ISSN:
0887-6266
Schlagwort(e):
thermoreverible gelation
;
cooperative interactions
;
PVC
;
liquid-liquid demixing
;
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The thermo reversible gelation of poly(vinylchloride) (PVC) is investigated by calorimetric and optical measurements. In a dynamic heating or cooling scan different thermal transitions are observed. The temperatures of these enthalpic transitions as well as the gel-sol temperatures are dependent upon the fraction of PVC present in the sample and on the solvent quality. After isothermal annealing, supplementary endotherms, formed at a slow rate, are found on heating. The temperature of these isothermally formed endotherms is nearly concentration independent. In a previous paper a model for the gelation of PVC was proposed, based on the formation of cooperative, intermolecular associations possible between subsequent, syndiotactic monomeric units. In this paper it is shown that this gelation mechanism is general and occurs in different solvents. © 1996 John Wiley & Sons, Inc.
Zusätzliches Material:
11 Ill.
Materialart:
Digitale Medien
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