Diamine derivatives of dimerized fatty acids and bio-based polyether polyol as sustainable platforms for the synthesis of non-isocyanate polyurethanes

Abstract

A series of environmentally friendly non-isocyanate polyurethanes (NIPUs) were successfully prepared via the polyaddition reaction of bio-based polyether polyol-based cyclic carbonate with diamine derivative of dimerized fatty acids. The syntheses of NIPUs were realized by the three-step method in the absence of toxic solvents and, importantly, the process of carbonation did not require the use of elevated pressure. The effect of using various types of bio-based amines, [amine]/[cyclic carbonate] molar ratio as well as different reaction temperatures on the chemical structure and thermal properties were widely investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), respectively. The Gaussian deconvolution technique was used to decompose the carbonyl region (-CO) of three peaks in various samples. It was found that the molar ratio of substrates and curing temperature have an effect on the distribution of free and H-bonded carbonyl groups as well as carbonyl groups from cyclic carbonates in the chemical structure of the prepared compounds. On this basis, the role of hydrogen bonds in the chemical structure of NIPU on selected sample properties was determined. Moreover, the impact of water during 6 months of immersion on the polymer networks was examined.