INFLUENCE OF THERMAL HISTORY ON THE FORMATION OF LIQUID-CRYSTALLINE PHASE OF HYDROXYETHYL CELLULOSE-ACETATE

The influence of thermal history on the formation of HECA liquid cryst alline phase was studied by DSC. It was found that the degree of order ing in the liquid crystalline phase was heterogeneous, and the multiph ase transformation appears when the liquid crystalline phase transform ed to the isotropic one. When HECA was annealed in the liquid crystall ine state, the parts with the lower degree of ordering could transform to ones with the higher degree of ordering, and the temperature and t he enthalpy of the phase transformation from the liquid crystalline ph ase to the isotropic phase increased. (C) 1998 John Wiley & Sons, Inc.