par De Brouckère, Lucia 
;Van Nechel, Roger
Référence Bulletin des Sociétés chimiques belges, 61, 5-6, page (261-292)
Publication Publié, 1952
;Van Nechel, Roger Référence Bulletin des Sociétés chimiques belges, 61, 5-6, page (261-292)
Publication Publié, 1952
Article révisé par les pairs
| Résumé : | Dielectric contants and loss factors have been determined for solutions of polyvinyl chloride in tetrahydrofurane. The molecular weight of the polymer was 110.000. The concentrations used ranged from 1 to 8 grs per hundred milliliters, the frequencies from 0,5 to 35 megacycles, the temperatures from‐35°C to‐10°C. A Twin T impedance bridge and a specially designed cell were used throughout the work. The critical frequencies and relaxation times were determined. The dispersion curves were analysed according to the method of Fuoss and Kirkwood and the factor α, caracteristic of the dispersion of relaxation times about their mean value, was evaluated at.7. The dipole moment of the molecule was found to be about 50 D. The energies and entropy of activation for the dipole rotation were calculated from the variation of critical frequency with temperature. The following values were obtained: ΔH*=2,1 K. Cal. ΔG*=5.0 K. Cal. ΔS*=‐0.01 K. Cal. Particular stress is laid on the α small value of the entropy of activation. Copyright © 1952 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim |
