Solubility of alcohols in ethylene-vinyl alcohol copolymers by inverse gas chromatography

✍ Scribed by Rafael Gavara; Ramón Catalá; Susana Aucejo; Daniel Cabedo; Ruben Hernandez

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 683 KB
• Volume: 34
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(199608)34:11<1907::aid-polb8>3.0.co;2-o

✦ Synopsis

SYNOPSIS

Sorption isotherms of alcohols in EVOH copolymers were determined by inverse gas chromatography below and above the glass transition temperature. The sorbates studied were: methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, and t-butanol.

From the sorption isotherms, Henry's law solubility coefficients ( S ) were evaluated and correlated to size, condensability, and -OH position in the molecule as well as on temperature. Molecular dimension was an important factor, affecting the solubility via two contrary effects: molecular size and condensability. When comparing alcohols of the same size, primary alcohols were sorbed more than secondary alcohols and these more than tertiary alcohols a t every temperature in the study. At low temperatures, the larger the size the greater the solubility, contrary to what was observed at high temperatures. Temperature effect on solubility was also tested applying Van't Hoffs equation. Since S behaved differently below and above Tg for every sorbate two values of the enthalpy of solution were obtained, positive above Tc and negative below T,.