caa a22 4500 465788432 CHVBK 20180323112016.0 cr unu---uuuuu 170327e19900501xx s 000 0 eng 10.1007/BF00419972 doi (NATIONALLICENCE)springer-10.1007/BF00419972 Retraction of the claim of ring expansion polymerization of isobutylene [Elektronische Daten] [A. Fehérvári, R. Faust, J. Kennedy] Some three years ago in a preliminary report from this laboratory we have proposed that the polymerization of isobutylene (IB) by the γ-tolyl-γ-valerolactone/BCl3 initiating system in CH3Cl or CH2Cl2 diluents at-30°C proceeds in a living manner by an unusual ring expansion mechanism and produces macrocyclic polyisobutylenes (PIBs) [1]. Extensive follow-up research confirmed the living nature of the polymerization, however, has failed to confirm the results of a key preliminary experiment upon which the proposition of macrocyclic polymer structure was based. Thus the results of a comparative hydrolysis/GPC experiment carried out with a relatively low molecular weight (Mn=5,400) PIB at -30°C under a blanket of N2 which gave a lower apparent molecular weight after hydrolysis than the original sample before hhydrolysis, could not be confirmed with higher molecular weight samples, i.e., with Mn=12,000, 17,000 and 30,000. As a consequence we wish to retract our earlier claim in regard to the synthesis of macrocyclic PIBs by certain lactone/BCl3 initiating systems but maintain that these polymerizations proceed in a living manner and yield asymmetric telechelic PIBs, e.g.,α-chloro-ε-carboxyl-PIBs [2]. Springer-Verlag, 1990 Fehérvári A. Institute of Polymer Science, University of Akron, 44325, Akron, OH, USA aut Faust R. Institute of Polymer Science, University of Akron, 44325, Akron, OH, USA aut Kennedy J. Institute of Polymer Science, University of Akron, 44325, Akron, OH, USA aut Polymer Bulletin Springer-Verlag 23/5(1990-05-01), 525-527 0170-0839 23:5<525 1990 23 289 https://doi.org/10.1007/BF00419972 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00419972 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fehérvári A. Institute of Polymer Science, University of Akron, 44325, Akron, OH, USA aut NATIONALLICENCE 700 1- Faust R. Institute of Polymer Science, University of Akron, 44325, Akron, OH, USA aut NATIONALLICENCE 700 1- Kennedy J. Institute of Polymer Science, University of Akron, 44325, Akron, OH, USA aut NATIONALLICENCE 773 0- Polymer Bulletin Springer-Verlag 23/5(1990-05-01), 525-527 0170-0839 23:5<525 1990 23 289 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer