CH2CX2n

CH2CX2n refers to a class of polymers derived from monomers with the general formula CH2=CX2, where X represents a halogen atom. These polymers are characterized by a repeating unit where a carbon atom is double-bonded to two halogen atoms, and this unit is linked together by single bonds in a long chain. The simplest example is polytetrafluoroethylene (PTFE), commonly known by the brand name Teflon, where X is fluorine (F). In this case, the monomer is tetrafluoroethylene (C2F4), and the polymer repeat unit is -[CF2-CF2]-. Other common examples include polyvinylidene fluoride (PVDF), where X is fluorine (F) and hydrogen (H) in an alternating pattern, and polychlorotrifluoroethylene (PCTFE), where X is fluorine (F) and chlorine (Cl).

These polymers exhibit a range of unique properties due to the presence of halogen atoms, particularly fluorine. They are often characterized by high thermal stability, excellent chemical resistance, low friction coefficients, and good electrical insulating properties. The specific properties depend on the type and number of halogen atoms present. For instance, PTFE is known for its extreme non-stick properties and resistance to almost all chemicals. PVDF is known for its piezoelectric and pyroelectric properties, making it useful in sensors and actuators. PCTFE offers a good balance of properties, including excellent barrier properties against gases and moisture. These polymers find widespread applications in various industries, including aerospace, automotive, electronics, chemical processing, and cookware.