title: Encapsulation of CO2 into amorphous alpha-cyclodextrin powder at different moisture contents - Part 2: Characterization of complexed powders and determination of crystalline structure.
abstract: This study aims to characterize CO2-α-cyclodextrin (α-CD) inclusion complexes produced from amorphous α-CD powder at moisture contents (MC) close to or higher than the critical level of crystallization (e.g. 13, 15 and 17% MC on wet basis, w.b.) at 0.4 and 1.6MPa pressure for 72h. The results of (13)C NMR, SEM, DSC and X-ray analyses showed that these MC levels were high enough to induce crystallization of CO2-α-CD complexed powders during encapsulation, by which amount of CO2 encapsulated by amorphous α-CD powder was significantly increased. The formation of inclusion complexes were well confirmed by results of FTIR and (13)C NMR analyses through an appearance of a peak associated with CO2 on the FTIR (2334cm(-1)) and NMR (125.3ppm) spectra. Determination of crystal packing patterns of CO2-α-CD complexed powders showed that during crystallization, α-CD molecules were arranged in cage-type structure in which CO2 molecules were entrapped in isolated cavities.
authors.affiliation: School of Agriculture and Food Sciences, The University of Queensland, QLD 4072, Australia.
authors.forename: Thao M
authors.initials: TM
authors.lastname: Ho
authors.affiliation: School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia.
authors.forename: Tony
authors.initials: T
authors.lastname: Howes
authors.affiliation: Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, QLD 4072, Australia.
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Jack
authors.affiliation: School of Agriculture and Food Sciences, The University of Queensland, QLD 4072, Australia. Electronic address: b.bhandari@uq.edu.au.
authors.forename: Bhesh R
authors.initials: BR
authors.lastname: Bhandari
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D003460:Crystallization; D009682:Magnetic Resonance Spectroscopy; D011208:Powders; D014867:Water; D047391:alpha-Cyclodextrins / Q000737:chemistry*
chemical_list: D011208:Powders; D047391:alpha-Cyclodextrins; D014867:Water; D002245:Carbon Dioxide; C032613:alpha-cyclodextrin
keywords: Amorphous α-cyclodextrin; Carbon dioxide; Complexed powder; Crystal packing; Solid encapsulation