Radiation‐induced polymerization of styrene in the presence of n‐dibutyl disulfide

Abstract

AbstractThe γ‐radiation‐induced polymerization of pure styrene and styrene‐n‐dibutyl disulfide mixtures has been studied at a number of temperatures and dose rates. Up to 0.04 Mrad/hr the rates were proportional to the square root of the dose rate. By measuring the rates at a number of disulfide concentrations and at three different dose rates, the relative rates of radical formation were determined by kinetic analysis. Considerable energy transfer from the styrene to the disulfide was found. The relative contributions of energy transfer and radical formation were separated by using the kinetic scheme of Nikitina and Bagdasaryan. Values of 8.5 and 3.1 were found for the relative rates of radical production and energy transfer, respectively. This leads to a G (radical) value of 3.1 for n‐dibutyl disulfide. With azobisisobutyronitrile as the initiator, the chain transfer constant to the disulfide was determined at 55°C. Finally, the sulfur content of a number of the polymers were determined, an average of two sulfur atoms per polymer chain was found. In general, the rate of polymerization was found to increase in the presence of dibutyl disulfide.