Radiation-induced emulsion copolymerization of tetrafluoroethylene with propylene. V. Formation of acid and its effect

Abstract

In the radiation-induced emulsion copolymerization of tetrafluoroethylene with propylene, it was found that hydrofluoric acid (HF) is formed in the course of polymerization. The amount of HF formed increased linearly with the irradiation time in all cases. The rate of HF formation was maximum at 0.3 wt-% emulsifier and increased linearly with tetrafluoroethylene content in the monomer mixture. On the other hand, the conversion and the molecular weight decreased remarkably by addition of 0.1M HF. The particle diameter of copolymer obtained in the presence of HF was larger than that obtained in the HF-free system. On the contrary, the number of polymer particles was less than that obtained in the HF-free system. The decrease in the conversion and the molecular weight was attributed mainly to the conversion of part of ammonium perfluorooctanoate to perfluorooctanoic acid by formation of acid or addition of acid.