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I. N. Topchieva, I. G. Panova, V. V. Spiridonov, Ye. V. Matukhina, B. I. Kurganov
The evaluation of molecular
mass of non-covalent columnar polymers based on b-cyclodextrin
using the determination of their polymer inclusion compexes aggregation rate
with polypropylene glycol
Abstract
Non-covalent columnar polymers (NCP) based on
cyclodextrins (CD) are polymer assemblies of molecules with prolonged waste
channels, their width being determined by the diameter of the cavity of parent
CDs. The repeating chain of NCP is a molecule of CD. For NCP generated by
method of exclusion of polymer ligand from corresponding inclusion complexes
(IC) of b-CD,
(NCPex), the length of
polymer chain is expressed by the number of CD molecules in the single polymer
chain, n, is determined by the dimensions of polymer ligand,
polypropylene glycol (PPG), and equals to the polymerization degree divided by
two. The determination of the molecular mass of NCP, synthesized by method of
precipitation (NCPpr) is made difficult by the fact that in solution they
exist not as single molecules but as aggregates. In the present paper for the
evaluation of NCPpr molecular mass (MM) we used indirect method based on the
determination of the aggregation rate of IC, formed due to the interaction of
NCP with PPG of fixed MM, in this case PPG 1000. The comparison of the
aggregation rate of IC including NCPex, that were synthesized using PPG
of various MM, with PPG 1000 with the rate of aggregation of IC based on NCPpr offers the
possibility to evaluate MM
of single polymer chains. Plotting the calibration curve was performed based on
the fact that samples of NCPpr contain ~30% of monomer b-CD. It was shown that MM of PPG corresponding to NCPpr is 1320 Da. It means
that a single chain of NCPpr includes 11-12 molecules of b-CD.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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