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Role of polyacrylate starch copolymer in water sorption
Author(s) -
Ziderman I. Irving,
Belayche Janine
Publication year - 1986
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.1986.070320711
Subject(s) - copolymer , swelling , starch , swelling capacity , aqueous solution , saponification , acrylic acid , polymer chemistry , chemistry , sorption , chemical engineering , maize starch , materials science , nuclear chemistry , adsorption , organic chemistry , polymer , composite material , engineering
Abstract Water sorbence by saponified polyacrylonitrile‐grafted polysaccharides was studied in relation to practical end uses. Graft copolymers prepared from wheat flour, corn flour, cotton wool, and rayon fibers swelled to a gel, exhibiting a 10‐ to 20‐fold increase in sorbency over the starting materials. A further enhanced water capacity was obtained when homopolymer was not removed. Soaking the wheat flour copolymer in salts or dilute mineral acid nullified the enhanced water sorbence, which could be reversible restored by neutralization of acrylic acid functions with alkali. Swelling the copolymer in aqueous D ‐glucose did not impair its water capacity. The mechanism of swelling to a gel appears to involve electrolyte osmotic pressure generated by a Donnan equilibrium. Grafting starch elevated its heat of water vaporization above that of pure water, and increased its capacity to absorb water from ethanol‐water vapor at 40° above that of native starch. At higher temperatures, however, the dehydrating capacity decreased to that of native flour.