Abstract:

Poly [ ethylene glycol-b- （L-lactide） ] （PELA） was synthesized, with monomethoxypolyethylene glycol （MPEG）, stannous octoate and L-lactide as the materials. The product then reacted with α-cyclodextrin to form an inclusion complex. Moreover, the structure and properties of the complex were characterized by infrared spectrosco- py （IR）, differential scanning calorimetry （DSC）, X-ray diffractometry （XRD） and 1H nuclear magnetic resonance （1H NMR） spectroscopy. It is shown that PELA polymer chains are included inside the molecular tube formed by multiple α-cyclodextrin molecules aligning into close-packed hexagonal crystalline structures, that there is no crystallization and melting behaviors in the complex because the chain motion of PELA is confined by α-cyclo- dextrin molecules, and that the molar ratio of ot-cyclodextrin to the repeating unit of polyethylene glycol block in the inclusion complex is 1 ： 4. 7. In conclusion, PELA is capable of forming inclusion complex with α-cyclodextrin.

Key words: polylactic acid, polyethylene glycol, α-cyclodextrin, inclusion complex, poly [ ethylene glycol-b- （ L- lactide） ]