Curing studies of a polyimide precursor

Complexes between diphenylcarbamido‐dicarboxybenzene and 1‐methyl‐2‐pyrrolidinone, 1/4 and 1/2 M, are obtained by reacting pyromellitic dianhydride with aniline in the solvent 1‐methyl‐2‐pyrrolidinone. Decomplexation and imidization of this diamic acid are studied by thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectrometry, polarizing microscopy, and gas chromatography/mass spectrometry. Side reactions competing with the imide formation are discussed. The presence of solvent is found to markedly influence imidization. Copyright © 1987 John Wiley & Sons, Inc.