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

Abstract

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).

Influence of β‐Cyclodextrin on the Free‐Radical Copolymerization of N‐(4‐Methylphenyl)maleimide with N‐Vinylpyrrolidone in Water

“…Radical polymerization of substituted vinyl monomers in bulk, solution, or in dispersion to yield various polymeric products is a highly important field of ongoing practical and scientific interest. In addition to that, water‐based free‐radical homo‐ and copolymerization of suitable vinyl monomers as guests in the cavity of cyclodextrins (CD) as host molecules was developed in recent years . Our previous work has shown already that the reactivity ratios of CD‐mediated (meth)acrylate polymerization may differ significantly from the r values obtained from corresponding copolymerizations of uncomplexed monomers …”

Semicontinuous Emulsion Polymerization of Butyl Methacrylate and 1, 3-Butadiene in the Presence of Cyclodextrins and Cytocompatibility of Dicarboxylic Acid Telechelic Oligo(butyl Methacrylate)s Derived from Ozonolysis of the Latexes

“…Several examples of polymerizations in water of hydrophobic monomers have been reported. Thus, Ritter et al formed CD‐monomer complexes and then polymerized these using radical polymerizations 10–19. These polymerizations used the unique solubilizing power of CDs so that it was possible to produce aqueous solutions of the CD‐monomer complexes formed from monomers that are otherwise water insoluble.…”

Cyclodextrins in Polymer Synthesis: Free Radical Polymerization of β‐Cyclodextrin Complexes of Photosensitive Mesoionic 6‐Oxo‐1,6‐dihydropyrimidin‐3‐ium‐4‐olates in Aqueous Medium

“…In order to obtain information about the mechanism, the kinetics of the polymerization of various monomers29,30 as well as the influence of chain‐transfer agents31,32 was investigated. In addition, examples whereby CDs hinder the polymerization are known 33.…”