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Synthesis, characterization, and properties of a new polyurethane elastomer based on tragacanth gum polysaccharide

This study prepared a type of bio-based elastomeric polyurethane from tragacanth gum (TG). TG is a natural polysaccharide with many hydroxyl groups that can be used as a chain extender and a crosslinker to react with the isocyanate groups in polyurethane prepolymer to form a highly branched and crosslinked polyurethane with high molecular weight and good mechanical properties. The chemical structure of the prepolymer and the thermal and mechanical properties of the prepared polyurethane were studied by Fourier transform infrared, nuclear magnetic resonance, scanning electron microscopy, thermal gravimetric analysis, dynamic mechanical thermal analysis, and tensile strength tester. The properties of the polyurethane-based on TG (TG-PU) were compared with the properties of the PU based on only polyethylene glycol. The TG-PU sample with 0.5 g TG showed a tensile strength of 288% and the glass transition temperature (Tg) of 33% higher than the tensile strength and Tg of PU without TG. We expect these findings to widen the range of preparation and applications of bio-based polyurethane materials. Graphical Abstract