Intrinsic viscosity and molecular weight measurement of nylon 66 polymers

Intrinsic viscosity of several nylon 66 polymers in the molecular weight range 25,000–105,000 was measured in hexafluoroisopropanol (HFIP). The experimentally measured viscosity was compared with the data obtained by least-squares fit of the classical equations of Huggins and Kraemer. The utility of the single-point viscosity measurement is also discussed and compared with the measured data. The apparent hydrodynamic parameters obtained from the Huggins equation indicate the applicability of HFIP for studying polyamide polymers. The molecular weight of these polymers was also determined by the gel permeation and low-angle laser light scattering technique (GPC–LALLS). The molecular weight data combined with the viscosity data provide the Mark–Houwink parameters. The agreement between these parameters and the same parameters obtained in tetrafluoropropanol (TFP) is excellent.