TFE-based thermoprocessable copolymers having the following composition, expressed in percentage by moles on the total of the monomers: A) from 0.01 to 15% of the monomer of formula:
CF
2
═CFOCF
2
OCF
3
(a);
A1) tetrafluoroethylene from 99.99 to 85%; optionally B) one or more (per)fluorinated comonomers having at least one unsaturation of ethylene type, different from TFE; the sum of the molar percentages A)+B) being such as to give polymers showing at least one melting peak at the thermogravimetric analysis (DSC).