Synthesis, characterization, and thermal degradation of new aromatic poly(azomethine-urethane)s and their polyphenol derivatives

Abstract

A new polyurethane was synthesized by condensation reaction of 2,4-dihydroxy benzaldehyde (DHB) with methylene-di-p-phenyl-diisocyanate (MDI) under argon atmosphere. The synthesized polyurethane was converted to its poly (azomethine urethane) species (MP-2AP, MP-3AP, and MP-4AP) by graft copolymerization reactions with amino phenols (2-amino phenol, 3-amino phenol, and 4-amino phenol). Obtained poly(azomethine urethane)s (PAMUs) were converted to their polyphenol species (P-MP-2AP, P-MP-3AP, and P-MP-4AP) by oxidative polymerization reaction (OP) using NaOCl as the oxidant. The structures of the obtained compounds were confirmed by FT-IR, UV-vis, 1 H-NMR, and 13 C-NMR techniques. The molecular weight distribution parameters of the synthesized compounds were determined by the size exclusion chromatography (SEC). The synthesized compounds were also characterized by solubility tests, TG-DTA, and DSC analyses. Thermal decomposition steps at various temperatures were clarified by FT-IR analyses of degraded products. Fluorescence measurements were carried out in various concentrated DMF solutions to determine the optimum concentrations to obtain the maximal PL intensities.

Fluorescence, thermal and electrochemical properties of poly(azomethine-urethane)s containing sulfone group

“…At the FT-IR spectral data of SS, azomethine (-CH=N) and hydroxyl (-OH) peaks are observed at 1653 and 3371 cm -1 , respectively. According to FT-IR spectral data of TDI, MDI, and HMDI, characteristic diisocyanate -N=C=O peaks are observed at 2230, 2265, and 2250 cm -1 , respectively, which agrees with the literature [24,26]. According to Table 2, hydroxyl (-OH) group at SS, -N=C=O stretch vibrations of the diisocyanates (TDI, MDI, and HMDI) disappear due to urethane formation.…”

“…The temperature increased at 110°C and the reaction mixture was stirred under nitrogen for 5 h and left overnight for the completion of the reaction. The obtained PAZUs were washed with methanol (25 mL) and THF (25 mL) to remove the unreacted components [24,25]. The polymers were dried in a vacuum oven at 70°C for 36 h. The yields of SS-TDI, SS-MDI, and SS-HMDI were found as 87, 83, 88, and 88 %, respectively.…”

“…Also, aliphatic protons of SS-HMDI are observed between 1.22 and 3.04 ppm. NMR analyses results indicate the formation of polymers[24,28].…”

Accelerated thermal ageing studies of polydimethylsiloxane (PDMS) rubber

“…Thermal ageing mechanisms for polydimethylsiloxane Thermal degradation of polymeric materials have long been of great interest both in academic and industrial perspective [1][2][3].…”

Thermal, fluorescence, and electrochemical characteristics of novel poly(urethane-imide)s

“…Most of the reported approaches are based on copolymerization or blending with other polymers of high thermal stability such as polyimides, [3][4][5][6] polyurea, [7,8] polyamide, [9,10] and polyazomethine. [11] Polyimides are high-performance polymers because of their high thermal and thermo-oxidative stabilities, high transition temperatures, and chemical resistance, insulating, and excellent mechanical properties. Therefore, polyimides have been widely used in many applications such as aerospace, microelectronics, optoelectronics, and information industries.…”