Radiation‐induced copolymerization of tetrafluoroethylene and 3,3,4,4,5,5,5‐heptafluoropentene‐1 under pressure

Abstract

AbstractAn investigation was made of the γ‐ray‐induced copolymerization of tetrafluoroethylene and 3,3,4,4,5,5,5‐heptafluoropentene‐1. At 22°C at 5000 and 10 000 atm the polymerization rate changes little between 0 and 75 mole‐% tetrafluoroethylene. Above 90 mole‐% the rate increases greatly. Molecular weights vary with composition in a fashion similar to the variation of the rates. Crystallization occurs in the bulk pentene at 13 500 atm at 24°C. The polymerization rate is very low in the solid state. Under some conditions polymerization continues long after irradiation is ended. Both reactivity ratios favor the pentene. Several copolymer properties were studied. The polymers are amorphous and soluble in perfluoro ethers, perfluoro alkanes, and perfluoroaromatics if they contain less than 80% tetrafluoroethylene. The glass temperatures of the amorphous polymers decrease and the thermal and radiation stability increases as the tetrafluoroethylene content increases.