DIELECTRIC INVESTIGATION OF ISOTROPIC AND ANISOTROPIC SOLUTIONS OF HYDROXYPROPYL CELLULOSE IN DIOXAN

The dielectric behaviour of hydroxypropyl cellulose in dioxan has been studied at 10-50-degrees-C over a range of concentration of 10-55 wt% to include the isotropic and anisotropic phases. The study showed tha t the loss maximum epsilon(max)'', magnitude of polarization epsilon0 - epsilon(infinity), relaxation time 1/2pif(m), degree of broadening o f the absorption curves 1 - h or alpha, and the mean-square dipole mom ent [gmu2], steadily increase with concentration up to 42wt%, above wh ich a rapid decrease takes place. This indicates that the isotropic so lution transforms to an anisotropic solution with a smaller mean dipol e moment. The critical concentration is realized to be temperature inv ariant. This was evidenced by measuring the refractive index of soluti ons covering the same concentration and temperature ranges.