THE LIQUID-CRYSTALLINE STATE OF WATER-SODIUM CELLULOSE SULFATE SYSTEMS STUDIED BY DSC AND WAXS

The liquid crystal formation of sodium cellulose sulphate (NaCS)-water systems was investigated by differential scanning calorimetry (DSC), polarizing light microscopy (POL) and wide-angle X-ray diffractometry (WAXS). The liquid crystalline state was observed at a water content ( W-c) ranging from 0.4 to 1.5 (g water)/(g NaCS) (g/g), and at a temper ature ranging from 260 to 310 K depending on W-c. DSC and WAXS data in dicated that each sodium ion is sandwiched by two cellulose molecules coexisting with 4-20 water molecules in the liquid crystalline state. When W-c exceeds the critical value, free water molecules enhance the molecular movement of NaCS and molecular chains are arranged in a rand om form.