METHOD FOR PRODUCING BIOPOLYMERIC HYDROGEL Russian patent published in 2021 - IPC C08B15/00 C08B15/10 C08B3/12 A61L15/28 C08J3/75 C08J9/00 

FIELD: chemistry.

SUBSTANCE: invention relates to production of hydrogels from cross-linked hydrophilic biopolymers capable of quickly absorbing water amount exceeding their dry mass by more than 10 times, and while remaining mechanically strong and elastic, maintain and restore its shape after squeezing up to 90 %. They can be used in industry, agriculture, horticulture, household goods, in cosmetics and medicine, in the manufacture of packing materials, personal hygiene products and household goods, as well as medical and hygienic dressings, plasters and wound healing coatings as materials absorbing water and solutions, as well as water-releasing materials, nutrient, aromatic, biologically active and medicinal substances. Method comprises producing a biopolymer hydrogel, comprising preparing an aqueous solution of a water-soluble cellulose derivative and a polycarboxylic acid as a cross-linking agent, removal of water from the prepared solution and thermal treatment of the dehydrated composition at temperature of up to 150 °C, which initiates cross-linking of macromolecules of cellulose derivative, characterized by that solution containing 1.0–5.0 wt. % of a cellulose derivative selected from a series comprising hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxybutyl cellulose, methylhydroxyethyl cellulose, ethylhydroxyethyl cellulose, methylhydroxypropyl cellulose and carboxymethyl cellulose, and 0.5–3.0 wt. % of polycarboxylic acid represented by citric, oxalic or butane-tetracarboxylic acid. Water is removed from solution prior to cross-linking by sublimation drying with formation of dehydrated composition in the form of airgel. Thermal treatment of obtained airgel is carried out at temperature from 50 to 150 °C for 1–36 hours with its subsequent conversion into biopolymer hydrogel by impregnation with water or aqueous solution using immersion.

EFFECT: technical result is increased mechanical strength and elasticity of obtained biopolymer hydrogel, higher stability thereof during deformation while simultaneously providing the ability to rapidly absorb and retain a large volume of moisture and maintain high consumer properties due to formation of base in form of highly porous macromolecular structure, capable of withstanding large deformations.

1 cl, 9 ex, 7 dwg