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Viscosity changes of aqueous carboxymethyl starch by partial crosslinking and montmorillonite addition
Author(s) -
Zdanowicz Magdalena,
Spychaj Tadeusz
Publication year - 2014
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.40793
Subject(s) - aqueous solution , montmorillonite , rheology , polymer chemistry , viscosity , starch , chemistry , materials science , nuclear chemistry , intrinsic viscosity , organic chemistry , polymer , composite material
Slightly crosslinked carboxymethyl starch (cCMS) with degree of substitution (DS) 0.8–0.9 was prepared using mono‐ and di‐chloroacetic acids (MCA and DCA, respectively). Constant molar ratio of halogenated acetic acid derivatives to anhydroglucosidic unit (AGU) was adjusted (MCA+DCA):AGU=1.75:1; whereas, DCA:AGU ratio was changed in a range 0–0.10:1. The viscosity of 2 wt % cCMS aqueous solutions increased substantially for very slightly crosslinked product (DCA:AGU molar ratio 0.0075), in comparison to unmodified CMS, up to 170,000 mPa·s at 1 rpm, and 16,000 mPa·s, respectively. Some viscosity decrease of cCMS solutions during storing was observed. The explanation of this phenomenon was discussed and supported by 1 H NMR results. The rheological properties of cCMS solutions as well as aqueous cCMS/clay dispersions with various type of montmorillonite (MMT): sodium, calcium and organophilized as shear‐thinning systems were evaluated on a basis of power law model. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40793.