RHEOLOGICAL BEHAVIOR OF POLY[N,N'-(4,4'-OXYDIPHENYLENE)PYROMELLITAMIDO ACID] SOLUTIONS

The molecular characteristics of poly[N,N'-(4,4'-oxydiphenylene)pyrome llitamido acid] samples synthesized under laboratory and semicommercia l conditions were studied by viscometry, light scattering, and gel per meation chromatography, anal the viscosity of their concentrated solut ions in dimethylformamide (DMF) was measured as a function of concentr ation and time. The strain-strength characteristics of films cast from these solutions and imidized under standard conditions were evaluated , and the correlations between these characteristics and synthesis con ditions were estimated.