ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 7, pp. 1111!1115. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + T.E. Sukhanova, S.V. Bronnikov, A.I. Grigor’ev, G.N. Gubanova, M.P. Perminova, N. Marangoci, M. Pinteala, V. Harabagiu,
B. Simionescu, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 7, pp. 1141 !1146.
AND POLYMERIC MATERIALS
Synthesis, Structure, and Thermal Properties of Polyrotaxanes
Derived from >-Cyclodextrin and Polydimethylsiloxane
T. E. Sukhanova, S. V. Bronnikov, A. I. Grigor’ev, G. N. Gubanova, M. P. Perminova,
N. Marangoci, M. Pinteala, V. Harabagiu, and B. Simionescu
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Petru Poni Institute of Macromolecular Chemistry, Ia¸si, Romania
Received March 12, 2007
Abstract-Supramolecular inclusion complexes, polyrotaxanes, of b-cyclodextrin with modified polydi-
methylsiloxane were prepared. The structure and thermal properties of these complexes were studied as
influenced by the preparation conditions, component ratio, and molecular weight of the polymer.
Synthesis and preparation of polymeric supra-
molecular complexes, polyrotaxanes (PRot), contain-
ing macromolecular rins strung on linear polymers
with bulky terminal groups (blockers) attracts great
Cyclodextrins (CDs), cyclic oligosaccharides
consisting of D-glucopyranoside units bound by
a-1,4-glucoside bond , are widely used as the
cyclic component in matrix synthesis of PRot .
CD molecules have a shape of truncated cone 7 A
long and from 4.5 to 8.5 A in internal diameter (de-
pending on the modification: a-, b-, and g-CD). These
compounds contain hydroxy groups on the internal
and external sides of their molecules and hydrocarbon
and ether groups inside the cone. The internal surface
of CD molecules is hydrophobic and the external sur-
face is hydrophilic . The linear components used
for preparation of inclusion complexes of CD usually
have two hydrophilic terminal groups and their inter-
nal part is hydrophobic. When both components are
dissolved in a polar solvent (e.g., in water), the hy-
drophobic part of the linear macromolecule is strung
on CD, whereas its hydrophilic parts do not enter in-
side the ring.
Supramolecular host3guest complexes formed by
stringing CD (host) on linear polymer chains (guest)
of different structure and molecular weights, such as
poly(ethylene oxide) , poly(propylene oxide) ,
poly-e-caprolactam , etc., have been prepared and
characterized. These complexes are used as supports
for preparing silicate materials whose pore size de-
pends on the pH of the reaction mixture , deliver-
ing pharmaceuticals to required parts of stomach ,
as molecular switches [10, 11], etc.
Polyrotaxanes of b-CD and polydimethylsiloxane
(PDMS) were prepared for the first time by Harada
et al. . They found that the geometrical size of
a-CD cavity did not match the cross section diameter
of PDMS macromolecule and hence the a-CD3PDMS
complexes were not formed. At the same time, b-CD
forms inclusion complexes with low-molecular-weight
< 700). g-CD can be strung on PDMS
of higher molecular weight (up to M
= 3300). The
maximal ratio of CD to monomer units of the polymer
in the inclusion complexes is 1.5 .
The aim of this study was to prepare PRots of
b-CD with PDMS modified with epoxy groups
(PDMSE) and to examine their supramolecular struc-
ture, morphology, and thermal properties by physical
The main component of the inclusion complex,
linear PDMSE, was prepared by stepwise synthesis
shown in Scheme 1.
The first step is the reaction of octamethylcyclo-
tetrasiloxane with 1,1,3,3-tetramethyldisiloxane at
room temperature for 4 h in the presence of 2 vol %
to form PDMS with different molecular
weights, having reactive Si3H terminal group.