Dynamics of isolated polycaprolactone chains in their inclusion complexes with cyclodextrins

Solid-state carbon NMR with magic-angle spinning has been used to study; th e structure and dynamics of semicrystalline polycaprolactone (PCL) and its inclusion complexes formed with alpha- and gamma -cyclodextrins (alpha- and gamma -CDs), which are shown to have channel structures occupied by single and two parallel, side-by-side chains, respectively. Guest-host magnetizat ion exchange has been observed, but the results differ substantially from t hose observed in semicrystalline polymers and blends. The conventional rela xation experiments and 2D wide-line separation NMR with windowless isotropi c mixing have been used to measure the chain dynamics. The results suggest that the intermolecular interactions restrict the dynamics of some atoms mo re than others, but that the chains in the complex are more mobile than in semicrystalline PCL. These results are compared with the inclusion compound formed between the model compound valeric acid and alpha -CD that is also a channel complex structure.