A recent study published in Green Chemistry demonstrates that polysaccharide–electrolyte composite coatings exhibit excellent performance. Cardboard incorporating nanostructured fibrous particles of carboxymethyl cellulose and chitosan exhibits strong oil‑and‑water barrier properties. This coating not only resists toluene, n‑heptane, and saline solutions but also enhances mechanical strength in both dry and humid environments, while improving its resistance to water vapor transmission.
　　Researchers at Pennsylvania State University have developed an inexpensive biomaterial that can be used in packaging and as a renewable barrier coating to replace plastic packaging. The researchers have also identified numerous other applications for this material, and they predict that its adoption will significantly reduce pollution.
　　The fully biodegradable polysaccharide–electrolyte composite material is composed of nearly equal parts of treated cellulose pulp derived from wood, cotton, chitosan, and other sources, along with chitosan. Chitosan is derived from chitin, the primary constituent of the exoskeletons of arthropods and crustaceans; chitin, in turn, is predominantly obtained from lobster and crab shells, as well as the residual shells left over after people consume shrimp.
　　“This material is surprisingly robust; its insoluble adhesive properties make it useful for product packaging and other applications, such as the development of higher‑performing, entirely natural wood‑fiber composites—and it could even be used in flooring,” said Jeffrey Catchmark, professor of agricultural and biological engineering and principal investigator at Penn State’s College of Agricultural Sciences. He added that these eco‑friendly barrier coatings have a wide range of uses, from waterproof paper to coatings for ceiling tiles and wall panels, to food‑grade coatings designed to extend shelf life.