CELLULOSE NANOFIBERS MODIFIED WITH SULFURIC ACID ESTERIFICATION METHOD AND CELLULOSE NANOFIBRES PRODUCTION METHOD Russian patent published in 2020 - IPC C08B15/00 C08B7/00 

FIELD: nanotechnology; cellulose industry.

SUBSTANCE: present invention relates to modified sulfuric acid esterification method of cellulose nanofibres and to method of producing cellulose nanofibres. Cellulose nanofibres have average fiber diameter in range of 1 nm to 500 nm and hydroxylic groups modified by sulfuric acid esterification method on cellulose nanofibres surfaces, viscosity of 0.3 wt % aqueous dispersion of cellulose nanofibres, at a measurement temperature of 25 °C, rpm of 2.6 rpm, is 500 mPa·s and more or in which the thixotropy index TI (2.6 rpm/26 rpm) of 0.3 wt % aqueous dispersion of cellulose nanofibres modified by sulfuric acid esterification at 25 °C ranges from 3 to 30. Present invention also provides a method of producing cellulose nanofibres, which involves impregnating cellulose with a fibrillating solution containing dimethylsulphoxide, at least one carboxylic acid anhydride selected from acetic anhydride and propionic anhydride, and sulfuric acid, for fibrillation of cellulose, and a method of producing modified cellulose nanofibres, comprising modifying surfaces of cellulose nanofibres via esterification or urethane.

EFFECT: invention enables to obtain cellulose nanofibres which are nanosized, have high degree of crystallinity and high aspect ratio, the method being a chemical method, for which there is no need for physical grinding, which is energy-saving and which can be executed in mild reaction conditions.

13 cl, 32 dwg, 4 tbl, 30 ex