Bio-derived polyurethanes obtained by non-isocyanate route using polyol-based bis(cyclic carbonate)s-studies on thermal decomposition behavior

Non-isocyanate polyurethanes (NIPUs) constitute one of the most prospective groups of eco-friendly materials based on their phosgene-free synthesis pathway. Moreover, one of the steps of their obtaining includes the use of carbon dioxide (CO2), which allows for the promotion of the development of carbon dioxide capture and storage technologies. In this work, non-isocyanate polyurethanes were obtained via three-step synthesis pathway with the use of epichlorohydrin. In the I step, the addition reaction of epichlorohydrin with polyhydric alcohols was conducted for diglicydyl ethers obtaining. In the II step carbon dioxide reacted with diglicydyl ethers to obtain five-membered bis (cyclic carbonate)s in the cycloaddition reaction. Then, one-pot polyaddition reaction between bis (cyclic carbonate) and dimerized fatty acids-based diamine allowed for non-isocyanate polyurethanes (NIPU)s preparation. Three bio-based materials (two semi-products and one bio-NIPU) and three petrochemical-based materials (two semi-products and one NIPU) were obtained. The selected properties of the products of each step of NIPUs preparation were compared. Fourier transform infrared spectroscopy FTIR and proton nuclear magnetic resonance H-1 NMR measurements allowed to verify the chemical structure of all obtained products. The average molecular masses of the semi-products were measured with the use of size exclusion chromatography SEC. Moreover, thermal stability and thermal degradation kinetics were determined based on thermogravimetric analysis TGA. The results confirmed that the activation energy of thermal decomposition was lower for semi-products and NIPUs prepared with the use of petrochemical-based epichlorohydrin than for their bio-based counterparts.

Automated summary

Non-isocyanate polyurethanes (NIPUs) are eco-friendly materials synthesized without the use of phosgene, and their production process involves the reaction with carbon dioxide. In this study, NIPUs were successfully obtained through a three-step synthesis pathway using epichlorohydrin. The properties and structures of the obtained materials were compared, and it was found that NIPUs prepared with petrochemical-based epichlorohydrin had lower thermal decomposition activation energy compared to their bio-based counterparts.