Aromatic polyamides with pendent acetoxybenzamide groups and thin films made therefrom

New aromatic polyamides containing 1,3,4-oxadiazole or benzonitrile units in the main chain and 5-(4-acetoxybenzamido) groups in the side chain have been synthesized and their properties have been characterized and compared with those of related polyamides and polyoxadiazole-amides. These polymers show good thermal stability, with initial decomposition temperature being at about 300 °C and glass transition temperature in the range of 260-280 °C. They are easily soluble in certain solvents such as N-methylpyrrolidinone (NMP), N,N^′-dimethylacetamide (DMA) and N,N^′-dimethylformamide (DMF) and can be cast from solutions into thin flexible films. The polymer films had tensile strengths in the range of 77-97 MPa, tensile moduli in the range of 2.3-2.6 GPa and elongation at break values ranging from 6% to 24%. One of the polymers containing the 1,3,4-oxadiazole ring exhibited blue fluorescence.