Viscometric behavior of liquid-crystalline solutions of hydroxypropyl cellulose in N,N-dimethylacetamide and in dimethylsulfoxide: Effects of temperature and concentration

Viscometric properties of two kinds of hydroxypropyl cellulose (HPC) solutions which exhibit liquid-crystalline behavior under certain conditions were determined by using a cone–plate viscometer. Measurements included the temperature and concentration dependences of viscosity. A phenomenological superposition for the viscosity was also tried. The viscosity for the solutions of HPC both in N,N-dimethylacetamide and in dimethylsulfoxide displayed a minimum and a maximum with respect to temperature and the specific viscosities at the minimum and the maximum decreased with increasing concentration. Concentration–temperature superposition for the viscosity of both systems could be applied over a limited concentration range. The physical interpretation is still obscure.