| Abstract: | The effect of reaction conditions on the rate of radiation-induced emulsion polymerization of ethylene was studied by use of a 500-ml autoclave. Among various kinds of emulsifiers, a series of potassium salts of fatty acids gave high rates of the polymerization. The polymerization was inhibited by the presence of oxygen, but the rate of polymerization followed by the induction period was not influenced by the initial presence of oxygen. Stirring rate and the monomer: water ratio did not affect the rate of polymerization. The rate of polymerization was maximum at about 80°C, and number-average molecular weight was influenced by the temperature in a similar manner as the rate of polymerization. This suggests that the change of mobility of propagating radical in the polymer particle changes the rate of termination reaction. The rate of polymerization was proportional to the 1.7 power of the reaction pressure. |
