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4719857 
Journal Article 
Tracing Arm-Growth Initiation in Z-RAFT Star Polymerization by NMR: The Impact of the Leaving R-Group on Star Topology 
Boschmann, D; Maenz, M; Poeppler, AnnC; Soerensen, N; Vana, P 
2008 
Yes 
Journal of Polymer Science. Part A, Polymer Chemistry
ISSN: 0887-624X
EISSN: 1099-0518 
46 
21 
7280-+ 
WOS:000260587100038 
Arm-growth initiation in six-armed Z-RAFT star polymerization of styrene-d(8) was followed via the disappearance of H-1 NMR signals of the leaving group at their original position. These measurements revealed a dramatic impact of the leaving group on star polymer topology. Phenylethyl as leaving group induced formation of completely initiated stars already after 8% of monomer conversion. Benzyl as leaving group, however, drastically slows down arm-growth initiation, resulting in fully initiated star polymers only after about 60% of monomer conversion. Below that value, star-polystyrene of the expected topology cannot be generated with benzyl as leaving group. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.] Published online 25 September 2008 
living radical polymerization; NMR; radical polymerization; reversible addition-fragmentation chain transfer (RAFT); star polymers