Complex formation of poly(ε-caprolactone) with cyclodextrin

Poly(ε-caprolactone) was found to form inclusion complexes with α-cyclodextrin to give crystalline compounds. The complexes are stoichiometric one-to-one (cyclodextrin: monomer unit) compounds. The yields of the complexes decreased with increasing the molecular weight of the polymer. They were characterized by IR, ¹H NMR, ¹³C CP/MAS NMR, and X-ray diffraction. The inclusion modes are discussed.