Stereospecific polymerization of alpha-substituted acrylic acid esters polymerization

Stereospecific Free-Radical Polymerization of Methacrylates Using Fluoroalcohols as Solvents

“…The additional bulkiness of EMA compared with MMA might prevent an effective hydrogen-bonding interaction with the bulky PFTB under certain conditions. The polymerization of EMA in HFTB at −40 °C resulted in a syndiotactic specificity of 86.9% (run 32 in Table ), which is the highest for the radical polymerization of methacrylates to the best of our knowledge. , …”

“…The other fluoroalcohols also were effective in enhancing the rr specificity during the polymerization at −40 °C, although their effects were not so obvious at 20 °C and 60 °C. The rr specificity observed in run 17 in Table (82.9%) is considered to be the highest for the radical polymerization of MMA. , Figure shows the 1 H NMR spectrum of the PMMA obtained in run 17. The high syndiotacticity of the polymer is evidenced by the spectral pattern due to the α-methyl and β-methylene…”

“…However, many industrially important vinyl polymers including poly(methyl methacrylate) (PMMA) and polystyrene are produced by radical polymerization, which is more versatile and economical compared with other types of polymerizations, but is generally poor in stereocontrol. Hence, the development of stereoregulation methods for radical polymerization can contribute to the industrial production of polymers with improved properties. − …”

Stable Carbanions by Quantitative Metalation of Cationically Obtained Diphenylvinyl and Diphenylmethoxy Compounds: New Initiators for Living Anionic Polymerizations

“…In the anionic polymerization of polar monomers, e.g., methacrylates or vinylpyridines, the size of the counterion is of great importance for controlling the tacticity and the molecular weight distribution (MWD) of the obtained polymers. , For instance for the living anionic polymerization of N , N -dimethylacrylamide only Cs + leads to narrow MWD . In addition, initiators with reduced nucleophilicity (e.g., diphenylalkyl anions) are necessary for methacrylates.…”

Syndiospecific Polymerization of Methyl Methacrylate Catalyzed by Lanthanoid Thiolate Complexes Bearing a Hexamethylphosphoric Triamide Ligand

“…Thus, the coordination of HMPA ligand to lanthanide thiolate complexes improves the syndiospecificity more effectively compared with similar coordination to magnesium of Grignard reagents. Among the HMPA-free complexes, it is notable that the europium(II) complex 4b shows a different selectivity of the polymerization that gives an isotactic PMMA (mm = 68%) in THF in good yield. , The 2[rr]/[mr] value of this polymer is 1.05, indicating the enantiomorphic site control …”