cellophane

cellophane thin, transparent sheet or tube of regenerated cellulose . Cellophane is used in packaging and as a membrane for dialysis . It is sometimes dyed and can be moisture-proofed by a thin coating of pyroxylin . There are several steps in the preparation of cellophane from raw cellulose. The cellulose is first treated with an alkali, e.g., sodium hydroxide, and mixed with carbon disulfide to form viscose (see viscose process ). The viscose is aged for several days and then forced through a straight or circular slit into a dilute acid solution. The dissolved cellulose precipitates, and this regenerated cellulose has a lower molecular weight and a less orderly structure than the cellulose from which it is formed.

Cellophane Trade name for the first of the transparent, non‐porous films, made from wood pulp (cellulose), patented in 1908 by the Swiss chemist Jacques‐Edwin Brandenburger; waterproof cellophane for food wrapping was developed by Du Pont in 1926. Still widely used for wrapping foods and other commodities.

cellophane Flexible, transparent film made of regenerated cellulose and used mostly as a wrapping material. It is made by dissolving wood pulp or other plant material in an alkali, to which carbon disulphide is added to form viscose. This is forced through a narrow slit into a dilute acid where it precipitates (separates as solid particles) as a film of cellulose. It is then dried and waterproofed.