Protection and polymerization of functional monomers, 23. Synthesis of well‐defined poly(2‐hydroxyethyl methacrylate) by means of anionic living polymerization of protected monomers

Abstract

AbstractAnionic polymerizations of 2‐[(trimethylsilyl)oxy]ethyl methacrylate (1), 2‐[(tert‐butyldimethylsilyl)oxy]ethyl methacrylate (2), and 2‐[(methoxymethyl)oxy]ethyl methacrylate (3), the protected forms of 2‐hydroxyethyl methacrylate (HEMA), were carried out in THF at −78°C with 1,1‐diphenylhexyllithium or 1,1‐diphenyl‐3‐methylpentyllithium in the presence of LiCl. The resulting poly(1–3)s were found to possess predictable molecular weights and very narrow molecular weight distributions. The sequential polymerizations of tert‐butyl methacrylate with the anionic propagating ends of poly(1–3) gave block copolymers in quantitative efficiency. Thus, the anionic polymerizations of 1–3 proceeded without transfer and termination reactions to afford stable living polymers. Complete hydrolysis of the protective groups of poly(1–3)s produced linear poly(HEMA) quantitatively. Novel well‐defined di‐ and triblock copolymers containing hydrophobic [polystyrene, poly(4‐octylstyrene), polyisoprene] and hydrophilic segments [poly(HEMA)] were also prepared by sequential polymerization of the corresponding hydrophobic comonomers with 1, followed by deprotection.