Synthesis and characterization of new aromatic polyamides bearing crown ethers or their dipodal counterparts in the pendant structure. I. Benzo-12-crown-4 andortho-bis(2-ethoxyethoxy)benzene

Aromatic Polyisophthalamides with Mononitro, Dinitro and Trinitroiminobenzoyl Pendant Groups

A series of aromatic polyisophthalamides containing mono-, di- and tri-nitroiminobenzoyl pendant groups were prepared from aromatic diamines and different 5-iminonitrobenzoylisophthalic acids. Interesting property relationships were revealed when evaluating the influence of the number and the position of the nitro groups in the benzoyl ring. Semi-empirical methods were used to obtain quantitative structure—property relationships (QSPR), which correlated the parameters obtained by molecular modeling with water uptake, thermal stability and 13 C and 1 H NMR chemical shifts. Moreover, by modifying the Bicerano method for aromatic polyamides, the predicted glass transition temperature ( Tg) values showed a high degree of correlation with the measured data. The polyamides registered high Tg values of up to 343°C, good thermal and mechanical properties, enhanced solubility in polar aprotic solvents, and their water uptake was as high as 19% (w/w) at 100% relative humidity.