Determination of exchange enthalpy and entropy parameters of the equation-of-state theory for poly(dimethyl siloxane) and some aromatic solvents by inverse gas chromatography
✍ Scribed by Cankurtaran, �zlem; Yilmaz, Ferdane
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 85 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0959-8103
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✦ Synopsis
The speci®c retention volumes, V g o of toluene, ethyl benzene, n-propyl benzene and isopropyl benzene on poly(dimethyl siloxane)(PDMS) were measured at temperatures between 333 and 403 K by inverse gas chromatography. The parameters of hard-core interaction, x t ? , effective exchange energy, X 12 , exchange enthalpy, X 12 , and exchange entropy, Q 12 in the equation-of-state theory were determined. The parameters x t ? of the isopropyl benzene-PDMS pair decreased from 0.65 to 0.60 while those of others decreased from around 0.77 to 0.69 with increasing temperature. The values of the parameters X 12 also decreased as molecular weight of the substituted aliphatic group on the benzene ring of the solvent increased, ie 15 J cm À3 in toluene and 5 J cm À3 in isopropyl benzene. Both X 12 and Q 12 show negligible dependence on temperature.