Inclusion complex formation between α-cyclodextrin and biodegradable aliphatic polyesters

Inclusion complexes (ICs) between alpha-cyclodextrin (alpha-CD) and three kinds of biodegradable aliphatic polyesters with different sequence lengths of the monomeric repeating units poly(3-hydroxypropionatc) [P(3HP)], poly(4-hydroxybutyrate) [P(4HB)] and poly(epsilon-caprolactone)(PCL) were prepared by mixing a solution of alpha-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 polyrner chains of all three kinds of polyester were included into the alpha-CD cavity and formed ICs with different stoichiometries. WAX-D 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 alpha-CD cavity.