The thermomechanical behavior (less than 1 Hz) of a newly available, high temperature, aromatic polysulfone has been investigated by the technique of torsional braid analysis (TBA). Speculations concerning the synthesis and structure are discussed in terms of NMR and infrared spectroscopy, elemental analysis, and a review of the general literature on polysulfones. In addition to the glass transition at 287"C, a secondary relaxation was detected in the glassy state at -100°C by a mechanical loss maximum and change in modulus. The stability of the polysulfone at elevated temperatures in air and nitrogen as monitored by TBA, DTA, and TGA is reported. The influence of heat to 500°C, high doses of ionizing radiation, and water on the transitions of the polymer is discussed. 1183

Solution properties were determined for the poly(amide acid amine) obtained from the room‐temperature polymerization of pyromellitic dianhydride with 3,3,‐diaminobenzidine in aprotic solvents. Membrane osmometry data, viscosity studies, solution aging studies, and pH–viscosity relationships were given. Anomalous upswings in viscosity–concentration plots were attributed to absorption or capillary wall effects and not to polyelectrolyte effects, such as were induced by addition of strong bases. Similar absorption effects were found with polyamic acid solutions, in contrast to earlier reports that these polyimide precursors were polyelectrolytes. Unfavorable storage characteristics of the polymer solutions were explained by aging studies which showed that at 25°C dilute solutions exhibited a rapid drop in viscosity; in concentrated solution a slow increase to gelation was observed.