Ethylene-chlorotrifluoroethylene copolymer (ECTFE) has a linear macromolecule in which the predominant alternating copolymer is [—(CH2 )2 —CF2 —CFCl—]n. This copolymer exhibits useful properties for a wide range of temperatures, that is, from cryogenic temperatures up to 180°C. Its permittivity is low but stable over a broad temperature and frequency range.
