Macromolecular thiolysis of oxiranes: End-group modification of RAFT prepared homopolymers

M Alyse Harvison, Thomas Paul Davis, Andrew B Lowe

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26 Citations (Scopus)

Abstract

Chain end modification of low molecular weight, RAFT-prepared polystyrene and poly(N,N-diethylacrylamide) by reaction with a range of small molecule epoxides is described. Two different routes are examined - initial dithioester end-group cleavage yielding the thiol-terminated polymer followed by catalytic thiolysis of the oxiranes and a one-pot procedure involving hydride cleavage of the dithioester end groups in the presence of an epoxide. High degrees of functionalization (>80 ) are observed via the first route in the presence of ZnCl 2 with molecular weight distributions remaining unimodal and narrow. However, with DBU as catalyst significant amounts of coupled species are observed. In contrast, the one-pot route, at least with poly(N,N- diethylacrylamide), resulted in essentially quantitative degrees of functionalization as evidenced by 1H NMR spectroscopy and qualitatively by FTIR spectroscopy. The effect of the newly introduced alcohol-functional end groups on the lower critical solution temperature of poly(N,N-diethylacrylamide) is demonstrated with cloud points tunable from ca. 27 to 47 ?C.
Original languageEnglish
Pages (from-to)1347 - 1354
Number of pages8
JournalPolymer Chemistry
Volume2
Issue number6
DOIs
Publication statusPublished - 2011
Externally publishedYes

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