Thermally Stable Fluoropolymers.
Abstract:
The preparation of thermally and chemically stable fluoropolymers was investigated. Three different fluoropolymeric systems were investigated in order to prepare elastomeric compositions. These were 1 the polyperfluorocyclobutanes, 2 the polyperfluorocyclobutyl perfluoroalkyl ethers, and 3 the polyperfluorocyclobutyl sulfides. Medium molecular weight polymers of the first system are friable solids. High molecular weight polymers of the second system vary from solids to liquids depending upon the ratio of cyclicaliphatic perfluorinated groups present. These may in the future offer promise of an elastomer having the required properties. Lack of solubility of the unsaturated systems presently precludes fluorination to improve stability. Tractable polymers of the third type have not yet been attained. Because of the high reactivity of the sulfide group, uncontrolled crosslinking has occurred during polymer formation. Lower temperature reactions appear to be leading in the direction which may circumvent the crosslinking problem. Author-PL