Curing studies of a polyimide precursor. II. Polyamic acid

摘要: The cure of pyromellitic dianhydride–oxydianiline polyamic acid is compared with that a model compound, diphenylcarbamido–dicarboxy–benzene, both having been synthesized in 1-methyl-2-pyrrolidinone (NMP). Laser interferometry and thermogravimetric analysis showed that, analog to the diamic forms complexes NMP (repeat unit/NMP: 1/4 1/2). Thermal stability these was found be similar ones compound as revealed by comparison decomplexation temperature–heating rate curves. Activation energies processes for are given. Anhydride formation, reaction compete imidization, takes place also during at fairly low temperatures. molecular weight drop due chain scission resulting from anhydride formation followed viscometry.