Synthesis of New Optically Active Poly(amide-imide)s Derived from N,N - (pyromellitoyl)-bis-S-valin

Pyromellitic dianhydride (benzene-1,2,4,5-tetracarboxylic dianhydride) (1) wasreacted with s-valine (2) in acetic acid and the resulting imide-acid [N,N''-(pyromellitoyl)-bis-s-valine] (4) was obtained in high yield. The compound (4) was convertedto the N,N''-(pyromellitoyl)-bis-S-valine diacid chloride (5) by reaction with thionyl chloride. The polycondensation reaction of this diacid chloride with several aromatic diamines such as 1,4-phenylenediamine (6a), 4,4''-diaminodiphenyl methane (6b), 4,4'' diaminodiphenylsulfone (4,4''-sulfonyldianiline) (6c), 4,4''-diaminodiphenylether (6d), 2,4-diaminotoluene (6e), and 1,3-phenylenediamine (6f) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as ocresol and trimethylsilyl chloride as an activating agent for diamines. The polymerization reactions were also performed with two other low-temperature and high-temperature solution polycondensation in the presence of trimethylsilyl chloride. The polymerization reactions proceeded fast and produced a series of optically active poly(amideimide) s with good yield and moderate inherent viscosity of 0.25-0.43 dLg-1. One of the polymers (7b) showed high thermal resistance, the temperature of 5 % weight loss for (7b) was 490oC and the residual weight at 600oC was 76%. All of the above polymers were fully characterized by IR, elemental analysis and specific rotation. Some structural characterization and physical properties of these optically active poly(amide-imide)s are reported.