Influence of alternating sequential fraction on the melting and glass transition temperatures of ethylene–tetrafluoroethylene copolymer

The melting (Tm) and glass transition (Tg) temperatures of a series of ethylene (E)–tetrafluoroethylene (TFE) copolymer (ETFE) have been found to show unique dependence on the TFE content with the minimal and maximal points. These behaviors have been interpreted successfully on the basis of the degree of alternation of E and TFE monomeric units along the skeletal chain. The melting point of a perfectly alternating copolymer is estimated to be 295 °C on the basis of the dependence of Tm using a modified Flory’s equation. The corresponding Tg was estimated as 145 °C by applying a modified Gibbs–Damnation’s equation.