According to the Xinhua news agency, San Francisco, San Francisco, December(reporter Ma Dan)Researchers have announced that they have invented a new process for making hydrogels from natural materials. The prepared hydrogels are cheap, safe and flexible, and can be used in food processing and fire extinguishing.

　　The research is published in the Journal of proceedings of the National Academy of Sciences.Researchers at the Stanford University say the new hydrogels they have developed contain two cheap and rich basic materials, one is cellulose polymers taken from natural materials such as wood and crop straw, and the other is colloidal silica nanoparticles from sand.A stable hydrogel can be obtained by mixing two kinds of materials.

　　Researchers believe that this simple and cheap process is expected to overcome the current high cost constraints, making it possible to produce hydrogels in industrial scale. With the advantages of strong flexibility, non-toxic and environmental protection, the new hydrogel materials have wide application prospects. The researchers introduced the new hydrogel used to clean the winery pipes and spread the flame retardants.

　　Eric Appel, an assistant professor of materials science at the Stanford University, said that a brewery will lose 2% of its products in the process of production, mostly in transit. They worked with a wine factory in California, trying to use a special formula of hydrogel instead of water to wash the residual grape juice in the pipeline. Since hydrogel is not mixed with grape juice, it hardly causes product loss. The hydrogel made of food grade materials such as cellulose and colloidal silica has no effect on the odour and taste of grape juice.

　　There are frequent wildfires in North America, and lots of flame retardants are needed to extinguish them. Many flame retardants contain chemical constituents that contaminate groundwater, and are also easily washed away by subsequent sprayed water, which will affect the extinguishing effect. The researchers used a mixture of flame retardants and new hydrogels in the experiment, and found that the mixture was attached to the burning substance longer than the ordinary flame retardant, and could protect the flame retardant from the water that was sprayed by the later. Compared to ordinary flame retardants, the flame retardants in mixed hydrogels can also be released from higher air, drift and volatilize less, and do not pollute the ground water, Appel said.

　　The research team is testing the new hydrogel materials in a large scale to expand its commercial application prospects. They are also developing new hydrogel formulations, enabling hydrogel materials to be used in cosmetic additives, lubricants in oil drilling operations, etc.