THERMAL-BEHAVIOR OF FLUORINATED AROMATIC POLYETHERS AND POLY(ETHER KETONE)S

Eight amorphous polyethers and poly(ether ketones) were synthesized an d characterized by gel permeation chromatography, thermogravimetric an alysis, differential scanning calorimetry, and dynamic mechanical ther mal analysis. Polymers containing bulky, cyclic 2,2'-biphenyl side gro ups were found to have the highest glass transition temperatures, were more thermally stable and exhibited the highest intramolecular barrie rs to rotation. Incorporation of perfluorophenylene groups resulted in internal plasticisation and a relative lowering of T-g. The steepness of cooperativity plots determined from Williams-Landel-Ferry shift fa ctors correlated with the rigid nature of the polymer chains, but not with the broadness of the relaxation (characterized by the Kohlrausch- Williams-Watts stretch exponent beta) as predicted by the coupling mod el. A beta-process observed in the polymers containing cyclic biphenyl side groups was similar in appearance to a typical ''structural'' rel axation. The position, intensity, and breadth of the gamma-process was sensitive to chemical structure and absorbed moisture.