HYDROXYETHYLCYANOETHYLCELLULOSE - A THERM OTROPIC MESOGENIC POLYMER

DSC and X-ray diffraction studies and polarization optical microscopy demonstrate that hydroxy-ethylcyanoethylcellulose (a mixed cellulose e ther) shows thermotropic mesogenic LC order in melt. This order is ret ained in the glassy state. Between 120 and 220 degrees C, the theologi cal behavior of the polymer melts is some what similar to that of othe r LC polymers. For example, theological curves are characterized by yi eld value that decreases with an increase in temperature. However, in contrast to other LC polymers, in a certain temperature range (150 - 1 70 degrees C), the yield value is virtually constant. In addition, the melts are characterized by very long times for structure recovery aft er the steady flow has been stopped. The fact that LC order is observe d at relatively low degrees of etherification with ethylene oxide is e xplained by the fact that incorporation of cyanoethyl groups makes the macromolecules stiffer and enhances interchain interaction.