Cyclodextrins in polymer synthesis: polymerization of methyl methacrylate under atom-transfer conditions (ATRP) in aqueous solution

Host guest complexes of methyl methacrylate (MMA) and randomly methylated β-cyclodextrin (m-β-CD, 1 a) were polymerized in aqueous medium using atom-transfer radical polymerization. Ethyl 2-bromoisobutyrate (EBIB) was used as an initiator, copper(I) bromide as the catalyst, and bipyridine (bipy) or 4,4′-di-(5-nonyl)-2,2´-bipyridine (dNbipy) as ligands. The unthreading of m-β-CD during the polymerization led to water-insoluble poly(methyl methacrylate) (PMMA). It was found that using dNbipy resulted in higher monomer conversion than using bipy as the ligand under similar conditions. Furthermore, it is shown that the polymerization of MMA under these conditions has a living character. The pol…

Cyclodextrins in polymer synthesis: free radical polymerization of cyclodextrin host-guest complexes of methyl methacrylate or styrene from homogenous aqueous solution

The polymerization of methylated β-cyclodextrin (m-β-CD) 1 : 1 host-guest compounds of methyl methacrylate (MMA) (1) or styrene (2) is described. The polymerization of complexes 1 a and 2 a was carried out in water with potassium peroxodisulfate (K2S2O8)/sodium hydrogensulfite (NaHSO3) as radical redox initiator at 60°C. Unthreading of m-β-CD during the polymerization led to water-insoluble poly(methyl methacrylate) (PMMA) (3) and polystyrene (4). By comparison, analogously prepared polymers from uncomplexed monomers 1 and 2 in ethanol as organic solvent with 2,2′-azoisobutyronitrile (AIBN) as radical initiator showed significantly lower molecular weights and were obtained in lower yields i…

Cyclodextrins in Polymer Synthesis: Supramolecular Cyclodextrin Complexes of Pyrrole and 3,4-Ethylenedioxythiophene and Their Oxidative Polymerization

Cyclodextrins in polymer synthesis: photocrosslinkable films via free radical copolymerization of methylated β-cyclodextrin-complexed styrene with sodium 4-(acrylamido)-phenyldiazosulfonate in aqueous medium

The copolymerization of a methylated-β-cyclodextrin (m-β-CD) 1:1 host-guest compound of styrene (1a) with various molar ratios of sodium 4-(acrylamido)-phenyldiazosulfonate (2) is described. The copolymerization of complex 1a with 2 was carried out in water with 2,2′-azobis(N,N′-dimethyleneisobutyramidine)-dihydrochloride as the free radical initiator at 40°C. Depending on the amount of 2 incorporated in the copolymer, water- or DMF-soluble copolymers of high molar mass were obtained. Irradiation of the copolymers with UV light in solution resulted in rapid decomposition of the azo chromophore, and irradiation of the polymers as films led to crosslinking and thus to insolubility.