Inclusion Complex Formation between α‐Cyclodextrin and Biodegradable Aliphatic Polyesters

Summary: Inclusion complexes (ICs) between α‐cyclodextrin (α‐CD) and three kinds of biodegradable aliphatic polyesters with different sequence lengths of the monomeric repeating units poly(3‐hydroxypropionate) [P(3HP)], poly(4‐hydroxybutyrate) [P(4HB)] and poly(ε‐caprolactone)(PCL) were prepared by mixing a solution of α‐CD with that of the polymer, followed by stirring. The ICs were obtained as insoluble precipitates and characterized by FT‐IR, WAXD and DSC. All measurements showed that the polymer chains of all three kinds of polyester were included into the α‐CD cavity and formed ICs with different stoichiometries. WAXD patterns and thermal analysis indicated that these ICs possessed a channel structure and the crystallization of the polyester chains was suppressed upon inclusion into the α‐CD cavity. Expansion of the FT‐IR spectra of α‐CD‐PCL IC. Ex: experimental result; Cr: crystalline component; Am: amorphous component; Hb: hydrogen‐bonded component; OH: hydroxyl component (water). magnified image Expansion of the FT‐IR spectra of α‐CD‐PCL IC. Ex: experimental result; Cr: crystalline component; Am: amorphous component; Hb: hydrogen‐bonded component; OH: hydroxyl component (water).