6533b838fe1ef96bd12a4e5e

RESEARCH PRODUCT

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

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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 (Cs1a = 0.5 ± 0.2, Cs2a = 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 (Cs1 = 3.1 ± 0.3, Cs2 = 3.4 ± 0.3).