Rare‐earth‐metal‐initiated polymerizations of (meth)acrylates and block copolymerizations of olefins with polar monomers

Abstract

AbstractThe organo‐rare‐earth‐metal‐initiated living polymerization of methyl methacrylate (MMA) was first discovered in 1992 with (C5Me5)2LnR (where R is H or Me and Ln is Sm, Yb, Y, or La) as an initiator. These polymerizations provided highly syndiotactic (>96%) poly(methyl methacrylate) (PMMA) with a high number‐average molecular weight (Mn > 1000 × 103) and a very narrow molecular weight distribution [weight‐average molecular weight/number‐average molecular weight (Mw/Mn) < 1.04] quantitatively in a short period. Bridged rare‐earth‐metallocene derivatives were used to perform the block copolymerization of ethylene or 1‐hexene with MMA, methyl acrylate, cyclic carbonate, or ϵ‐caprolactone in a voluntary ratio. Highly isotactic (97%), monodisperse, high molecular weight (Mn > 500 × 103, Mw/Mn < 1.1) PMMA was first obtained in 1998 with [(Me3Si)3C]2Yb. Stereocomplexes prepared by the mixing of the resulting syndiotactic and isotactic PMMA revealed improved physical properties. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 1955–1959, 2001