Studies on coagulation process for cellulose liquid crystalline solution

Liquid crystalline solutions of cellulose in phosphoric acid/poly-phosphoric acid compound solvent were prepared in a kneader.The coagulation rate was measured based on microscopic observation of the moving boundary associated with coagulation.The effect of the nature of the coagulant,temperature of coagulation bath,and cellulose concentration on the coagulation rate was studied.The results show that the molecular size and molecular structure of the coagulant play an important role in determining the rate of coagulation,coagulation rate decreases with increasing molecular volume for the three monohydric alcohols,ethanol,1-propanol and 2-propanol;an Arrhenius-type relationship exist between the coagulation rate and temperature,coagulation rate increases with increasing the temperature of coagulation bath,the activation energy for coagulation increases in the order ethanol1-propanol2-propanol;coagulation rate decreases with increasing cellulose concentration in the solution.Based on these studies,the effect of coagulation variables on coagulation process was depicted.