Preparation and Characterization of Inclusion Complexes of Biodegradable Amphiphilic Poly(ethylene oxide)−Poly[(R)-3-hydroxybutyrate]−Poly(ethylene oxide) Triblock Copolymers with Cyclodextrins

Abstract

Inclusion complexes (ICs) of biodegradable amphiphilic poly(ethylene oxide)-poly[(R)-3-hydroxybutyrate]-poly(ethylene oxide) triblock copolymers with α-cyclodextrin (α-CD) or γ-cyclodextrin (γ-CD) were prepared from aqueous medium. The ICs were characterized by XRD, DSC, 13 C CP/MAS NMR, 1 H NMR, FTIR, and TGA. The results of XRD and 13 C CP/MAS NMR indicated that the ICs formed channel structure, and the α-CD or γ-CD molecules in the ICs adopted a more symmetric conformation compared with their uncomplexed states. As to the triblock copolymers, while the poly(ethylene oxide) blocks were included in the channel structure, the poly[(R)-3-hydroxybutyrate] block was partially threaded by α-CD or γ-CD, which was confirmed by the results of XRD, DSC, 1 H NMR, and FTIR. The formation of ICs led to an increase in the thermal stability of both cyclodextrins and the triblock copolymers.