Proton Transfer Anionic Polymerization of Methyl Methacrylate with Ligands for Dual Control of Molecular Weight and Tacticity

Katsutoshi Sagawa; Mineto Uchiyama; Hironobu Watanabe; Chihiro Homma; Masami Kamigaito

doi:10.1021/prechem.4c00066

Proton Transfer Anionic Polymerization of Methyl Methacrylate with Ligands for Dual Control of Molecular Weight and Tacticity

Precis Chem. 2024 Oct 15;2(12):628-633. doi: 10.1021/prechem.4c00066. eCollection 2024 Dec 23.

Authors

Katsutoshi Sagawa¹, Mineto Uchiyama¹, Hironobu Watanabe¹, Chihiro Homma¹, Masami Kamigaito¹

Affiliation

¹ Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.

Abstract

Dual control of the molecular weight and tacticity in proton transfer anionic polymerization (PTAP) of methyl methacrylate (MMA) was investigated by using various ligands in the presence of a bulky potassium base catalyst and an organic compound with a weakly acidic C-H bond as dormant species in toluene at 0 °C. The tacticity of the resulting poly(MMA) (PMMA) produced without ligands was nearly atactic (rr/mr/mm = 22/54/24). However, the use of 18-crown-6 as a ligand afforded predominantly syndiotactic PMMA (rr ≈ 58%), whereas the use of chiral bis(oxazoline) ligands gave slightly isotactic-rich PMMA (mm ≈ 32%). Molecular weight control of PMMA was achieved (Đ = 1.1-1.2) by adding 1,1-diphenylethanol as a reversible terminator while maintaining control of the tacticity with the above ligands. Stereoblock PMMA consisting of atactic and syndiotactic segments was successfully synthesized via sequential PTAP using macroinitiator/macro-CTA methods.