## 1 Introduction  
Recently, the demand for health care and sanitary textile products increased. These products are required for a hygienic, clean, and comfortable life due to the effects of COVID-19, as well as for promoting better health conditions and preventing problems caused by environmental pollution, such as with fine dust. Interest in preventive measures such as the use of masks, personal hygiene products, and disposable hygiene products is thus increasing. Currently, instead of producing sanitary products using non-woven fabrics, material studies are actively underway on the use of superabsorbent materials that can contain a large amount of water, without releasing absorbed water even under pressure. A typical scaffold form of a superabsorbent material is a hydrogel sponge. Hydrogels have a three-dimensional cross-connecting network structure in which the hydrophilic polymer is not dissolved in solvents and may contain a large amount of water or liquid (up to 1000 times or more of the weight of the polymer) [1; 2; 3]. Commercially widely used superabsorbent sponges are polymerized by adding polymerization initiators and crosslinking agents based on polyvinyl chloride (PVC), acrylic acid extracted from petroleum, and acrylamide. Currently, there are developments on superabsorbent sponges, but most of them are used as heavy metal adsorbents, soil moisture control agents for agriculture or horticulture, food packaging materials, and construction materials. However, its application to medical materials (diapers for infants and adults, sanitary napkins for women) and disposable sanitary products is low due to concerns about toxicity and environmental pollution [4; 5]. Therefore, the most important purpose of this study was to develop new ultra-highly absorbent medical materials using natural polymers with non-toxicity, biocompatibility,biodegradability, wide specific surface area, and abundant reactivity. Natural polymers, including plant-derived, animal-derived, and microbial-producing polymers, are composed of polysaccharides such as carbohydrates, proteins, and cellulose, and thus have biocompatibility and biodegradability characteristics. Examples of natural polymers include alginate (Alg), dextran (Dex), and carboxymethyl cellulose (CMC). Alginate is widely used to manufacture various types of superabsorbent scaffolds because it can be made into a product with excellent functions owing to its copolymer structure in which a mannuronic acid (M) block, gluuronic acid (G) block, and intermediate M/G block are linked by 1,4 glycosides. Since there is a carboxyl group (COOH-) in the alginate molecule, it is acidic and generally has a hydrogel formulation by ionic bonding with sodium salt (Na+) to form an egg model. Alginate in the form of its sodium salt may be developed into various types of hydrogels, capsules, or sponges through cross-linking with metal ions (Ca\({}^{2+}\), Ba\({}^{2+}\)). In particular, alginate is a water-soluble natural polymer polysaccharide with a negative charge and exhibits excellent antibacterial effects upon ionic bonding, with biodegradability, high water content, and non-toxicity [6, 7]. Dextran is highly water soluble and biocompatible, and is widely applied in biomedical medicine. Dextran is a complex and high molecular weight polysaccharide composed of glucose molecules made by bacterial decomposition of sugar cane candy, and the main chain is composed of \(\alpha\) (1\(\rightarrow\)6) glycosidic bonds between glucose monomers. The branched portion is connected by \(\alpha\) (1\(\rightarrow\)4), \(\alpha\) (1\(\rightarrow\)2) or \(\alpha\) (1\(\rightarrow\)3) glycosidic bonds. This characteristic branching distinguishes dextran and dextrin, and physicochemical properties appear differently, depending on the number of branched links and glucopyranosyl residues. Owing to these properties, dextran is widely used for hydrogel formulations and drug delivery systems.