Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9694149 | Thermochimica Acta | 2005 | 5 Pages |
Abstract
Excess molar enthalpies, HmE, of binary mixtures containing ethylene glycols and poly(glycols) + ethyl alcohol were measured by a flow microcalorimeter at 308.15 K and at atmospheric pressure over the whole composition range. Binary mixtures contain ethyl alcohol + ethylene glycol, + di(ethylene glycol), + tri(ethylene glycol), + tetra(ethylene glycol), + poly(ethylene glycol)-200, + poly(ethylene glycol)-300, + poly(ethylene glycol)-400, + poly(ethylene glycol)-600. Effects of the molecular weight distribution (MWD), of the polymer were investigated too, by preparing three additional samples of poly(ethylene glycol) with the same number average molecular weight (Mn â 300), but different MWD. For all mixtures, results were fitted to the Redlich-Kister polynomial. HmE curves are asymmetrical, showing positive values which vary from 280 J molâ1 (diethylene glycol + ethyl alcohol) to 1034 J molâ1 (mixture containing PEGs (200 + 400) + ethyl alcohol). Effects of changes in the glycols chain length and in MWD on the molecular interactions among the mixture components are discussed.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
Adriana Bigi, Fabio Comelli,