Any elastomeric high polymer containing fluorine; they may be homopolymers or copolymers. Fluorocarbon polymers include a large group of fluoroelastomers, including a copolymer in which the molecular skeleton is a P═N chain containing approximately equal numbers of tri- and heptafluoroethoxy side groups. Such polymers are amorphous, thermally stable, noncombustible. Generally resistant to attack by solvents and chemicals, have low glass transition temperature (−77C), and are generally resistant to attack by solvents and chemicals.