Polymerization by alkaline earth metal compounds-I. Studies on the polymerization of methylmethacrylate by triphenylmethyl metal derivatives and related compounds of calcium, strontium and barium

W. E. Lindsell, F. C. Robertson, I. Soutar, D. H. Richards

Research output: Contribution to journalArticle

Abstract

A series of related organo-alkaline earth metal compounds of formula (Ph3C)MX(THF)?, (M = Ca, Sr, Ba; X = Cl: M = Ca, Sr; X = Br: M = Ba; X = CPh3), has been isolated and characterized using analytical and spectroscopic techniques. The polymerization of methylmethacrylate (MMA) has been studied using these organometallic compounds as initiators. Investigations of the tacticity variations of polymethylmethacrylate (PMMA) produced in 1,2-dimethoxyethane or tetrahydrofuran (THF) at 210 K have shown that the syndiotacticity is higher in the former solvent, decreases with the following changes in initiator composition: Ca > Sr = Ba; Cl > Br; in THF, it is dependent on the monomer concentration. The molecular weight distributions of the PMMA samples are broad and have distinct bi- or poly-modal features. The polymerization process appears to be anionic in nature but the evidence suggests that more than one type of propagation occurs and mechanistic aspects are discussed. Polymerization of bulk MMA by these same initiators is also reported. The initiators RMX(THF)n (M = Sr, R = Me, n = 3 or R = Et, n = 2) and (C3H5)SrBr(THF)2 are shown to be inefficient for polymerization of MMA. The glass transition temperatures of a range of PMMA samples of differing tacticity are presented and discussed. © 1981.

Original languageEnglish
Pages (from-to)107-113
Number of pages7
JournalEuropean Polymer Journal
Volume17
Issue number2
Publication statusPublished - 1981

Fingerprint Dive into the research topics of 'Polymerization by alkaline earth metal compounds-I. Studies on the polymerization of methylmethacrylate by triphenylmethyl metal derivatives and related compounds of calcium, strontium and barium'. Together they form a unique fingerprint.

  • Cite this