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    Synthesis And Characterization Of Novel 1,2,3-Triazole-Bridged Oxime Polyurethanes Obtained From An Isomannide Derivative
    (Macedonian Journal of Chemistry and Chemical Engineering, 2021) Bayrak, Fatih; Oral, Ayhan; Ay, Kadir
    Polyurethanes (PUs) are synthesized by the reaction of diisocyanates and diols and are widely used in furniture foams, thermal insulation, coatings, and adhesives. In this work, a 1,2,3-triazole-bridged dioxime (compound 6) as a diol source was synthesized from isomannide via tosylation, azidation, and cyclization-addition and used in the syntheses of new PUs. A new carbohydrate-based linear P-1 was syn-thesized by the reaction of 6 and 1,6-hexamethylene diisocyanate (1,6-HMDI). Besides, three new linear PUs (P-2, P-3, and P-4) were synthesized by the reaction of 6, isomannide compound (used in different molar ratios), and 1,6-HMDI. The thermal properties of the new PUs were determined by thermogravime-try (TG), their molecular structures were characterized by FTIR, 1H- and 13C-NMR, and the molecular weights of some polymers were determined by GPC/SEC. Additionally, the surface characteristics of the synthesized PUs were examined via scanning electron microscopy (SEM).
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    Synthesis of 1,2,3-triazole group-containing isomannide-based aromatic new polyurethanes
    (Springer Science and Business Media Deutschland GmbH, 2022) Bayrak, Fatih; Ay, Emriye; Oral, Ayhan; Karayıldırım, Tamer
    Ten new carbohydrate-based aromatic polyurethanes have been synthesized using isomannide and/or a new 1,2,3-triazole isomannide derivative, IV, as the diol source in the polymerization reactions. As the isocyanate source, 1,4-phenylene diisocyanate or 2,4-toluene diisocyanate was used. To synthesize compound IV, isomannide was tosylated, the tosyl groups were substituted with azide, the triazole ring was formed by reaction with 2,4-pentane dione and finally carbonyl groups were converted into oximes. The synthesis of copolymers and terpolymers was performed using different proportions of diisocyanate and diol sources in DMF. The structural elucidation of the synthesized compounds and polymers was performed using spectroscopic techniques such as FTIR, 1D- and 2D-NMR and HRMS. The thermal behaviour and molecular weight distribution of polymers were analyzed by thermal gravimetric analysis and gel permeation chromatography, respectively. The surface properties of the polymers were analyzed using scanning electron microscopy. A comparative study on thermal behaviour of the synthesized polymers showed that polymers containing a higher amount of compound IV displayed better thermal stability. The average molecular weights of copolymers were observed to vary from 7,900 (PUR-3) to 21,000 (PUR-4) whereas for terpolymers, values of 19,000 (PUR-5), 5,100 (PUR-6), 22,000 (PUR-8) and 28,000 (PUR-9) were found. The diisocyanate source was found to have more effect on the surface properties of polymers than the diol source: when 2,4-toluene diisocyanate was used in polymer synthesis, the resultant polymers had a spongy morphology with cavities while a polymer matrix containing spheres and platelets was obtained when 1,4-toluene diisocyanate was used.