Teflon is polytetrafluoro ethylene and it is prepared from tatrafluoro ethylene by heating under pressure in the presence of ammonium peroxydisulphate.
$n CF _{2}= CF _{2} \frac{\left( NH _{4}\right)_{2} S _{2} O _{8}}{\text { high pressure }}\left( CF _{2}- CF _{2}\right)_{n}$
It is chemically inert and heat resistant polymer: