Iranian J. or Polymer Science and Technology Vol 4 No 1 (1995) Kinetics of Ce4+ /Sodium Sulphite Initiated Polymerisation of Acrylamide. A.K. Bajpai and S.K. Bajpai Department of Chemistry Government Autonomous Science College Jabalpur (M.P.), India Received : 16 November 1993; accepted 19 July 1994 ABSTRACT The kinetics of the aqueous polymerisation of acrylamide Initiated by the redox pair Ce•*/sodium sulphite is studied under atmospheric oxygen at 25+ 0.2 °C. The rate of polymerisation Is found to obey the equation: RP a [acrylamide]'^[Ge"] ' ° [sodium sulphite]'' The effect of temperature, neutral sales, complexing agents and organic solvents on the course of polymerisation is studied and numerical values of the Tudos parameter and retardation constants for retarders like organic solvents are evaluated . The energy of activation Is calculated to be 6.90 Kcal/mol from the Arrhenius plot. Key Words acrylamide, Ce (IV), sodium sulphite, polymerisation, retardation. INTRODUCTION Ce 4+ has long been recognised as a valuable reagent in analytical chemistry [1] . Besides its potential use as a versatile tool in analytical determinations, it has also been widely employed as an initiator in redox and graft polymerisation of a variety of vinyl monomers [2-4] . Although the efficiency of Ce 4+ in initiating redox polymerisation is well established in inert atmosphere [5-7], few studies have been made on Ce 4+ as an initiator in oxygen atmosphere. Here the results of kinetics of polymerisation of acrylamide initiated by Ce 4+ /sodium sulphite redox pair in atmospheric oxygen are reported. The monomer chosen for the polymerisation procedure was acrylam ' rlr• as its polymer has a wide spectrum of applications in the phenomenon of flocculation [8]. EXPERIMENTAL Preparation of Materials Acrylamide (Robert Johnson, India) was recrystallised twice from methanol (analytical reagent grade) and dried in vacuum over silica gel for a week . Ceric ammonium sulphate (Loba Chemie, India) was used without any further purification and its solution was prepared by the method described in the literature [9] . Sodium 10