NON-NEWTONIAN FLOW OF SOLUTION OF HIGH MOLECULAR WEIGHT POLYMER IN EXTREMELY VISCOUS SOLVENTS

摘要

Recent theoretical work has predicted that the intrinsic viscosity of very long chain polymers in viscous solvents should increase with increasing shear gradient. Highly viscous solvents are required to develop sufficient shearing forces to overcome the inner viscosity (rigidity) of the polymer coil. This report concerns experimental work directed toward examination of the theory. Two polyphenylene oxide fractions, 1.29 x 10 and 3.45 x 10 molecular weight, in parylene and two polyisobutylene fractions, 6.0 x 10 and 1.85 x 10 molecular weight, in paraffin oil, were measured in precision equipment which covered five velocity gradient ranges. The maximum 2 shear stresses for pure water, paraffin oil and parylene are 640, 2600 and 3900 dynes/cm . In these solvents no increase in intrinsic viscosity, as predicted, was observed. Although more information is required before the theory can be fully evaluated, it is suggested that the proposed treatment of gradient dependence does not take into account sufficiently the inner viscosity of the macromolecular coil and anisotropic hydrodynamic interaction.