Microwave-assisted synthesis of isosorbide-derived diols for the preparation of thermally stable thermoplastic polyurethane

Abstract

In order to prepare thermally stable isosorbide-derived thermoplastic polyurethane, the synthesis of two new chiral exo–exo configured diols, prepared from isosorbide, and two types of diphenols (bisphenol A and thiodiphenol) was described. The synthesis conditions were optimized under conventional heating and microwave irradiations. To prove their suitability in polymerization, these monomers were successfully polymerized using 4,4′-diphenylmethane diisocyanate (MDI) and hexamethylene diisocyanate (HDI). Both monomers and polymers have been studied by NMR, FT-IR, TGA, DSC; intrinsic viscosity of polymers has also been determined. The results showed the effectiveness of the synthetic strategy proposed; moreover, a dramatic reduction of the reaction time and an important improvement of the monomers yield using microwave irradiation have been demonstrated. The monomers, as well as the polymers, showed excellent thermal stability both in air and nitrogen. It was also shown that the introduction of sulphur in the polyurethane backbone was effective in delaying the onset of degradation as well as the degradation rate.

Electro-thermal properties and characterization of the flexible polyurethane-graphene nanocomposite films

“…The chemical shifts of other methylene groups in HDI part are observed at 0.70-1.30 ppm. The peaks are compatible with literate [66][67][68][69]. According to FTIR and 1H-NMR results, it could be obvious that the desired PU nanocomposites had been successfully made.…”

Influence of the chemical structure of diisocyanate on the electrical and thermal properties of in situ polymerized polyurethane–graphene composite films

“…The presence of these peaks is consistent with the reports in the literature. 66–69 It is clear from the FTIR and 1 H-NMR data that the desired PU nanocomposites were created effectively.…”

Synthesis and Physicochemical Properties of UV-Curable Palm Oil-Based Polyurethane Reinforced with Fluoroacrylate Monomer

“…Carbon signals (c, j) at 165.22-172 ppm range were detected as carbonyl in ester and ester-urethane functions, NHCOO units respectively [23]. Distinctive signals (k, f, h, i) coming from carbon atoms of POPU sequence (70 ppm), urethane-ester linked to quaternary nitrogen (69 ppm), ester-urethane (60 ppm) groups [24]. There were also carbon signals (m, l, d, g, e) that were responsible for the alkyl chain linked to quaternary nitrogen (41.56-47.46 ppm), isophorone ring (36.30-23.31 ppm), and methyl of methacrylate (22.18 ppm) [25].…”