Study of the isothermal bulk polymerization of vinyl acetate by differential scanning calorimetry

The course and kinetics of the isothermal bulk polymerization of vinyl acetate were studied by differential scanning calorimetry. The initiator used was 2,2′‐azoisobutyronitrile. The polymerization was investigated at temperatures between 55 and 70°C at constant initiator concentration, 5,0.10−2 mol/l. The heat of polymerization at 60°C is – 19,5 kcal/mol and decreases with increasing temperature. Initial rate constants for the polymerization were also determined and from them the overall activation energy, 21,6 kcal/mol. Another series of polymerization experiments were performed at 60°C with variable amounts of the initiator. The overall rate of polymerization at low degrees of conversion depends on the square root of the initiator concentration which is in agreement with the assumed kinetic scheme.