Linear perfluoropolyethers having an improved thermooxidative stability

摘要

Linear perfluoropolyethers of formula: T-O (CF2O)n(CF2CF2O)m(CF2CF2CF2O)r(CF2CF2CF2CF2O)s-T1 wherein n, m, r, s are integers such that the polymer number average molecular weight is comprised between 700 and 100,000 and the n/(n+m+r+s) ratio ranges from 0.05 to 0.40, and respective preparation process by addition of a peroxidic perfluoropolyether of formula (III): T4-O(CF2O)n'(CF2CF2O)m'(O)h-T5 having a PO from 1.8 to 4, to a perfluoropolyether oil preheated at a temperature comprised between 150 DEG C and 250 DEG C and subsequent exhaustive fluorination of the obtained compound.