SU241099A1 - METHOD FOR DETERMINING THE MOMENT OF A MUTUALLY TRANSITION OF A TOKONCONDUCTING COLLOID SOLUTIONS A TRUE - Google Patents

Description

The invention relates to the field of colloidal chemotherapy, in particular, to methods for determining the moment of transition of a non-conducting colloidal solution to a true one and vice versa.

Methods are known for determining the moment of transition of a non-conductive colloidal solution to a true one by registering a curve, the variable parameter of which is temperature. At the same time, the optical density of the solution in the infrared region of the spectrum is used as another parameter of the curve, depending on the temperature change. However, the known methods do not provide the necessary accuracy, the lack of transparency of the solution makes it difficult to establish the moment of transition.

A distinctive feature of the proposed method for determining the moment of mutual transition of a current-conducting colloidal solution to a true one is that either the solution’s dielectric constant or its dielectric loss tangent are used as another parameter depending on the temperature measurement. court r about the moment of transition. This method allows you to more accurately determine the moment of transition.

howl of acids. Dielectric measurements were carried out in a coaxial-cylinder capacitor. In the case, having in the lower part a channel with a diameter of 13 mm and being an external electrode, an internal cylinder - an electrode - is mounted. Electrodes are insulated from each other by a teflon sleeve. The radial gap formed by the two electrodes is 0.25 mm. The height of the working gap 50mm.

The condenser was filled with the test solution using a filling pen mounted in the B-part and a part of the body. After filling, the condenser was placed in a thermostat, which is a vessel filled with silicone fluid, through the jacket of which that liquid circulates from the ultrathermostat.

To determine the dielectric constant E and the dielectric loss tangent tg6, an installation consisting of a TM-351 bridge (Tesla), a TM-512 stabilized frequency generator and a TM-622 zero indicator is used.

The TM-351 bridge is designed to measure capacitance (dielectric constant) and dielectric loss tangent in the audio frequency range of 25-10000 Hz. This device uses a bridge measurement method. The bridge circuit is designed as a Schering bridge with a direct reading of the capacitance in

the entire range of operating frequencies and loss tangent at a frequency of 1 kHz. Measurements are made by the direct method. The capacitance and the loss tangent are counted directly on the instrument. The capacity scale is calibrated in values from 100 to 1100 pf. The measurement error of the capacitance does not exceed rf; 0, l pf. The measurement range of the loss tangent is -0.1 to + 56i / o. The measurement error tg6 does not exceed ± 0,05o / o.

For the litany of the bridge, an acoustic generator TM-512 with a frequency range of 25-10000 Hz and a distortion factor of 2o / o is used for sound frequency. A zero indicator of the TM-622 type is used as a bridge balancing indicator.

Work on the installation is carried out in the following manner.

After installation and grounding devices are connected to the network through the stabilizer. Pa generator set the operating frequency. The same frequency is set by means of the selectivity and phase shift switches on the zero indicator. After the generator is turned on and a 5-minute warm-up period, the operating voltage of 15 e is established on the voltmeter. Then the zero indicator is turned on. The capacitance capacitance is connected to the terminals C with the bridge being balanced by means of pens "capacitance in picofarads and tg6 in percent and counting Saam and tgeasM values. The capacitance value is taken directly, and to obtain the tg6 value at frequencies other than 1 kHz, the counted value multiplied by the corresponding frequency in kilohertz. The dielectric constant e is calculated as the ratio of the capacitance of a capacitor filled with the test solution to the capacitance of an empty capacitor. In order to eliminate the effect of the capacitance supply w, their contacts, it is necessary to measure the capacitance of the same capacitor filled with a calibration liquid with a known dielectric constant. L1 tetaxylol is used as a calibration liquid.

The calculation of the dielectric constant is made according to the formula

With jf - with to

. (zst-1)

+ 1,

SG-K

where is the dielectric constant of the test solution;

b "- dielectric constant of the calibration fluid; CK-capacitance of an empty capacitor;

Cjf-capacitor filled

test solution; CCT - capacitor capacity filled

calibration fluid.

All containers included in this formula can be expressed in any units, for example, in the units of the scale of the capacitor. The error ... when measuring it exceeds 1.

Temperature measurements of e and tg6 are carried out in the temperature range of 20-180 ° C, and the system is maintained for 15-20 minutes at each measured temperature. The temperature is maintained with an accuracy of 0.1 ° C. With a change in temperature at the transition point, the curves e (/) and tg6 () show sharply pronounced sharp maxima that coincide in temperature for в and tg6, with increasing soap concentration in the studied systems, the e and tg6 maxima increase in absolute value and shift towards higher temperatures.

Subject invention

The method of determining the moment of mutual transition of a non-conductive colloidal solution into a true one by registering a curve, the variable parameter of which is a temperature, characterized in that

increasing the accuracy of determination, as another parameter of the curve, depending on the temperature change, use the dielectric parameters of the solution — dielectric constant or dielectric loss tangent and judging the transition moment by the extremum of the curve.