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Sodium bisulfite‐initiated polymerization of methyl methacrylate in aqueous medium in the presence of the metal oxides CuO and MnO 2
Author(s) -
Moustafa A. B.,
AbdElHakim A. A.
Publication year - 1977
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1977.070210403
Subject(s) - polymerization , sodium bisulfite , manganese , chemistry , oxide , inorganic chemistry , methyl methacrylate , metal , bisulfite , monomer , polymer chemistry , nuclear chemistry , organic chemistry , polymer , biochemistry , gene expression , dna methylation , gene
Sodium bisulfite‐initiated polymerization of methyl methacrylate (MMA) in water medium was carried out in the absence and in the presence of cupric oxide and manganese dioxide using various initiator concentrations at various temperatures ranging from 30° to 60°C. It seems that the metal oxide–water interface plays an important role, as it has been found that both oxides accelerate the rate of polymerization. Cupric oxide was found to be more effective than manganese dioxide. The cupric oxide was found to have nearly the same catalytic effect as the cuprous oxide, and manganese dioxide was found to be somewhat more effective than titanium dioxide. The initial rate of polymerization increased from 2.3 × 10 −5 mole/(l.sec) to 3.4 × 10 −4 mole/(l.sec) and to 6.6 × 10 −5 mole/(l.sec) when the metal oxide concentration increased from 0 to 3 g/l. in case of cupric oxide and manganese dioxide, respectively. The initial rate of polymerization increased from 3.7 × 10 −4 mole/(l.sec) to 4.2 × 10 −4 mole/(l.sec) and from 7.2 × 10 −5 to 2.2 × 10 −4 mole/(l.sec) when the temperature was raised from 30° to 60°C in the presence of cupric oxide and manganese dioxide, (9 g/l.), respectively. Both the rate of polymerization and the number‐average molecular weights were found to increase with increase the monomer concentration; the rate values were higher while the number‐average molecular weights were lower in case of cupric oxide than in case of manganese dioxide. For example, the rate of polymerization increased from 2 × 10 −5 mole/(l.sec) to 8.1 × 10 −5 mole/(l.sec) and from 1.9 × 10 −5 mole/(l.sec) to 6.9 × 10 −5 mole/(l.sec); and the number‐average molecular weight increased from 0.7 × 10 5 to 2.2 × 10 5 and from 1.5 × 10 5 to 4.9 × 10 5 in the presence of cupric oxide and manganese dioxide (10 g/l.), respectively, when the monomer concentration was increased from 23.5 g to 94 g/1. water. The apparent energy of activation for the polymerization of methyl methacrylate in water medium between 40° and 50°C was found to be 0.8 and 4.3 kcal/mole when using cupric oxide and manganese dioxide (9 g/l.), respectively.