Preparation and characterization of optically active and organosoluble poly(amide-imide)s from polycondensation reaction of N,N′-(4,4′-sulphonediphthaloyl)-bis-L-isoleucine diacid with aromatic diamines

3,3 ',4,4 '-Diphenylsulfonetetracarboxylic dianhydride (1) was reacted with L-isoleucine (2) in acetic acid and the resulting imide-acid (3) was obtained in high yield. The diacid chloride (4) was prepared from the diacid derivative (3) by reaction with thionyl chloride. The polycondensation 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 performed by two conventional methods: low temperature solution polycondensation and short period reflux conditions. In order to compare conventional solution polycondensation reaction methods with microwave-assisted polycondensation, the reactions were also carried out under microwave conditions with a small amount of o-cresol that acts as a primary microwave absorber. The reaction mixture was irradiated for 6 min with 100% of radiation power. Several new optically active poly(amide-imide)s with inherent viscosity ranging from 0.23 to 0.41 dl/g were obtained with high yield. All of the earlier polymers were fully characterized by IR, elemental analyses and specific rotation techniques. Some structural characterizations and physical properties of these new optically active poly(amide-imide)s are reported. Copyright (c) 2005 John Wiley & Sons, Ltd.