[a], Turaev Khayit

Synthesis and Characterization Of Superabsorbent Hydrogel Based On Starch-Sodium Section A-Research paper
Carboxymethylcellulose Hybrid
SYNTHESIS AND CHARACTERIZATION OF SUPERABSORBENT HYDROGEL BASED ON STARCH-SODIUM CARBOXYMETHYLCELLULOSE HYBRID


Kholnazarov Bakhodir ^[a], Turaev Khayit.^[a]*, Abdiev Bakhodir.^[a], Shukurov Dilmurod^[a], Kasimov Sherzod^[a], Normurodov Bakhtiyor^[a].

[a]. Termez State University, Termez, Uzbekistan

Email: [e-mail]


Annotasiya. In this work, environmentally friendly, highly swellable and biodegradable hydrogels based on a hybrid of starch and sodium carboxymethyl cellulose have been synthesized. As a result of introducing into the polymer chain and matrix of highly swelling hydrogels a hybrid of polysaccharides rich in hydrophilic groups and minerals - urea and bentonite, it has been proved that the water absorption of hydrogels increases by 25%, the water retention time increases by 20%, and the water consumption decreases by 25%. Also, during the synthesis of hydrogels with the addition of sodium bicarbonate, it was found that there are many large pores in hydrogels, and water and minerals dissolved in water can freely move through these pores. The swelling of hydrogels in solutions of salts of different concentrations with monovalent (NaCl), divalent (CaCl₂), and trivalent (AlCl₃) ions in solution was determined. The properties of the obtained hydrogels were also studied using the results of infrared (IR), scanning electron microscopy (SEM), and differential thermal analysis (DTA).
Keywords: Starch-carboxymethylcellulose, urea, montmorillonite, binding reagent, initiator, high swelling hydrogel.
INTRODUCTION
Cellulose and starch are the most common renewable materials in the world. Since cellulose and starch are environmentally friendly polysaccharides, highly effective hydrogels can be obtained from them. Changes in the structure of cellulose occur due to a decrease in the number of strong hydrogen bonds between hydroxyl groups, and cellulose derivatives become water-soluble. To obtain cellulose derivatives, hydroxyalkyl, alkyl and carboxymethyl functional groups are mainly used. [2,3].
In particular, carboxymethyl cellulose, which is a derivative of cellulose, is widely used in many fields. Using various methods, hydrogels with the participation of carboxymethylcellulose and binders have been synthesized. Binders such as epichlorohydrin, polyacrylic acids and N,N'-methylenebisacrylamide (MBA) are widely used in the synthesis of hydrogels. Hydrogels can also be made from carboxymethylcellulose using high energy radiation (electron radiation and gamma radiation).
These methods are not widely used because they require expensive technologies and have side effects on human health. The advantage of using binders in the synthesis of hydrogels is that they increase the degree of interrelation of the monomers. Also, binding reagents improve all the physicochemical properties of hydrogels - molecular weight, chemical structure and swelling. Starch is a very cheap and renewable polysaccharide, and as a result of its copolymerization with synthetic monomers, semi-synthetic hydrogels have been obtained. Starch is converted to gelatin before copolymerization [8, 9].
The initiator forms active centers and monomers are crosslinked through these active centers. The properties of starch-based hydrogels are affected by the ratio of amylopectin and amylose, which are part of the starch. [10].
Chemically crosslinked hydrogels are synthesized using the following reactions: 1) radical polymerization, 2) polyaddition and polycondensation, 3) radiation polymerization [46].