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Chain Transfer to Polymer and Branching in Controlled Radical Polymerizations of n -Butyl Acrylate
- Source :
- Macromolecular Rapid Communications. 30:2002-2021
- Publication Year :
- 2009
- Publisher :
- Wiley, 2009.
-
Abstract
- Chain transfer to polymer (CTP) in conventional free-radical polymerizations (FRPs) and controlled radical polymerizations (ATRP, RAFT and NMP) of n-butyl acrylate (BA) has been investigated using 13C NMR measurements of branching in the poly(n-butyl acrylate) produced. The mol-% branches are reduced significantly in the controlled radical polymerizations as compared to conventional FRPs. Several possible explanations for this observation are discussed critically and all except one refuted. The observations are explained in terms of differences in the concentration of highly reactive short-chain radicals which can be expected to undergo both intra- and inter-molecular CTP at much higher rates than long-chain radicals. In conventional FRP, the distribution of radical concentrations is broad and there always is present a significant proportion of short-chain radicals, whereas in controlled radical polymerizations, the distribution is narrow with only a small proportion of short-chain radicals which diminishes as the living chains grow. Hence, irrespective of the type of control, controlled radical polymerizations give rise to lower levels of branching, when performed under otherwise similar conditions to conventional FRP. Similar observations are expected for other acrylates and monomers that undergo chain transfer to polymer during radical polymerization.
- Subjects :
- Acrylate
Polymers and Plastics
Radical
Organic Chemistry
Degenerative chain transfer
Radical polymerization
Chain transfer
Photochemistry
Branching (polymer chemistry)
chemistry.chemical_compound
Living free-radical polymerization
chemistry
Polymer chemistry
Materials Chemistry
Reversible addition−fragmentation chain-transfer polymerization
Subjects
Details
- ISSN :
- 10221336
- Volume :
- 30
- Database :
- OpenAIRE
- Journal :
- Macromolecular Rapid Communications
- Accession number :
- edsair.doi...........7915530db1a0a1890d01832f0d3ef2c5