Synthesis of the Organic/Inorganic Hybrid Star Polymers and Their Inclusion Complexes with Cyclodextrins

In this study, we synthesized a series of the organic/inorganic hybrid star PCLs. These star PCLs can form inclusion complexes (ICs) with α- and γ-CD, but not with β-CD. These CD ICs were characterized by XRD, solid-state 13C CP/MAS NMR spectroscopy, 1H NMR spectroscopy, FT-IR spectroscopy, DSC, and TGA. Our results suggest that the PCL chains of these star polymers lose their original crystalline properties and were included inside the channels provided by the CDs to form a columnar crystalline structures. The stoichiometries (PCL:CD) that we determined by 1H NMR spectroscopy for all of the ICs with α- or γ-CD are higher than those of the corresponding CD/linear PCL ICs because of the steric hindrance around the bulky POSS core, which causes some of the e-caprolactone units near the core to be free from complexation with the CDs. From these analyses, we proposed some possible structures for the CD/star PCL ICs.