Preparation and characterization of new optically active poly(amide imide)s derived from N,N′-(4,4′-sulphonediphthaloyl)-bis-(s)-(+)-valine diacid chloride and aromatic diamines under microwave irradiation

The present paper is an extension of microwave method describing the synthesis of the new optically active poly(amide-imide)s. The main focus of this work is the design of new effective microwave method for preparing optically active poly(amide-imide)s. Imide-acid (3) was synthesized by the reaction of 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (1) with (s)-(+)-valine (2) in acetic acid. The compound 3 was coverted to diacid chloride 4 by reaction with excess amount of thionyl chloride. Polycondensetion reaction of diacid chloride 4 with several aromatic diamines such as 4,4'-sulfonyldianiline (5a), 4,4'-diaminodiphenyl methane (5b), 4,4'-diaminodiphenylether (5c), p-phenylenediamine (5d), m-phenylenediamine (5e), 2,4-diaminotoluene (5f) and 4,4'-diaminobiphenyl (5g) was carried out in the presence of small amount of o-cresol under microwave irradiation as well as conventional heating method. We obtained a series of optically active poly(amide-imide)s with high yield and inherent viscosity ranging from 0.22-0.35 dL/g. These new polymers were characterized by FT IR, H-1 NMR, elemental analyses and specific rotation techniques.