Synthesis of ordered polymer by direct polycondensation .7. Ordered poly(acylhydrazide-amide)

An ordered (-aadcbbcd-) poly(acylhydrazide-amide) was prepared by the direct polycondensation of a pair of symmetric monomers (XabX), 2,5-dimethylterephthalic acid (XaaX) and 4,4'-(oxydi-p-phenylene)dibutanoic acid (XbbX), with a nonsymmetric monomer (YcdY), 4-aminobenzhydrazide, using the condensing agent diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)pho (1). The polymerization was carried out by mixing the dicarboxylic acids, condensing agent 1, and triethylamine (TEA) in NMP for 2 h at room temperature, followed by adding 4-aminobenzhydrazide, yielding the ordered poly(acylhydrazide-amide) with an inherent viscosity of 0.40 dL/g. The authentic ordered polymer was prepared to verify the structure of the ordered polymer. The microstructures of polymers obtained were investigated by C-13-NMR spectroscopy, and it was found that the polymer had the expected ordered structure. Furthermore, the model reactions were studied in detail to demonstrate the feasibility of polymer formation.