Time resolved study of the high energy radiation initiated polymerization

Abstract

The EB (electron beam) initiated polymerization of ethyl acrylate (EA) and ethyl methacrylate (EMA) in dilute cyclohexane solution was studied by pulse radiolysis technique with transient spectroscopic detection. The maximum in the absorption spectrum of the intermediates lies at λ = 290–320 nm in EA solution and at λ = 285 in EMA solution. The extinction coefficients of the intermediates at the maximum of the spectrum were calculated to be ε 285nm ∼ 700 mol −1 dm 3 cm −1 in EMA solution and ε 290–320nm ∼ 300 mol −1 dm 3 cm −1 in EA solution. From the decay curves rate parameters of termination (2 k t) were calculated. The decays were generally found to be second order with a rate coefficient of 1.4 × 10 9mol −1 dm 3 s −1 in EMA solutions and 6 × 10 8mol −1 dm 3 s −1 in EA solutions. In some cases deviation from a single second order was observed. This was interpreted in terms of the hindered mobility of the growing radicals.