Dielectric relaxation study of hexamethylphosphoramide–1,4-dioxane mixtures using time domain reflectometry (TDR) technique

Abstract

Dielectric relaxation study on hexamethylphosphoramide–1,4-dioxane binary mixtures has been carried out at 16 concentrations over the frequency range of 10 MHz to 30 GHz at different temperatures using time domain reflectometry technique. The mixtures exhibit a principal dispersion of the Debye relaxation type at microwave frequencies. The concentration-dependent static dielectric constant, excess dielectric properties and thermodynamic parameters have been determined. The hydrogen-bonded theory is applied to compute the Kirkwood correlation factors for the mixture. The average numbers of the hydrogen bonds between hexamethylphosphoramide–hexamethylphosphoramide and hexamethylphosphoramide–1,4-dioxane pairs are estimated from the dielectric constant.

Keywords:

• dielectric permittivity
• relaxation time
• time domain reflectometry
• hexamethylphosphoramide

Acknowledgements

The financial support from the Department of Science and Technology (DST), New Delhi is thankfully acknowledged (project no. SR/S2/LOP-25/2007). G.R. Mahajan thanks Swami Ramanand Teerth Marathwada University, Nanded for making the laboratory facility available.