Abstract

EVALUATION OF THERMOACOUSTICAL PARAMETERS OF DEXTRAN WITH (1N) SODIUM HYDROXIDE USING ULTRASONIC TECHNIQUE AT DIFFERENT TEMPERATURES AND CONCENTRATIONS

*Subhraraj Panda, Md. Mikail Faruqui, Asit Ku. Dhal, Udit Pratap Gahir and Tapaswi Ku. Bal

ABSTRACT

Ultrasonic investigation of molecular interactions of polymer dextran with aqueous sodium hydroxide is carried out at different temperatures (303K, 308K, 313K, 318K & 323K) at frequency 5MHz. The experimental measured values of density (ρ), viscosity (η) and ultrasonic velocity (U) of the solutions has been used to compute the different acoustic parameters like free volume (Vf), internal pressure (Пi), absorption coefficient or attenuation coefficient (α), Rao’s constant (R) and Wada’s constant (W) have been calculated at constant frequency. These acoustic parameters are used to access and explain the nature and strength of molecular interaction of dextran with sodium hydroxide. The variation of these parameters with respect to concentration and temperature has also been studied which throws light into the structural rearrangement of solute and solvent in aqueous solution. It is found that the solute-solvent interaction depends on concentration, temperature, ionic size, ionic field strength and nature of the ion. Some possible reasons on the increase or decrease of acoustic and thermodynamic parameters with temperatures change are presented.

Keywords: Aqueous dextran, free volume, internal pressure, attenuation coefficient, Rao’s constant and Wada’s constant.