engleski

Apparatus for quick determination of liquid–liquid equilibrium in polymer solutions by the turbidimetric method (silver medal)

A set-up for semiautomatic and quick measurement of liquid–liquid equilibrium in polymer solutions by the cloud point method was assembled and checked. The whole arrangement is shown in Figure 1. It consists of equilibrium cell, programmable thermostat, laser source with a photodiode sensor, and computer with LabVIEW software. The cell is shown in details in Figure 2. Figure 1. Assembly of apparatus Figure 2. Equilibrium cell Only 5 ml of liquid mixture is sufficient for measurement of one experimental point on the coexistence curve, which procedure takes one hour, approximately. The programmable thermostat has been used for temperature control, the turbidity has been detected by measuring intensity of a laser beam scattered by the mixture. A photodiode sensor was used to measure the scattered light intensity. Final phase split temperature as measured with a Pt100 resistance thermometer has been recorded and evaluated using the LabVIEW software. The coexistence curve of the polystyrene + methylcyclohexane system was measured in the region of the upper critical solution temperature (UCST). The obtained results are in a good agreement with available literature data.

determination of LLE; polymer solutions; turbidimetric method

silver medal for innovation