Syntheses of Syndiotactic Poly (methyl methacrylate)s with Bulky Alkyllithiums

Abstract

In order to prepare highly syndiotactic Poly(methyl methacrylate) (PMMA) with narrow molecular weight distribution (MWD), polymerization of methyl methacrylate (MMA) was studied in tetrahydrofuran at -78°C using various alkyllithiums RLi, as initiators (R=1,1-diphenyl-3-methylpentyl, 1,1-diphenylhexyl, fluorenyl, indenyl, triphenylmethyl, 1,1,3-triphenylpropyl, 1,1-diphenyldecyl, benzyl, octyl, butyl). Initiators having bulky alkyl group such as 1,1-diphenyl-3-methylpentyllithium, 1,1-diphenylhexyllithium and fluorenyllithium polymerized MMA rapidly to give syndiotactic (syndiotactic triad ca. 85%) PMMAs with narrow MWD. Stereoregularities of the PMMAs were independent of the molecular weight of the polymer. The molecular weight of the polymer could be easily controlled up to 200,000. Polymerization of MMA with butyllithium or octyllithium proceeded slowly and gave a PMMA with broad MWD, which may be due to the side reaction of the initiator with the carbonyl group of MMA. © 1986, The Society of Polymer Science, Japan. All rights reserved.