In this work, three different cyclic carbonates are obtained from renewable diols and transformed into carbamates by reacting them with renewable 11-amino undecanoic acid methyl ester to synthesize non-isocyanate poly(ester urethane)s in a sustainable manner. A procedure using 2,3-butanediol (2,3-BDO) as a renewable starting material to synthesize a cyclic carbonate with dimethyl carbonate (DMC) is introduced, catalyzed by 1,5,7-triazabicylco[4.4.0]dec-5-ene (TBD). Three purification strategies, i.e., column chromatography, extraction, and distillation, are compared regarding their E-Factors. Propylene glycol (PG) and ethylene glycol (EG) are used as alternative starting materials to broaden the substrate scope and compare material properties, their cyclic carbonates likewise react to carbamates with 11-amino undecanoic acid methyl ester. All carbamates are then polymerized in a bulk polycondensation reaction, yielding non-isocyanate polyurethanes (NIPUs), specifically poly (ester urethane)s, with molecular weights (M n ) up to 10 kDa. Complete characterization is reported using differential scanning calorimetric (DSC), size exclusion chromatographic measurements (SEC), 1 H-NMR as well as IR spectroscopy. The rheological properties of the poly(ester urethane)s are investigated in the framework of small amplitude oscillatory shear (SAOS) and uniaxial elongation.
A CO2 switchable solvent system is investigated to find an environmentally friendlier way to produce man‐made cellulose fibers. Cellulose solutions with concentrations from 2 wt% to 8 wt%, based on derivative and non‐derivative dissolution approaches, are investigated. Three different switchable solvent systems are tested. After accessing the stability of the produced cellulose solutions, their regeneration is investigated using different alcoholic coagulation media. In order to find a suitable coagulation medium and stable cellulose solution, a dissolution–regeneration cycle is investigated, while trying to minimize the amount of waste by recovering the employed solvents. The process is optimized and the resulting fibers are characterized by infrared (IR) spectroscopy, optical microscopy, as well as scanning electron microscopy.
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