PREPARATION AND DIELECTRIC-PROPERTIES OF CELLULOSE DERIVATIVES WITH HIGH-POLARITY SUBSTITUENTS

An attempt was made to prepare highly dielectric polymers from O-(2,3- dihydroxypropyl)cellulose (DHpC)b) by cyanoethylation, nitrobenzoylati on, cyanobenzoylation, and trifluoroacetylation. To accomplish this, D HPC samples with different molar substitution (MS) were prepared by ho mogeneous dihydroxypropylation of cellulose with glycidol in a 10 wt.- % LiCl/DMA solvent system. Among the sample derivatives, all of which are soluble in various organic solvents, the cyanoethylated derivative s with high MS values have dielectric constants higher than 30 at room temperature and 1 kHz. These derivatives also form cholesteric liquid -crystalline (LC) phases in a wide temperature range, but the dielectr ic constant is independent of the phase structure. The results are dis cussed in terms of the structural difference among the sample polymers .