METHOD FOR MODIFYING POLYSACCHARIDES BY GRAFTING POLYETHERAMINES, POLYSACCHARIDES THUS MODIFIED AND PREPARATIONS COMPRISING SAME AND HAVING HEAT-SENSITIVE RHEOLOGICAL PROPERTIES

摘要

The invention relates to a method for modifying polysaccharides, which includes: (a) reacting a polysaccharide with a modified polyetheramine of type (X-R-C(O)NH)_bR' (wherein R' is a polyether and b = 1, 2 or 3, and X is a halogen, preferably Cl or Br, R is an alkyl group, possibly substituted, or an aromatic group, possibly substituted), in the presence of a base, preferably in the presence of water and isopropanol; (b) purifying the product obtained in the presence of NaCl, at least partially, by a membrane separation method, said purification being carried out at a pH of 9 to 13 (preferably of 10 to 12); (c) purifying the product obtained from step (b), at least partially, by a membrane separation method, said purification being carried out after neutralisation at a pH of 6 to 8 (preferably of 6.5 to 7.5), optionally after freeze-drying and washing the freeze-dried product (preferably with ethanol).