A. Harada et al., PREPARATION AND CHARACTERIZATION OF INCLUSION COMPLEXES OF POLY(PROPYLENE GLYCOL) WITH CYCLODEXTRINS, Macromolecules, 28(24), 1995, pp. 8406-8411
beta-Cyclodextrin (beta-CD) and gamma-cyclodextrin (gamma-CD) form inc
lusion complexes with poly(propylene glycol)s (PPG) of various molecul
ar weights to give stoichiometric compounds in crystalline states. alp
ha-Cyclodextrin (alpha-CD) did not form complexes with PPG of any mole
cular weight. beta- and gamma-CD did not form complexes with the low m
olecular weight analogs, such as propylene glycol, di(propylene glycol
), and tri(propylene glycol). The yields of the complexes of beta- and
gamma-CD with PPG increased with increasing molecular weight (MW) of
the PPG and reached a maximum at about MW 1000; yield decreased with a
further increase in the MW. They were isolated and found to be 2:1 (m
onomer unit:CD). The complexes were characterized by IR, H-1 NMR, C-13
NMR, C-13 CP/MAS NMR, and C-13 PST/MAS NMR spectra and X-ray (powder)
, thermal, and elemental analyses. Complex formation of CDs with PPG d
erivatives has also been studied. The structures of the complexes are
discussed. Complex formation of beta-CD with atactic and isotactic PPG
has been compared.