Anionic polymerization of (meth)acrylic monomers. 7. Macrocyclic crown ethers as promoters of the living polymerization of methyl methacrylate using monofunctional initiators

Abstract

It has been previously shown that µ-coordinating inorganic salts, such as LiCl, were effective in preventing the anionic polymerization of methacrylic esters and hindered alkyl acrylates from being disturbed by secondary transfer and termination reactions. That strategy has opened the way to the "living" polymerization of these monomers and their controlled sequential polymerization with monomers lacking a carbonylconjugated group. That control is however limited to THF at low temperatures for methyl methacrylate and tert-butyl acrylate. It is reported now that the polymerization mechanism remains strictly controlled in apolar solvents, such as toluene, and at temperatures as high as 0 °C, when crown ethers are used in relation to their capability of chelating the alkali-metal counterion and surrounding it with a steric barrier blocking a large enough space area around the metal-containing ion pair.

Anionic polymerization of methacrylic monomers: characterization of the propagating species

“…2. σ-type ligands, that form coordinative complexes with the metal counterion of the active species: crown ethers [50] and kryptands [51]. 3.…”

Anionic polymerization of methyl methacrylate using tetrakis[tris(dimethylamino)phosphoranylidenamino] phosphonium (P5+) as counterion in tetrahydrofuran

“…One possibility is the use of various ligands in conjunction with classical anionic initiators. r-Ligands, such as crown ethers 6) , cryptands 7,8) , tertiary amines 9,10) ; l-ligands, such as alkali alkoxides 11,12) halides 2, 13) , perchlorates 14,15) , aluminum alkyls [16][17][18][19] , and r, l-ligands, such as alkoxyalkoxides [20][21][22][23] , aminoalkoxides 24) , and silanolates [25][26][27] have been used with much success.…”

The effect of TMEDA on the kinetics of the anionic polymerization of methyl methacrylate in tetrahydrofuran using lithium as counterion

“…Teyssié and coworkers [19,20] performed the polymerization of MMA in presence of crown ethers and obtained PMMA with a narrow molecular weight distribution with good control of the molecular weight. However, no kinetic data are available.…”