Low-temperature graft polymerization of tetrafluoroethylene in crystalline polydimethylsiloxane matrix

It is shown that during slow cooling of tetrafluoroethylene (TFE) solutions in dimethylsiloxane rubber the rubber is crystallized. The significant part of TFE (20-30% of the rubber wheight) is sorbed in pores of cyrstalline matrix and does not form the proper crystalline phase. In the course of heating of such samples irradiated at 77 K by γ-rays (60Co) the grafting of TFE takes place in the wide range of temperatures up to the melting point of the rubber. The graft copolymer with low content of graft chains of PTFE is soluble in benzene. In IR-spectra of films obtained from such solution the absorption bands at 1140-1170 and 1245-1255 cm-1 are observed being characteristic for PTFE. The melting heat of rubber crystallites decreases with increase of the amount of graft PTFE. The preliminary introduction of TFE in crystalline rubber pores permits to accomplish the effective grafting of this monomer