RADIATION-INDUCED EMULSION POLYMERIZATION OF ETHYLENE .4. EFFECT OF PRESSURE, TEMPERATURE, AND ADDITIVES ON RATE IN CONNECTION WITH NUMBER OF POLYMER PARTICLES

The effects of pressure, temperature, and additives on the rate of radiation-induced emulsion polymerization of ethylene with FC-143 as emulsifier were studied kinetically. The rate of polymerization was proportional to the 2. 5 power of ethylene fugacity, and the apparent rate constant was constant below 78 C. Above this temperature, the rate constant decreased with an apparent activation energy of minus 8. 2 kcal/mole. These facts can be interpreted in connection with the polymer structure and the change of rate of escape of radicals from the polymer particle into the aqueous phase. The rate of polymerization decreased on addition of a series of n-aliphatic alcohols due to the chain-transfer reaction and consequent escape of radicals to the aqueous phase. Addition of electrolytes increased the rate of polymerization as a result of the increase of the number of polymer particles.