Perfluoropolyethers and processes therefor and therewith

摘要

A perfluoropolyether, a composition comprising the perfluoropolyether, a process for producing the perfluoropolyether, and a process for improving the thermostability of grease or lubricant are provided. The perfluoropolyether comprises (1) perfluoroalkyl radical end groups in which the radical has at least 3 carbon atoms per radical and is substantially free of perfluoromethyl and perfluoroethyl end groups or (2) at least one bromine or iodine atom at the primary position of the perfluoropolyether.