Synthesis and characterization of novel thermally stable poly(ether-amide)s containing dinaphthosulfone units in the main chain

Abstract

Abstract A New type of sulfone (4) containing 1,1´-thiobis(2- hydroxynaphthalene) diacid as a monomer was synthesized from the reaction of 2-hydroxynaphthalene (1) and sulfur dichloride, followed by reaction with methylchloroactate to obtain diester (2). Oxidation of this product in the presence of hydrogen peroxide followed by basic hydrolysis led to corresponding sulfone diacid (4) in good yield. Six organic-soluble poly(ether-amide)s bearing sulfone groups were synthesized via direct polycondensation of diacid (4) with commercially available aromatic diamines in the presence of calcium chloride as dehydrating agent. The resulting polyamides had inherent viscosity ranging from 0.38 to 0.46 dLg-1 at concentration of 0.5 gdL-1 in N,N-dimethylacetamide at 30 °C. The glass transition temperatures of these polyamides were recorded between 276-327 °C in air atmosphere. These polymers were also characterized by IR, 1H NMR and elemental analysis and their physical properties including viscosity, solubility properties, thermal stability and thermal behaviour were studied. These polyamides showed very good thermal stability and solubility in polar aprotic solvents.