Kinetic study by differential scanning calorimetry of the bulk copolymerization of 2-hydroxyethylmethacrylate with ethyleneglycoldimethacrylate

This article presents a kinetic study of the copolymerization of 2‐hydroxyethylmethacrylate (HEMA) with ethyleneglycoldimethacrylate (EGDMA). First, the rate constant of decomposition, kd, of azobisisobutyronitrile (AIBN) used to initiate the copolymerization was investigated. Then, the reactivity ratios, r1 and r2, of the monomers (HEMA and EGDMA), and the termination rate constant, kt, were determined. Rate constants were obtained by differential scanning calorimetry (DSC) experiments. The decomposition rate constant of AIBN follows an Arrhenius law in the temperature range 320–400 K. Copolymerizations were carried out in the pans of the DSC apparatus at 353 K. The reactivity ratios, determined after analysis of the mixture composition by gas chromatography, exploitation of the data using the Meyer and Lowry equation, and a numerical method, were found equal to r1 = 0.811 and r2 = 6.548. Also from the reaction rate obtained by DSC, the dependence of the termination rate constant with conversion and temperature has been established. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1220–1228, 2001