SOLVENT EFFECT ON THE CONFORMATION IN SOLUTION OF 2 POLYIMIDES

The dilute solution properties of two polyimides have been studied usi ng size exclusion chromatography, light scattering and viscometry in v arious solvents. Molecular parameters (conformation and aggregation) a re found to be solvent dependent. Addition of a non-solvent (H2O) to 6 FDA-mPDA, a fluorine-containing polyimide, or Ultem a polyetherimide, in the good solvent N-methyl-2-pyrrolidone is responsible for an incre ase in molecular weight. This is attributed to aggregation of polyimid es in these conditions.