METHOD FOR OBTAINING POLYACRYLAMIDE HYDROGEL Russian patent published in 2021 - IPC C08F120/56 C08F2/10 C08F20/56 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for preparing a polyacrylamide hydrogel. This method involves mixing the polymerizable mixture containing methylenebisacrylamide and acrylamide at their molar ratio of 0.5:10, at a speed of 40-50 min^-1 until the acrylamide is completely dissolved. A polymerization initiator is added to the resulting solution: first, tetramethylenediamine in an amount of 0.2-0.6 wt.% of the total weight of the mixture, and then ammonium persulfate is added to the reaction mass in an amount of 0.01-0.08 wt.% by weight of acrylamide. The reaction mass is heated to 40-80°C and water is introduced into the formed hydrogel with stirring at a speed of 40-50 min^-1 in an amount of 10-40 wt. % by weight of the hydrogel. The reaction mass is stirred at the same speed until the formation of the hydrogel product begins. Further, an additional amount of water is gradually introduced in an amount providing 20-80% water content by weight of the hydrogel. The formed hydrogel in the form of lumps with a volume of 0.5-5.0 cm³ is pumped into the grinding device. The hydrogel is stirred at a speed of 1000-1500 min^-1 and the resulting 5-45% hydrogel suspension is pumped into a homogenizer, where it is forced through a mesh cartridge with a mesh size of 350-500 microns under pressure.

EFFECT: obtaining a suspension of hydrogel particles with a predetermined particle size distribution in the range from 10 to 900 microns and a predetermined concentration of hydrogel particles from 5 to 45%.

1 cl, 3 ex