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Effect of tetraalkylammonium salts on the tacticity of poly(methyl methacrylate), 2. . Initiation by potassium tert ‐butoxide
Author(s) -
Novakov Christo P.,
Tsvetanov Christo B.
Publication year - 1996
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.1996.030170305
Subject(s) - methyl methacrylate , tacticity , polymer chemistry , chemistry , tetrahydrofuran , monomer , polymerization , alkyl , anionic addition polymerization , toluene , potassium , ammonium , methacrylate , ammonium bromide , polymer , organic chemistry , solvent , pulmonary surfactant , biochemistry
The anionic polymerization of methyl methacrylate was carried out in the presence of potassium tert ‐butoxide ( t ‐BuOK)/quaternary ammonium salts (QAS) in toluene and tetrahydrofuran at −60°C. It was found that in toluene some QAS additives substantially increase the syndiotacticity of poly(methyl methacrylate). Two types of QAS were distinguished, quite different in their action. The addition of QAS with one or two longchain alkyl groups (>C 12 ), does not change significantly the mode of the monomer addition, whereas the polymerization in the presence of tetraalkylammonium salts with four equal substituents and dimethyldidodecylammonium bromide yields predominantly a syndiotactic polymer with high conversion and comparatively low polydispersity (M̄ w /M̄ w = 1.3−1.5). In some cases QAS additives are more effective modifiers than cryptand [2.2.2].