EFFECT OF THE REACTION CONDITIONS ON THE PROPERTIES OF POLY(4,4'-DIPHENYLETHER-1,3,4-OXADIAZOLE)S

Poly(4,4'-diphenylether-1,3,4-oxadiazole)s have been prepared by polyc ondensation of 4,4'-diphenylether dicarboxylic acid and hydrazine sulp hate, HS, in poly(phosphoric acid), PPA, under different reaction cond ictions. The products were characterized by viscometry, gel permeation chromatography, H-1-NMR spectrometry and thermogravimetric analysis. Dense membranes have been prepared and submitted to gas transport and wide angle X-ray diffraction, WAXD, experiments. The differences found in permeability and selectivity parameters, as well as in density and WAXD results, are discussed in terms of their solution viscosities an d hydrazide repeat unit contents.