ISSN:
0887-6266
Keywords:
heat capacity
;
calorimetry
;
perfluoropolyethers
;
group contributions
;
Δcp at Tg
;
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
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—,—CF2—, and —CF(CF3)— 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 cp at the glass transition follows a regular behavior in the sense that ΔCp/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 cp of perfluoropolyethers of whatever structure between Tg and 480 K. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2073-2082, 1997
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
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