Polyrotaxanes composed of β-cyclodextrin and polydimethylsiloxanes:: synthesis, morphology and thermal behavior

Epoxy-terminated polydimethylsiloxanes (E-PDMSs) of different molecular weight M-n were proved to undergo inclusion complexation into the inner cavity of beta-cyclodextrin (beta-CD), resulting in polyrotaxanes (PRots). The dethreading of the macrocycle was prevented by blocking the siloxane chain with a bulky substituent derived from 4-aminophenyltriphenyl methane (APhTPhM). As revealed by thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy (SEM), wide-angle X-ray diffraction and statistical analysis of SEM images, the thermal properties and the morphology of polyrotoxanes are dependent upon M-n, beta-CD/E-PDMS molar ratio and the presence of free beta-CD in the complexes.