In recent years, there has been increasing interest in biodegradable materials that can be decomposed in the natural environment using biomass materials in order to solve environmental problems derived from plastics that remain in the environment.On the other hand, many biodegradable materials have weaknesses in strength and moldability, and there is a problem that the range of use is limited.

　In response to this problem, this research group focused on the agglutination behavior of substances that occur when water freezes.A gel is formed by mixing carboxymethyl cellulose (CMC) nanofibers, which is a type of cellulose nanofibers, with citric acid, but by "freezing" the CMC nanofibers, mixing them with a citric acid solution, and melting them, high strength and molding He said he found that he could produce a gel with sex.

　The reason for the high-strength gel is that the aggregates of CMC nanofibers formed around the ice crystals when the solution freezes react with citric acid as they are, forming a gel skeleton with a strong three-dimensional network structure. Conceivable.This "freeze-crosslinked cellulose nanofiber gel" has the world's highest level of strength that can withstand a compression load of 2 tons, and has shown high moldability that can be molded into various three-dimensional shapes.In addition, it has been found that it is likely to be useful as an adsorbent for recovering harmful substances from contaminated water.

　This result, which succeeded in developing a high-strength gel material using only naturally-derived materials such as "cellulose" obtained from wood, "citric acid" contained in lemons, and "water", remains in the environment. It is expected to be applied to various applications such as non-plastic substitute materials, environmental purification materials, and unprecedented regenerative medical materials.

Paper information:[ACS Applied Polymer Materials] Eco-friendly carboxymethyl cellulose nanofiber hydrogels prepared via freeze crosslinking and their applications