Polymerization of methyl methacrylate in water in presence of the metal oxides TiO2 and Cu2O

Abstract

AbstractRates of sodium bisulfite‐initiated polymerization of methyl methacrylate in water were determined in absence and in presence of the metal oxides TiO2 and Cu2O at 30°, 40°, 50°, and 60°C. Cuprous oxide and titanium dioxide enhanced the rate of polymerization and reduced the molecular weight as compared with the figures obtained in absence of oxide, the effect of the former being more pronounced than the latter. With TiO2, the rate was increased from 2.3 to 3.2 × 10−5, while with Cu2O, it was increased to 8.6 × 10−5 mole/l./sec, both at concentrations of 9 g/l. water. The apparent energy of activation for the polymerization of methyl methacrylate between 40°C and 50°C was found to be 15.6 kcal/mole in absence of the metal oxides, and 7.6 kcal/mole and 2.8 kcal/mole in presence of titanium dioxide and cuprous oxide, respectively. The number‐average molecular weight was found to decrease slightly with the addition of TiO2 but to decrease greatly when Cu2O was added.