Synthesis of highly isotactic poly(N,N‐diethylacrylamide) by anionic polymerization with grignard reagents and diethylzinc

Controlled Anionic Block Copolymerization with N,N‐Dialkylacrylamide as a Second Block

“…The reason for the elevated transition temperature is due to the isotactic structure of the PDEAAm block, whereas the transition temperature of heterotactic PDEAAm was observed to be around 30 8C. [5] The apparent equilibrium hydrodynamic radius of the resulting micelle-like aggregates was 143 nm for No. 24, 87 nm for No.…”

“…Hysteresis of heating and cooling cycle was found in isotactic PDEAAm as well. [5] Conclusion Novel block copolymers based on PS, PtBMA, P2VP, or PEO as the first block and either PDMAAm or PDEAAm as the second block were synthesized. When the polymerizations were carried out in THF gel formation was observed.…”

“…[1][2][3] Polymerizations using initiators with caesium as the counterion proceed without significant chain transfer and termination. [3] In the last decade, well-controlled ''ligated'' polymerization of DAlAAm was successfully carried out by using organolithium or organopotassium initiators as well as Grignard reagents in the presence of Lewis acid additives [diethylzinc (ZnEt 2 ) [4,5] or triethylborane [6] ]. The effect of the Lewis acid additive on the anionic polymerization process results in slow propagation reaction and narrow molecular weight distribution (MWD) of the polymers.…”

“…As a consequence, the resulting polymers possess mostly predicted M n 's. [4][5][6] Hence, the polymers produced with organolithium initiators alone are rich in isotactic configuration, whereas the addition of ZnEt 2 strongly reduces the isotacticity and increases the degree of syndio-and heterotacticity. [4] In this way, a group of Japanese scientists [4][5][6] developed a synthetic route for well-controlled polymerization of DAlAAm, which has highly regulated stereostructures.…”

Mechanistic Perspectives on Stereocontrol in Lewis Acid-Mediated Radical Polymerization

“…148,149 Remarkably, for the radical polymerization of N,N-disubstituted acrylamides, such as DMA (which are polymerizable directly with anionic and coordination processes), the isotactic control afforded by LAs is comparable to that obtained via anionic polymerization under much more demanding conditions. 150,151 For instance, Okamoto and coworkers reported that an isotactic content of m ¼ 88% could be obtained during the radical polymerization of DMA in methanol at 0 C by using 10 mol% Yb(OTf) 3 as a control agent. 146,147 Subsequent work by Matyjaszewski and coworkers demonstrated that either RAFT or ATRP could be used concurrently with either Y(OTf) 3 or Yb(OTf) 3 to simultaneously control the tacticity, molecular weight distribution, and chain-end functionality.…”