Radiation-induced emulsion copolymerization of tetrafluoroethylene with propylene. VI. Effects of pressure and temperature

In a radiation-induced emulsion copolymerization of tetrafluoroethylene with propylene, the effects of pressure and temperature were investigated in the range of 0 to 40 kg/cm2 and 7 to 530C at emulsifier concentrations of 0.5 and 2.0 percent. Both the polymerization rate and the molecular weight of copolymer increase with increasing pressure and decreasing temperature. These facts are mainly due to an increase of the monomer concentration in the polymer particles. The rate of polymer chain formation was found to be independent of pressure and temperature. The initiation reaction is due mainly to the entry of radicals generated in the aqueous phase into the polymer particles. The apparent activation energy is -2.0 to -3.8 kcal/mole for the polymerization in the presence of 0.5 percent emulsifier, but is nearly zero at an emulsifier concentration of 2.0 percent. This difference in apparent activation energies at emulsifier concentrations of 0.5 and 2.0 percent is explained in terms of the termination mechanisms