Perfluoropolyethers having brominated end groups and fluoroelastomers obtained therefrom

摘要

New perfluoropolyethers comprising repeating units chosen from among <IMAGE> statistically distributed along the chain, having a controlled molecular weight and brominated end groups, prepared starting from the product of the photochemical oxidation of C2F4, and/or C3F6, containing peroxidic oxygen, and subsequent treatment in liquid phase with bromine, at temperatures ranging from -40 DEG to 130 DEG C. in the presence of ultraviolet radiations, said new perfluoropolyethers derivatives being useful as additives in rubber mixes vulcanizable with peroxides, in amounts of 0.01 to 5 parts by w per 100 parts by weight of elastomer, optionally in combination with non brominated perfluoropolyethers, to improve the processability in the extrusion and the detachability of the vulcanized articles from the molding.