“Bishydrazid A2”: A new semiaromatic film and fiber-forming polymer based on bisacid A2

We report the preparation of the dihydrazide of bisacid A2 (“bisdihidrazide A2”). Its composition and structure have been verified by elemental analysis and by means of infrared and NMR spectra. This material was then converted into a polyhydrazide (“bishydrazid A2”) in an HCl-accepting solvent. The polymer was converted to fiber by wet spinning the dope obtained during the polycondensation reaction without prior neutralization or dilution. Film was cast from a solution of the precipitated and washed polymer which had an inherent viscosity of about 0.8; mechanical tests on the film—both before and after treatment with formic acid—were carried out. Differential scanning calorimetry showed an α/β transition comparable to that shown by bisacid A2 polyaramides and described in preceding papers^1,2. Wide-angle x-ray scattering showed that the polymer is amorphous. Scanning electron micrographs revealed the physical structure of wet-spun fiber and the probable mechanism of fiber formation by dope extrusion into a water bath.