MEASUREMENTS OF VELOCITY PROFILE DEVELOPMENT IN THE SPINNING FLOWS OFLIQUID-CRYSTALLINE POLYMER-SOLUTIONS

The development of velocity profile inside a filament was studied for spinning flows of LCPs using a hydrogen-bubble method. Both isotropic (33 wt%) and Liquid crystalline (50 wt%) aqueous solutions of hydroxyp ropylcellulose were used as the test fluids. The velocity profile for the 33 wt% solution varies from a convex profile to a uniform one simi lar to that for Newtonian fluids. For the 50 wt% solution, however, an anomalous profile of the velocity, that is a concave profile, is foun d beyond a distance of one radius of the nozzle downstream from the ex it. Since this concave profile persists far downstream from the nozzle exit, it may affect the molecular orientation distribution inside a f iber. (C) 1997 The Society of Rheology.