Synthesis of new optically active poly(amide-imide)s containing EPICLON and L-phenylalanine in the main chain by microwave irradiation and classical heating

EPICLON [3a,4,5,7a-Tetrahydro-7-methyl-5(tetrahydro-2,5-dioxo-3-furanyl)-1,3-isobenzofurandione] or [5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexyl-1,2dicarboxylic acid anhydride] (1) was reacted with L-phenylalanine (2) in acetic acid, and the resulting amic acid was refluxed under a Dean-Stark system with benzene, which produced diacid (3) in high yield. Compound (3) was converted to the diacid chloride (4) by reaction with oxalyl chloride in dry carbon tetrachloride. The polycondensation reaction of this diacid chloride (4) with several aromatic diamines such as 4,4'-sulfonyldianiline (5a), 4,4'-diaminodiphenylmethane (5b), 4,4'-diaminodiphenylether (5c), 1,4-phenylenediamine (5d), 1,3-phenylenediamine (5e), 2,4-diaminotoluene (5f), and 1,5-diaminonaphthalene (5g) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as N-methylpyrrolidone (NMP). The polymerization reactions were also performed under two different classical heating methods: low temperature solution polycondensation in the presence of trimethylsilyl chloride, and high temperature polymerization. A series of optically active poly(amideimide)s with moderate yield and inherent viscosity of 0.14-0.22 dL/g were obtained. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of this optically active poly (amide-imide) s are reported. (C) 2004 Wiley Periodicals, Inc.