Preparation and sorption properties of tunable polyester copolymers containing β‐cyclodextrin

Abstract

Polyester copolymers were prepared with b-cyclodextrin (b-CD) and sebacoyl (SCl) or terephthaloyl (TCl) chloride cross linker agents using a simple, one-pot synthesis. Variation of the mole ratios (i.e., 1 : 1, 1 : 2, 1 : 3, 1 : 6, and 1 : 9) of b-CD to diacid chloride linker units resulted in copolymers with differing solubility and chemical stability in aqueous solution. The sorption properties of copolymers such as 1 : 6 and 1 : 9 SCl, and 1 : 9 TCl materials were investigated because of their relative insolubility and resistance to hydrolysis at pH 4.6. The monolayer sorption capacity (Q m ) of the copolymers varied according to the nature of the cross linker and the relative mole ratio of monomers. Q m values obtained from the Sips isotherm model range from 2.7 to 5.2 mmol/ g for the sorption of p-nitrophenol at 295 K and approach the value of Q m for a commercially available granular activated carbon sorbent.

Preparation and sorption studies of polyester microsphere copolymers containing β-Cyclodextrin

“…The intensity of the carbonyl signature increases for each copolymer as the linker content increases, in accordance with the relative mole ratio of b-CD and linker. The foregoing results are in agreement with those reported previously [19,33] for polyester-based copolymers prepared in polar organic solvents (i.e. non-emulsion conditions).…”

“…The incremental Dd values of the monomer units correspond to an increasing degree of substitution of the b-CD annulus due to cross linking for each type of linker unit. The NMR spectra of the water insoluble copolymers were obtained in DMSO-d 6 , and compared with spectra for copolymers obtained in organic solvents [19,33]. The spectra show some broad peaks at $5.7 and 4.4 ppm for the hydroxyl groups on b-CD, as previously reported for b-CD in DMSO-d 6 by Schneider et al [32] The relative composition of copolymers (i.e.…”

“…In contrast to the water soluble copolymers TCl-1 and SCl-1, copolymers prepared at higher cross linker content (i.e. >1:1) are generally insoluble in water but have good solubility in polar organic solvents such as DMSO [19]. Copolymers prepared using w/o microemulsion conditions relative to those prepared in organic solvents differ according to their morphology, as described previously [13].…”

“…The cross linking efficiency of TCl is greater than SCl at these conditions, and may be due to differences in reactivity of the cross linkers in a w/o microemulsion. Differences in the reactivity of TCl and SCl was previously reported for SCl and TCl in dimethylacetamide [19]. For TCl-based copolymers, the monomer ratio was calculated from the integration ratios of the H 1 nuclei of b-CD (1/7 area) and the aromatic nuclei of TCl (1/4 area).…”

“…The sorption properties and structure of various copolymer/ PNP complexes were studied in aqueous solution using UV-Vis and 1 H NMR spectroscopy. This study contributes to a significantly improved understanding of the interactions between PNP and polyester-based copolymer containing b-CD [19] which may be applied to a wide range of CD-based sorbent materials.…”