Researchers in Japan have now made a new paper-based material that could be an ideal replacement for those single-use plastics. The millimeter-thick paperboard reported in the journal Science Advances behaves like plastic, but only when needed. It is strong, transparent and shapeable, and it can hold boiling water, but it degrades within a year after settling on the ocean floor.
They made a thick cellulose hydrogel by dissolving cellulose in an aqueous lithium bromide solution. Drying the hydrogel gave clear cellulose sheets that were a millimeter-thick. The researchers could shape the sheets to make cups or straws.
A cup made from the transparent material could hold just-boiled water for over 3 hours with no leakage. When the researchers coated the cup with a plant-derived fatty acid salt, it became completely waterproof.