Cellophane

Its low permeability to air, oils, greases, bacteria, and liquid water makes it useful for food packaging.

Cellulose from wood, cotton, hemp, or other sources is dissolved in alkali and carbon disulfide to make a solution called viscose, which is then extruded through a slit into a bath of dilute sulfuric acid and sodium sulfate to reconvert the viscose into cellulose.

Cellophane was invented by Swiss chemist Jacques E. Brandenberger while employed by Blanchisserie et Teinturerie de Thaon.

[6] In 1900, inspired by seeing wine spill on a restaurant's tablecloth, he decided to create a cloth that could repel liquids rather than absorb them.

By 1912 he had constructed a machine to manufacture the film, which he had named Cellophane, from the words cellulose and diaphane ("transparent").

DuPont hired chemist William Hale Charch (1898–1958), who spent three years developing a nitrocellulose lacquer that, when applied to Cellophane, made it moisture proof.

Cellophane also worked to consumers' disadvantage when manufacturers learned to manipulate the appearance of a product by controlling oxygen and moisture levels to prevent discolouration of food.

The polluting effects of carbon disulfide and other by-products of the process used to make viscose may have also contributed[citation needed] to its falling behind lower cost petrochemical-based films such as biaxially-oriented polyethylene terephthalate (BoPET) and biaxially oriented polypropylene (BOPP) in the 1980s and 1990s.

[1] When placed between two plane polarizing filters, cellophane produces prismatic colours due to its birefringent nature.

Viscose factories vary widely in the amount of CS2 they expose their workers to, and most give no information about their quantitative safety limits or how well they keep to them.