Masoud RAMEZANZADEH1, Udo KRAGL1,2
1University of Rostock, Institute of Chemistry, Albert-Einstein-Str. 3a, 18059, Rostock, Germany
2University of Rostock, Department Life, Light & Matter, Albert-Einstein-Str. 25, 18059, Rostock, Germany
Introduction
Due to rising global carbon dioxide emissions and ongoing climate change, various approaches to capture and reduce CO2 have been widely studied over the past few decades. Conversion of CO2 as a low-cost, abundant, and non-toxic resource into valuable chemicals is one of the finest strategies to overcome this concern. Cyclic carbonates are one popular group of chemicals that can be prepared from the reaction of CO2 and epoxides. Moreover, cyclic carbonate derived from epoxidized vegetable oils can be used as an alternative feedstock to petrochemicals. Non-isocyanate polyurethane (NIPU) which mainly relies on the reaction of cyclic carbonate with amine is one of their outstanding applications (Javni, I., et. al., J. APPL. POLYM. SCI., 2013, 128: 566-571).
On the other hand, numerous amine components have been reported to be used in the synthesis of NIPU. However, amino-terminated imidazolium-based poly(ionic liquid)s (PILs) have been recently prepared successfully via multicomponent Radziszewski reaction. This reaction provides a simple one-step procedure to obtain the molecular designable main-chain PILs, including the chemical structure of the ionic liquid moiety and the molecular weight of the PILs. That means, diverse variations of the starting materials (e.g., diamine) can readily generate various PILs. Furthermore, the concentration and molar ratio of the starting materials, as well as the time and temperature of the polymerization reaction, can easily tune the mass of the obtained PILs (Lindner, J.-P., Macromolecules, 2016, 49: 2046-2053).
Synthesis
Herein, we present the synthesis of bio-based NIPU through the reaction of cyclic carbonated soybean oil and imidazolium-containing polymeric ionic liquids derived via the Debus-Radziszewski reaction. The cycloaddition reaction was tracked and approved by ATR-FTIR and NMR spectroscopy. 1,4-diaminobutane and 1,6-diaminohexane with 4 different molar ratios (n diamine/n carbonyl components) have been synthesized and their molecular weight measured by GPC. The main purpose of this study is to develop an eco-friendly method for the utilization of CO2 and soybean oil in order to prepare a NIPU network applicable to biomedical objectives like wound dressing. To the best of our knowledge, the incorporation of this novel polymeric ionic liquid into cyclic carbonated soybean oil to obtain a non-isocyanate polyurethane network has not been reported in the literature, and it is novel.