Hydrogen bonds prevent obtaining high molar mass PHUs

Abstract

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. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44958.

From the Synthesis of Biobased Cyclic Carbonate to Polyhydroxyurethanes: A Promising Route towards Renewable Non‐Isocyanate Polyurethanes

“…Formation of hydrogen bonds : Recently, Blain et al. showed, through differential scanning calorimetry (DSC) and NMR spectroscopy, that low molar masses were not only due to the occurrence of side reactions, such as urea formation, but mainly due to hydrogen bonding . DSC reveals the presence of a second enthalpy of reaction, in addition to the enthalpy of reaction of the CC/amine system.…”

“…[70] Formation of hydrogen bonds:R ecently,B lain et al showed, through differential scanning calorimetry (DSC) and NMR spectroscopy, that low molar masses weren ot only due to the occurrenceo fside reactions, such as urea formation, butm ainly due to hydrogen bonding. [17,71] DSC reveals the presence of a second enthalpy of reaction, in addition to the enthalpy of reaction of the CC/amine system.T his explains why full conversion of monomers cannot be reached, and thus, the low molar mass of PHUs. NMR spectroscopy and additional DSC analyses provide evidence that hydrogen bondingp lays ak ey role in PHU polymerization, andt he hydrogen-bonding network is mainly responsible for the second enthalpy of reaction.…”

Wood adhesive application of poly(hydroxyurethane)s synthesized with a dimethyl succinate-based amide backbone

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