Thermodynamics of aqueous solutions of poly ethylene glycol di-methyl ethers in the presence or absence of ammonium phosphate salts

摘要

Precise measurements of density and sound velocity at different temperatures ranging from 283.15 to 308.15K for solutions of PEGDME250, PEGDME500 and PEGDME2000 in water and of PEGDME500 in aqueous solutions of 0.500molkg-1 ammonium di-hydrogen phosphate ((NH4)H2PO4) and di-ammonium hydrogen phosphate ((NH4)2HPO4), binodal curves at temperature ranges 293.15-318.15K for the aqueous PEGDME500+(NH4)2HPO4, PEGDME500+(NH4)3PO4, PEGDME2000+(NH4)H2PO4, PEGDME2000+(NH4)2HPO4, PEGDME2000+(NH4)3PO4 and PPG400+(NH4)2HPO4 two-phase systems, and liquid-liquid equilibrium data at temperature ranges 298.15-318.15K for the aqueous PEGDME500+(NH4)2HPO4 and PEGDME2000+(NH4)2HPO4 two-phase systems have been taken. From the experimental density and sound velocity data, the apparent specific volume, excess specific volume, isentropic compressibility and isentropic compressibility deviation values have been determined and the effect of temperature, charge on the anion of electrolytes and molar mass of PEGDME on the volumetric and compressibility properties of the investigated polymer solutions as well as on the salting-out effect of PEGDMEs produced by ammonium phosphate salts has been studied.