Hydrogen bonds prevent obtaining high molar mass PHUs

Poly(hydroxyurethane) s (PHUs) are desired to replace PolyUrethanes (PUs) which are synthesized using harmful isocyanates. Nevertheless, the synthesis of PHUs starting from cyclocarbonates and amines displays two major drawbacks: the low reactivity observed during the opening of (poly) cyclocarbonates by (poly) amines and the low molar masses of polymers obtained. Currently, intensive work is carried out in order to increase the efficiency of the aminolysis of cyclocarbonates reaction but very few is dedicated to explaining the limitations of molar masses of PHUs. This article aims at demonstrating that the low molar masses can be explained by the existence of side reactions and the incomplete conversion of monomers during the polymerization. These conclusions were obtained after complete DSC and NMR studies that evidence that the incomplete conversion of monomers and therefore the low molar masses are caused mainly by hydrogen bonding and partly by the formation of urea. (C) 2017 Wiley Periodicals, Inc.