Graft copolymerization of tertra-fluoro-ethylene onto semi-vulcanized butadiene acrylonitrile rubber was carried out by pre-irradiation with

60

Co γ rays. The monomer of tertrafluoro-ethylene was obtained through degradation of its polymer. Typical results of the copolymerization was tabulated.

The mechanical properties of butadine acrylonitrile after copolymerization copolymer changed insignificantly. The coefficient of friction of rubber

however

decreased conside-rally with increase of graft percentage.