Radical polymerisation of ethyl acrylate in the presence of molecular oxygen

Abstract

Oxygen as a promoter of radical polymerisation of ethyl acrylate was studied in the aqueous medium. Cu²⁺ was chosen as the catalyst for the ascorbic acid (AA) -0₂ redox reaction, constituting a three component initiating system. The rate of polymerisation, R_p, was observed to increase, remain constant and then decrease with increasing [Cu²⁺]. R_p increased with [O₂] upto ~6.5×10⁻⁴M and thereafter remained constant. [AA]>1.2×10⁻³M did not influence the rate. R_p always increased with monomer [M] at fixed [Cu²⁺], [O₂] and [AA]. However, the order with respect to [M] increased with increasing [Cu²⁺]. The rate of polymerisation increased with ionic strength, μ and decreased with [H₂SO₄]. There was an initial increase in R_p followed by a decrease with increasing temperature. Conditions were identified where R_p depended only on [Cu²⁺] and [M] or [M] only for industrial exploitation. Kinetic chain length of the polymers obtained under various experimental conditions were determined viscometrically.