Radiation vulcanization of fluorinated copolymers

Irradiation of rubber-like fluorinated copolymers yields rubbers with poor mechanical properties, but in the presence of fillers it is possible to obtain rubbers with useful properties. The surface activity of the filler greatly influences the physical properties of the resulting rubbers. The best are irradiated rubbers containing active channel carbon; these are more stable to thermal ageing, action of solvents and static deformation than are the usual peroxide rubbers. Unlike PTFE and polytrifluorochlorethylene, rubberlike Kel-F type fluorinated copolymers become cross-linked when irradiated. The degree of cross-linking depends on their composition, on the radiation dose and on the medium in which the polymer is irradiated. The presence of oxygen favours a greater degree of cross-linking.