PROPAGATION AND SIZE-DEPENDENT CHAIN TERMINATION RATE PARAMETERS IN THE POLYMERIZATION OF ACRYLATES IN AQUEOUS-SOLUTION AS STUDIED BY PULSE-RADIOLYSIS

The radiation polymerizations of ethyl acrylate (EA) and hydroxyethyl acrylate (HEA) monomers in aqueous solutions were studied. For pulse r adiolytic experiments, optical detection was used to measure the conce ntration of intermediates. The absorption spectra taken after a 2.6-mu s pulse in N2O-saturated acidic solution of EA and HEA are shown to h ave maxima. at 300 nm. It was proved by comparative measurements that these maxima belong to alpha-carboxy alkyl radicals. At a low acrylate concentration (below 1 mmol . dm(-3)) and a relatively high dose/puls e value (above 30 yY), the decay of the transient signal occurs close to second-order kinetics. Average values of the termination rate param eters were calculated from aftereffect measurements. A computer progra m based on numerical integration was applied in order to estimate the individual rate parameters.