Advantages of Block Copolymer Synthesis by RAFT-Controlled Dispersion Polymerization in Supercritical Carbon Dioxide

Reversible addition–fragmentation chain transfer (RAFT)-controlled block copolymer synthesis using dispersion polymerization in supercritical carbon dioxide (scCO2) shows unprecedented control over blocking efficiency. For PMMA-b-PBzMA and PMMA-b-PSt the blocking efficiency was quantified by measuri...

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Bibliographic Details
Published inMacromolecules Vol. 46; no. 17; pp. 6843 - 6851
Main Authors Jennings, James, Beija, Mariana, Kennon, Jeremy T, Willcock, Helen, O’Reilly, Rachel K, Rimmer, Stephen, Howdle, Steven M
Format Journal Article
LanguageEnglish
Published Washington, DC American Chemical Society 10.09.2013
Subjects
Applied sciences
Exact sciences and technology
Organic polymers
Physicochemistry of polymers
Polymerization
Preparation, kinetics, thermodynamics, mechanism and catalysts
One pot reaction
Organic trithiocarbonate
Purity control
Polymerization under pressure
Experimental study
Methyl methacrylate copolymer
Optimization
Gel permeation chromatography
Operating conditions
Monodispersed polymer
Deconvolution
Free radical polymerization
Chain transfer
Dispersion polymerization
Diblock copolymer
Supercritical solvent
Methacrylate copolymer
High purity
Successive reaction
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Summary:Reversible addition–fragmentation chain transfer (RAFT)-controlled block copolymer synthesis using dispersion polymerization in supercritical carbon dioxide (scCO2) shows unprecedented control over blocking efficiency. For PMMA-b-PBzMA and PMMA-b-PSt the blocking efficiency was quantified by measuring homopolymer contaminants using the techniques of GPC deconvolution, gradient polymer elution chromatography (GPEC), and GPC dual RI/UV detection. A new, promising method was also developed which combined GPC deconvolution and GPEC. All techniques showed that blocking efficiency was significantly improved by reducing the radical concentration and target molecular weight. Estimated values agreed well with (and occasionally exceeded) theory for PMMA-b-PBzMA. The heterogeneous process in scCO2 appeared to cause little or no further hindrance to the block copolymerization procedure when reaction conditions were optimized. High blocking efficiencies were achieved (up to 82%) even at high conversion of MMA (>95%) and high molecular weight. These data compare favorably to numerous published reports of heterogeneous syntheses of block copolymers.
ISSN:0024-9297
1520-5835
DOI:10.1021/ma401051e