Poly(hydroxy urethane)s based on renewable diglycerol dicarbonate

In this paper, we present a series of amorphous non-isocyanate poly(hydroxy urethane)s (PHU) synthesized from diglycerol dicarbonate in bulk conditions at mild temperatures, without using a catalyst. Diglycerol dicarbonate has been synthesized from diglycerol and dimethyl carbonate and was subsequently reacted with various diamines to form PHUs. These fully bio-based PHUs were amorphous and displayed a broad range of T-g values i.e. from -7 to 66 degrees C. 1D and 2D NMR techniques were used to determine the ratio between primary and secondary hydroxyl groups formed along the PHU backbone, which was found to be 31:69 for all compositions. The number-average molecular weights were calculated from NMR data and range from 4100 to 9400 g/mol. In FTIR spectra, residual cyclic carbonate groups were observed, which is in agreement with the loss of diamine as detected by NMR. TGA analysis indicated that the polymers are stable up to 200 degrees C. The polymers synthesized are expected to perform well in e.g. coating applications, given their molecular and thermal properties as well as the abundance of reactive hydroxyl functionalities present along the PHU backbone, which can be used for curing purposes and/or further functionalization. (C) 2015 Elsevier Ltd. All rights reserved.