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Experimental determination of total pressure for the binary water and poly(ethylene glycol) mixtures

The total pressure of the systems containing water and three different poly(ethylene glycol)s with nominal molecular weights of 1000, 3000 and 6000 g mol-1 was measured isothermally at 303.15, 308.15, 313.15, 323.15, 333.15, 343.15, 353.15 and 363.15 K, using the improved static apparatus as described in [1] and ebulliometrically [2]. The data obtained cover the concentration range up to 50 weight % of the polymer. The 343.15 K isotherm was measured by both experimental methods, and both showed good continuity and performance. The vapour pressure data are expressed in terms of water activity, a1 = P1/P1o, where P1 is partial pressure and P1o is vapour pressure of pure water. The static and ebulliometric data agree well qualitatively, but quantitatively the static activities are higher about 0.25% in average, what is acceptable regarding the accuracy of measurements. The data were successfully correlated with the UNIQUAC-FV model described in [1]. Keywords: total pressure measurement ; polymer–solvent system ; vapour–liquid equilibria References [1] J. Pavlíček, G. Bogdanić, I. Wichterle, Fluid Phase Equilib. 454 (2017), 111–115. [2] J. Pavlíček, G. Bogdanić, I. Wichterle, Chem. Biochem. Eng. Q. 28 (2014) 447–450. Acknowledgment This study was partly supported by the Czech Science Foundation (Grant Nos. 15-19542S and 17-05421S).

: total pressure measurement ; polymer–solvent system ; vapour–liquid equilibria

I. Wichterle (Chairperson of Scientific Committee) G. Bogdanić (Scientific Committee)