Tetraalkylammonium and Other Bulky Counterions for Anionic Polymerization

Tetraalkylammonium and Other Bulky Counterions for Anionic Polymerization 

Haggard and Lewis have shown that tetrabutylammonium alkoxides polymerize methacrylates in alcohol solution [68]. Block polymer synthesis is not possible since the ester groups on the monomer exchange with the solvent. 

Hogen-Esch [72] used a tetraphenylphosphonium gegenion for anionic polymerization of MMA. Low temperatures (-80 °C) were used 

Anionic polymerization of (meth)acrylates with hindered ester functions can most likely be conducted at room temperature and above to remove the heat of polymerization with low boiling solvents. Polymerization of the important methyl and ethyl (meth)acrylate members of the family, however, are still plagued by chain termination at higher temperatures. The phosphorus based counterions have a stability advantage over tetraalkylammonium counterions which undergo Hoffman elimination. 

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