Effect of Sorbed Water on Dielectric Dispersion of Cellulose at Low Frequencies

Abstract

Real and imaginary parts of dielectric constant are measured at frequencies from 80 c/s to 120 kc/s for printing paper and cellophane with varied water content. Dielectric dispersion at low frequencies is observed above the critical water content, 3% for printing paper and 6% for cellophane. The intensity of dispersion increases and the logarithm of loss maximum frequency decreases both linearly with increase of water content above this critical value. From these results and others, it is concluded that the low frequency dispersion of cellulose may be attributed to the rotational segmental motions of cellulose which start through the sorbed water molecules breaking the intra- and intermolecular hydrogen bonds.
Dielectric dispersion of cellulose triacetate is also studied, the results being essentially similar to cellulose.