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New solvent for polyrotaxane. III. Dissolution of a poly(ethylene glycol)/cyclodextrin polyrotaxane in a calcium thiocyanate aqueous solution or N ‐methylmorpholine‐ N ‐oxide monohydrate
Author(s) -
Araki Jun,
Kataoka Toshiyuki,
Ito Kohzo
Publication year - 2007
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.26232
Subject(s) - aqueous solution , ethylene glycol , ethylene oxide , dissolution , chemistry , polymer chemistry , cellulose , solvent , ammonium thiocyanate , inorganic chemistry , organic chemistry , copolymer , polymer
Calcium thiocyanate [Ca(SCN) 2 ] aqueous solutions above 40 wt % and N ‐methylmorpholine N ‐oxide (NMMO) monohydrate, which are known to dissolve cellulose, were found to be good solvents for a polyrotaxane comprising α‐cyclodextrin and poly(ethylene glycol). The polyrotaxane could be dissolved up to 12 and 10 wt % in a 40 wt % Ca(SCN) 2 aqueous solution and NMMO, respectively. These are the first instances of a neutral aqueous solution and a cyclic amine oxide, respectively, that readily dissolve the polyrotaxane. These new good solvents, as well as other solvents of the polyrotaxane, except for dimethyl sulfoxide, are identical to those of cellulose, indicating that the dissolution mechanism of the polyrotaxane is dominated by intra‐ and intermolecular hydrogen bonding of the molecule similar to that of cellulose dissolution. The concentrated polyrotaxane solution in a 40 wt % Ca(SCN) 2 aqueous solution showed apparent thixotropy and spontaneous gelation of the solution caused by a gradual increase in its viscosity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007