Temperature and Frequency Dependence of the Dielectric Constant and Volume Conductivity of Perchloro-p-xylene and Octachloro-p-xylene.

摘要

An experimental study was conducted to determine the dipole moment and the frequency and temperature dependence of the dielectric constant,and volume conductivity of perchloro-p-xylene and octachloro-p-xylene,two recently synthesized organic compounds. A sample holder,suitable for liquid and solid specimens,was designed which allows the environment of the sample to be controlled. Three terminal,guarded measurements were conducted on Solid samples of the compounds to determine the frequency and temperature dependence of the dielectric constant and the volume conductivity. The frequency and temperature ranges investigated were 100Hz to 5MHz and 70C to 100C,respectively. Polarization of the compounds was determined by measuring the variation of the dielectric constant and specific volume of solutions of the compounds and cyclohexane as a function of the weight fraction of the compound in solution. X-ray powder patterns were used to determine if anomalies in the temperature dependence of the volume conductivity were caused by structural changes in the crystal lattice. The dielectric constant of the compounds was determined to be frequency and temperature independent. The volume conductivity of the compounds was found to be dependent on frequency and temperature with anomalies noted at -20C to 0C for perchloro-p-xylene and at 30C to 60C for octachloro-p-xylene. (Author)