| abstract |
POLYMERISATION OF TETRAFLUOROETHYLENE TO SOLID POLYMERS HAVING MELTING POINTS ABOVE 300*C., AND DIFFERING FROM KNOWN POLYTETRAFLUOROETHYLENE IN THEIR BEHAVIOUR AT TEMPERATURES OF THIS ORDER, BY MEANS OF A CATALYST SYSTEM COMPRISING ANTIOMONY PENTAFLUORIDE AND A NON-AQUEOUS SOLVENT AT MODERATE TEMPERATURES AND PRESSURES, PARTICULARLY 0*-50*C. AND AUTOGENOUS PRESSURES. EXAMPLES OF SOLVENTS ARE LIQUID SULPHUR DIOXIDE, TRIFLUOROACETIC ACID, FLUOROSULPHONIC ACID AND TETRAFLUOROETHYLENE TETRAMER. THE SOLVENT APPEARS TO HAVE SOME INFLUENCE ON THE PROPERTIES OF THE POLYMER. REACTION TIMES ARE IN THE REGION OF 30 MINUTES TO TWO HOURS AND INORGANIC CATALYST RESIDUES ARE WASHED OUT OF THE POLYMERS AND THE LATTER CONVENIENTLY PURIFIED BY HEATING WITH NITRIC ACID. |