Preparation and Characterization of Inclusion Complexes of Aliphatic Polyesters with Cyclodextrins

Abstract

Cyclodextrins (CDs) were found to form inclusion complexes with aliphatic polyesters [−O(CH2)xOCO(CH2)4CO]n (where x = 2, 3, or 4) to give crystalline compounds. α- and γ-CD formed complexes with these polyesters in high yields, although β-CD gave complexes in moderate yields. Although the yields of the complexes of α-CD with poly(trimethylene adipate) (PTA) (x = 3) and poly(1,4-butylene adipate) (PBA) (x = 4) decreased with increasing molecular weight, α-CD formed complexes with poly(ethylene adipate) (PEA) (x = 2) in high yields even at higher molecular weights. The yields of the complexes of γ-CD with these polyesters showed a maximum at the molecular weight of 1000. The complexes were isolated and characterized by FTIR, 1H NMR, 13C CP/MAS NMR spectra, and X-ray diffraction studies. The inclusion modes are discussed.