Effect of CaCl_2 on solution properties of poly(3,3′-diphenylsulfone terephthalamide)in DMF

In order to study the effect of CaCl2 on macromolecular conformation and form of poly(3,3′-diphenylsulfone terephthalamide)(mt-PSA)in DMF,rheological behavior of concentrated solutions was studied with rheometer.Solution viscosity and coil dimension of diluted solutions were analyzed by viscosity and light scattering measurements.Addition of CaCl2increased specific viscosity(ηsp)of concentrated solutions,and increased intrinsic viscosity([η])and hydrodynamic radius(Rh)of dilute solutions due to the interaction between macromolecule and solvent.The mt-PSA chain extended with the addition of CaCl2.However,the weight-average molecular weight(Mw)of mt-PSA had no significant change by addition of CaCl2.This would indicate that the conformation of macromolecule did not collapse or aggregate.