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Cyclodextrins in polymer synthesis: Free radical polymerization of methylated β ‐cyclodextrin complexes of methyl methacrylate and styrene, controlled by dodecanethiol as the chain‐transfer agent in aqueous medium
Author(s) -
Glöckner Patrick,
Ritter Helmut
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20001101)201:17<2455::aid-macp2455>3.0.co;2-x
Subject(s) - chemistry , polymer chemistry , chain transfer , monomer , methyl methacrylate , styrene , radical polymerization , polymerization , transfer agent , cyclodextrin , catalytic chain transfer , living polymerization , methacrylate , polymer , organic chemistry , copolymer
Methylated β ‐cyclodextrin (me‐ β ‐CD) was used to complex the hydrophobic monomers methyl methacrylate ( 1 ) or styrene ( 2 ) yielding the water‐soluble 1 : 1‐host/guest complexes methyl methacrylate/me‐ β ‐CD ( 1 a ) and styrene/me‐ β ‐CD ( 2 a ), respectively. In addition, the hydrophobic chain‐transfer agent dodecanethiol ( 3 ) was complexed by two equivalents of me‐ β ‐CD yielding the water‐soluble dodecanethiol/me‐ β ‐CD ( 3 a ). The included monomers were polymerized in water by a free‐radical mechanism in the presence of 3 a as the chain‐transfer agent. The chain‐transfer constants were determined. In order to evaluate these results, the chain‐transfer constants of 3 were also determined in the case of the corresponding uncomplexed monomers 1 and 2 in organic solution. It was found that the chain‐transfer constants of 1 a and 2 a (Cs 1a = 0.5 ± 0.2, Cs 2a = 2.2 ± 0.3) are significantly lower compared with the values obtained from the polymerizations of the corresponding uncomplexed monomers 1 and 2 in organic solution (Cs 1 = 3.1 ± 0.3, Cs 2 = 3.4 ± 0.3).