EFFECT OF RADIATION ON HIGH－CHARGE－DENSITY POLYDIALLY－DIMETHYL AMMONIUM CHLORIDE IN DILUTE AQUEOUS SOLUTION

The effect of radiation on high-charge-density cationic polymer, polydiallyl-dimethyl ammonium chloride (polyDADMAC), in dilute aqueous solution was investigated. The irradiated samples were characterized in terms of reduced viscosity and electric conductivity. The crosslinking reaction of polyDADMAC chains occurs preferentially in the irradiated samples at a concentration of polyDADMAC higher than 1.3 g/100 mL that was induced indirectly by the OH radicals, one of the radiolysis products of water. In more dilute samples (less than 0.8 g/100 mL) the chain scission of macro radicals appears to be the main reaction. N2O atmosphere enhances the erosslinking due to the extra OH radicals produced by reaction between N2O and eaq, another radiolysis products of water. Methanol and some mineral salts such as KC1, KBr inhibit the crosslinking to a certain extent. The mechanism of sensitization and inhibition is discussed in detail.