Heat capacities of perfluoropolyethers

✍ Scribed by Anna Staccione; Giuseppe Ajroldi; Giuseppe Marchionni; Luca Rebosio

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 204 KB
• Volume: 35
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19970930)35:13<2073::aid-polb8>3.0.co;2-x

✦ Synopsis

The heat capacities at constant pressure of liquid perfluoropolyethers with different chain structures were determined above the glass transition temperature up to 480 K by means of differential scanning calorimetry (DSC). The group contributions of the {O{, {CF 2 {, and {CF(CF 3 ){ were calculated as a function of the temperature. Anomalous behavior of ethereal oxygen in a perfluorinated chain, as previously found for group contributions to the glass transition and to the vaporization energy, was observed also for heat capacity where the oxygen contribution is consistently lower for perfluorinated polyoxides in comparison to the hydrogenated homologous. The jump in c p at the glass transition follows a regular behavior in the sense that DC p /beadmole is within the average range found by Wunderlich for the majority of polymers. Moreover, data obtained in the present work allow the prediction of c p of perfluoropolyethers of whatever structure between T g and 480 K.