In order to obtain a novel type of thermally stable polyamides with enhanced solubility, design and synthesis of a diamine were achieved. A nicotinamide-based dichloro compound was obtained via nucleophilic substitution reaction of 2,6-diaminopyridine with 6-chloronicotinoyl chloride. The final diamine was attained through reaction of dichloro product with 5-amino-1-hydroxynaphthalene. The obtained materials were completely characterized by common spectroscopic methods and elemental analysis. Polycondensation reaction of the diamine with different diacid chlorides led to the preparation of related nicotinamide-based poly(ether amide)s. Polymers were well characterized, and their physical and thermal properties including viscosity, solubility, thermal behavior and stability, flame retardancy, and crystallinity were studied. The polymers showed high thermal stability and flame retardancy together with enhanced solubility.

A new optically active diacid (DA) was prepared by nucleophilic substitution reaction of R-(À)-mandelic acid with terephthaloyl chloride in the presence of potassium hydroxide. This DA named terephthalic acid bis(carboxyphenylmethyl) ester was used as a monomer for the preparation of related optically active polyesters. Polycondensation of DA with different aromatic diols, including hydroquinone, 1,5-dihydroxy naphthalene, 1,4-dihydroxy anthraquinone, 1,8-dihydroxy anthraquinone, 2,4-dihydroxy benzophenone, and bisphenol A, in the presence of 4-toluenesulfonyl chloride using high temperature solution method led to preparation of different polyesters. The prepared monomer and all the polymers were characterized by conventional methods. Thermal and physical properties of the polyesters, including thermal stability, thermal behavior, solution viscosity, and solubility behavior, in addition to optical activity were studied. The optically active polyesters showed high thermal stability, whereas the presence of bulky groups improved their solubility.

The main aim of this study was the preparation of modified polyureas with improved thermal stability and solubility. Accordingly, a series of aromatic/aliphatic pyridine-based polyureas was synthesized from the reaction of a novel diamine (DA) with different diisocyanates, including 4,4 0 -diphenylmethane diisocyanate, toluene diisocyanate, 1,5-naphthalene diisocyanate, and isophorone diisocyanate, by a solution polymerization route. The DA monomer was prepared via a two-step reaction. The nucleophilic substitution reaction of oxydianiline with 6-chloronicotinoylchloride led to the preparation of a diamide dichloro compound, and the subsequent reaction of this compound with 4-aminophenol resulted in the preparation of the DA. After polymerization, the structural characterization and physical properties of the polymers were examined. The resulting polymers were soluble in common polar aprotic solvents, and they showed improved thermal stabilities in comparison with common polyureas. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: 608-613, 2012

ABSTRACT:A novel diacid isophthalic acid bis-(carboxyphenyl methyl) ester (IBE) containing optically active center and bulky pendent groups was successfully synthesized and used to prepare a series of aromatic polyesters. IBE was prepared via a reaction of R-(-)-mandelic acid with isophthaloyl chloride in the presence of potassium hydroxide. Direct polycondensation reactions of this monomer with various aromatic diols using para-toluenesulfonyl chloride ( p-TsCl) via a Vilsmeier adduct resulted in the preparation of new optically active polyesters. Polyester showed reasonable molecular weight based on gel permeation chromatography (GPC) and inherent viscosity methods. Other physical and thermal properties of the polymers, including solubility, thermal behavior, thermal stability, and crystallinity in addition to optical activity, were studied. These heat-resistant polymers showed optical activity and presence of