Polymerization of Methyl Methacrylate Using β-Picolinium p-Chlorophenacylide as Initiator

Abstract

Abstract The β-picolinium p-chlorophenacylide-initiated radical polymerization of methyl methacrylate was carried out at 60, 65, and 70°C by employing the dilatometric technique in a nitrogen atmosphere. A master graph of volume contraction vs percentage conversion was used to calculate the rate of polymerization (Rp), which is a direct function of the initiator concentration. The value of the exponent is 1.10 ± 0.10. The molecular weight of the polymer also increases with an increase in ylide concentration. The overall activation energy is calculated as 7.02 kcal/mol. The reaction involves bimolecular termination. Hydroquinone retards the reaction. Polar solvents do not affect Rp whereas the nonpolar solvent CC14 favors Rp but decreases the molecular weight of the polymer due to a chain transfer reaction. The value of the chain transfer constant (CS) is 6.67 × 10−4