| abstract |
A process to obtain perfluoropolyethers comprising:n a) synthesis of the peroxidic perfluoropolyether by one ofnthe following reactions:n a1) TFE photooxidation, in the presence of UV light, at lowntemperature, in solvents selected between perfluoro-carbonsnand (mono)hydrofluorocarbons, of general formula:n C y F (2y+2-x) H x nwherein y is an integer from 2 to 4; x is an integernequal to 0 or 1; in the presence of fluorine diluted withnan inert gas; or a2) TFE oxidation using as radical initiator fluorine ornhypofluorites of formula R f OF (III) n(R f pefluoroalkyl radical from 1 to 3 carbon atoms),noperating from -40°C to -100°C at a pressure comprisednbetween 0 and 12 bar, in an inert solvent under thenreaction conditions; b) thermal treatment of the product obtained in a) at antemperature from 150°C to 250°C, optionally in thenpresence of a regulating agent of the molecular weightnselected between fluorine or hypofluorite of formulan(III); c) treatment with elemental fluorine of the polymer obtainednin step b) at temperatures from 100°C to 250°C, or byntreatment with fluorine in the presence of UV radiations,noperating at temperatures from -50°C to 120°C. |