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-hydroxye thylmethacrylate (HEMA) with ethyleneglycoldimethacrylate (EGDMA). First, t he rate constant of decomposition, k(d), Of azobisisobutyronitrile (AIBN) u sed to initiate the copolymerization was investigated. Then, the reactivity ratios, r(1) and r(2), of the monomers (HEMA and EGDMA), and the terminati on rate constant, k(t), were determined. Rate constants were obtained by di fferential scanning calorimetry (DSC) experiments. The decomposition rate c onstant 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 35 3 K. The reactivity ratios, determined after analysis of the mixture compos ition by gas chromatography, exploitation of the data using the Meyer and L owry equation, and a numerical method, were found equal to r(1) = 0.811 and r(2) = 6.548. Also from the reaction rate obtained by DSC, the dependence of the termination rate constant with conversion and temperature has been e stablished. (C) 2001 John Wiley & Sons, Inc.