU production 80% now consists of resilient and rigid foams while 20% remains solid PU (elastomers, coatings, adhesives, etc.) [1], 

Despite its steady consumption, conventional PU has inherent weaknesses based on its molecular composition. The physical and mechanical properties of PU are mainly dependent on van der Waals forces. However, the strength of these bonds is significantly lower in energy [1], Therefore, PU does not satisfactorily withstand loads, especially at elevated temperatures. 

NIPU networks are created by the reaction between polycyclic carbonate oligomers and aliphatic or cycloaliphatic polyamines with primary amino groups [4], This forms a cross-linked polymer with p-hydroxy urethane groups of a different structure—polyhydroxyurethane polymer. Since NIPU is obtained without using highly toxic isocyanates, the process of synthesis is relatively safe for both humans and the environment in comparison to the production of conventional polyurethanes. Moreover, NIPU is not sensitive to moisture in the surrounding environment. 

Hydroxyl groups formed at the p-carbon atom of the urethane moiety increase adhesion properties. Plurality of intra- and intermolecular hydrogen bonds 

STRUCTURE 4.1 Hydrogen bonding in a hydroxyurethane. (Reprinted from E. Delebecq, J-P. Pascault, B. Boutevin, and F. Ganachaud, On the Versatility of Urethane/Urea Bonds Reversibility, Blocked Isocyanate, and Non-Isocyanate Polyurethane, Chem. Rev. 113 (2013) 80-118. With permission.) 

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Source Reprinted from O. Figovsky, L. Shapovalov, A. Leykin, O. Birukova, and R. Potesshnikova, Nonisocyanate Polyurethanes Based on Cyclic Carbonates and Nanostructures Composites, J. Scientific Israel Technology Advanced 14, no. 4 (2012) 95—106. With permission. 

Leykin, A., Beilin, D., Birukova, O., Figovsky, O., and Shapovalov L. Nonisocyanate Polyurethanes Based on Cyclic Carbonate Chemistry and Application (review), Scientific Israel Technological Advantages 11, nos. 3—4 (2009) 160-190. 

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