Kinetic Analysis of the 60Co γ Ray-Initiated Inverse Emulsion Polymerization of Sodium Acrylate Solutions

The kinetics of the 60 Co γ ray-initiated inverse emulsion polymerization of aqueous sodium acrylate solutions in kerosene with Span 80 as the emulsifier was investigated. The conversion-time curves were analyzed using the equation [ex/(1 - e) - In(1 - x)] = B (constant) + [nk p /(V p ∞N A )]t, derived on the basis of a monomer droplet nucleation mechanism. The following expressions were obtained for K = [nk p /(V p ∞N A )] under the experimental conditions investigated : K ∞ [dose rate] 0.9 [sodium acrylate] 0.5 [Span 80] 0.4 , which was simplified to n ∞ [dose rate] 0.9 , nk p ∞ [sodium acrylate] 0.5 , and n/V p ∞ ∞ [Span 80] 0.4 . The polymerization rate during the steady state (approximate conversion range 20-80%) could be expressed by R p = KxC 0 ∞ [dose rate] 0.9 [sodium acrylate] 1.5 [Span 80] 0.4 . The kinetic analysis suggests a dose rate independent polymerization process for the system studied such that, at any time, there was only one active passage of radiation through a droplet, viz., all polymer radicals resulting from a radiation passage were terminated before another passage.