Otis Shepard. Wrigley’s Double Mint Chewing Gum.Well, contrary to popular myth, it does not stay in your body being digested for seven years. But before you go gulping a mouthful down, you might want to know what does happen.

Todays chewing gums base is made of synthetic rubber and plastics. Synthetic butyl rubber is a concoction of long linking polymers of isoprene. When vulcanized, it goes into making for tires for your car. And is put on the inside of basketballs to stop them deflating; the unvulcanised form is what your yummy gum base contains.

Because long linking polymers have a dearth of chemical bonding sites where oxygen can attach and oxidise it, this non-biodegradeable structure is resistant to digestive acids and enzymes in our digestive sytem.

So when you swallow it, gum slowly moves through your system and then out, and goes on to gum up the sewage systems. The removal of chewing gum from uban areas has become a major concern of some cities, along with litter and grafitti. New products are now available for the removal of gum, including high power lasers, industrial-strength solvents and water-blasting machinery. There are also new biodegradable gums now in development that promise to be easily digestible and easier to clean up as well. Let’s hope they come soon.

P.S. Sorbitol, which can act as a laxative, is sometimes used for sweetener in sugar-free gum. That means some gum might actually help things move though your system faster if swallowed.

P.P.S. The invention of synthetic rubber is a fascinating story in its own right. Natural rubber was used in many products, mainly automobile and truck tires. It was harvested from wild rubber trees in the jungles of South America. The surge in demand for natural rubber brought about by the automobile in the beginning of the 20th Century caused a goldrush-like boom and bust in Brazil, centered on the city of Manaus.

From 1890 to 1920 the rubber boom brought decadent wealth to the former small settlement on the Amazon, where it was common to see rubber barons light cigars with 100 dollar bills and water their horses with buckets of French champagne. A great ornate Opera House was constructed in the middle of the jungle, and famous performers from around the world were brought in to entertain the wealthy.

The bust came with the development of rubber plantations in Ceylon (now Sri Lanka) Borneo and Malaysia. The cultivation of rubber plants outside of Brazil only happened because an Englishman Sir Henry Wickham surreptitiously collected rubber seeds from the wild trees of the Amazon jungles (importation of the trees was strictly controlled by Brazil). 70,000 seeds were shipped to Kew Gardens in London, out of which 2,300 successfully germinated.

This leads to the concentration of raw rubber production in SE Asian British colonies. This became a concern to the U.S during World War 2, when worldwide natural rubber supplies were constricted, since by mid-1942 the majority of the rubber-producing areas were under Japanese control. Chemists had first laboratory synthesized rubber in the ‘30s, but the costly process meant it was not a viable replacement for natural rubber yet.

Accordingly, the US government launched a major drive to develop industrial-scale synthetic rubber production. During the war, this program developed styrene butadiene synthetic rubber and funded plants to provide a critical alternate to natural rubber, used in tires for military vehicles during the war. These plants became the foundation of the post-war U.S. rubber industry.

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