| Abstract: | The phase behaviour of perfluorocarbons in various solvents has been investigated. In case of perfluorohexadecane the state diagrams with trichlorotrifluoroethylene (CF2Cl-CFCl2) known also as Freon F113 and hexafluorobenzene (C6F6) as solvents could be determined in the total concentration range and also at temperatures far below the melting temperatures of the pure components. Beside the normal melt transitions in this binary systems some not yet known intramolecular phase transitions were found. From the course of the liquidus curve the Flory-Huggins interaction parameter of these systems could be determined. So statements about the quality of these solvents can be made. The investigated substances are suitable solvents for all perfluorocarbons which are actually available. The high molecular polytetrafluoroethylene (PTFE) cannot entirely be dissolved by these solvents, although traces are soluble. The reason is that the boiling points and critical temperatures of the solvents lie below the temperatures of the liquidus curve of the polymer of the considered system. |
