SOLUTION CHARACTERIZATION OF POLYAMIC ACIDS AND POLYIMIDES.

The low dielectric constant, ease of processing, and high temperature stability of polyimide materials have led to the widespread use of these materials as insulating layers in electronic devices. Several characteristics of these materials are not yet well understood, such as the instability of solutions with time, structural changes on curing, and polyelectrolyte effects observed in dilute and concentrated solutions. These and other characteristics of the polyamic acid and polyimide formed from the condensation of pyromellitic dianhydride and 4,4 prime -diaminodiphenylether have been investigated. The polyamic acids were studied in solution using various solvents, and the cured polyimide was studied in concentrated sulfuric acid. Techniques used included low-angle light scattering, osmometry and viscometry.