Aromatic polyamides and polythioamides with pendent chlorobenzylidine rings were synthesized through direct polycondenzation of 2-(p-chlorobenzalimino) terephthalic acid with the diamines 4,4′-oxidianiline (1a), 4,4′-methylenediamide (1b), 4,4′-diaminodiphenyl sulfone (1c), and thioamines 4,4′-(bisthiourea) diphenyl ether (3a), 4,4′-(bisthiourea) diphenyl methane (3b), 4,4′-(bisthiourea) diphenyl sulfone (3c), respectively, in DMF using P(OPh)3/pyridine. The polymers were precipitated using water as nonsolvent. FTIR and 1H-NMR spectroscopic analysis was used to characterize the monomers and polymers. Representative polyamides and polythioamides were used for the removal of heavy metal ions such as Pb(II), Cd(II), Cu(II), and Cr(III) from aqueous solutions. The effects of pH, contact time, and initial concentration on the uptake of metal ions have been investigated. The adsorption capacities under competitive conditions were in the order Pb (II) > Cu (II) > Cr (III) > Cd (II). The adsorbed ions were eluted by treatment with 2N HCl, and the activities of the polymers are retained after fourth regeneration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Synthesis, characterization, and heavy metal ion adsorption studies of polyamides, polythioamides having pendent chlorobenzylidine rings

Recently, soluble poly(azomethine ester)s with good thermal stability and liquid crystalline properties are much sought after in opto-electronic field. One such attempt was to synthesize poly(azomethine ester)s with a pendent group. In this study, the newly synthesized diacid monomer benzalaniline 3’-4’dimethoxy terepthalic acid was condensed with two diol monomers to get the polymers with pendent benzylidene group. The diacid monomer was characterized by UV, IR, NMR and CHNS analysis. The polymers were characterized by IR, TGA, and for liquid crystalline property. Polymer-I showed the highest thermal stability upto 335°C. Polymer-II exhibited liquid crystalline nature along with good solubility and thermal stability.

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Synthesis and Characterization of Poly(azomethine ester)s with a Pendent Dimethoxy Benzylidene Group

In this study, the novel Schiff base monomers were synthesized by condensation reactions. Then, these monomers were converted to poly(azomethine-ether)s by oxidative polycondensation (OP) reactions in an aqueous alkaline medium. The structural characterizations of compounds were carried out by FT-IR, NMR, and size exclusion chromatography (SEC). According to the SEC analysis, the calculated number-average molecular weight (Mn), weight average molecular weight (Mw), and polydispersity index values of P-2 and P-4 were found to be 17,500 g mol−1, 24,400 g mol−1, and 1.39; and 18,700 g mol−1, 25,600 g mol−1, and 1.36, respectively. The HOMO-LUMO energy levels, electrochemical (), and optical (Eg) band gaps of polymers were calculated from cyclic voltammetry (CV) and UV–vis measurements, respectively. CV was used to determine the electrochemical oxidation–reduction characteristics of polymers. Thermal characterizations of compounds were made by using TG-DTA and DSC techniques. According to TG analysis, polymer...

https://www.tandfonline.com/doi/pdf/10.1080/15685551.2013.867581

Synthesis, characterization, optical, and electrochemical properties of thermal stable novel poly(azomethine-ether)s

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, 1H-NMR, and 13C-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.

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

The preparation, characterisation, thermotropic and optical properties of low-molecular azomethines with or without methoxy side group are described in this paper. The azomethine compounds were synthesised by condensation reaction of o-dianisidine/benzidine with para-halogen substituted benzaldehyde. Their properties were analysed by differential scanning calorimetry, thermogravimetry analysis, polarised optical microscopy, X-ray diffraction and optical spectroscopy. The azomethines present liquid crystalline behaviour with large mesophase range and high thermal stability. The compounds without lateral methoxy groups showed smectic A phase, while those with methoxy groups exhibited only nematic phase. The effect of methoxy group and different terminal substituents on the mesomorphic behaviour, molecular and optical properties was estimated in terms of parameters such as molecular polarisability, dipole moment, interdigitation parameter and axial ratio.

J. Rajeshkumar

Papers

Synthesis, characterization and electrical conductivity of new poly (azomethine ester)s from hydroxy acids