Natural rubber - the other wonderful (but less tasty) tree sap!

Britney Jones
23 January 2012

Above: Image © styf22, iStockphoto.com

Natural rubber has many impressive qualities—it can bounce, be put under extreme pressure, and even be used to erase (or “rub out”) pencil marks on paper. But of all its fascinating abilities, natural rubber is best known for its elastomeric properties; it is easily stretched and can snap back into its original shape when released.

Created using the sap (latex) secreted from the Haveabrasilliensis (or ‘rubber tree’) rubber can be used to create an enormous range of products from surgical gloves to pneumatic tires, to party balloons to golf balls.

In order to harvest rubber, a thin layer of bark is cut and a spout is hammered into the tree.Then, the latex is allowed to drip into a container for about three hours. Finally, the latex coagulates, or solidifies, and the cut in the tree’s bark seals up (like a blood clot seals up a wound).

Did You Know? Latex is a complex mixture of alkaloids, gums, oils, resins, sugars, starches, and tannins. When exposed to air, it congeals to form a solid mass.

Once the latex has been collected, ammonia is added to stop the coagulation process.This causes the sap to split into two-phases which are then separated by centrifugation and sold as high and low ammonia concentrates.

Did You Know? Centrifugation uses gravity to separate materials of different densities by spinning them at incredibly high speeds.

These concentrates are further processed by adding preservatives, antioxidants, and accelerators and then transformed into products. The majority of this rubber is used to create extruded rubber products, vehicle tires, and injected molded goods while a smaller portion is used for dipped products, such as condoms, balloons, and rubber gloves.

Did You Know? Dipped products are the most common cause of latex allergies.

Learn More!

Latex:How Products are Made

International Rubber Study Group

RubberFAQs

References:

Woods, J.A., Lambert, S., Platts-Mills, T.A.E., Drake, D.B., and R.F. Edlich. 1997.Natural rubber latex allergy: Spectrum, diagnostic approach, and therapy. J. Emergency Medicine. 15: 71-85. Information on Rubber - UNCTAD

Article first published May 18, 2011

Britney Jones

Britney earned her undergraduate degree at the University of Calgary, majoring in biological sciences and minoring in psychology. She then went on to receive a Master’s degree in Biomedical Technology, where she developed a keen interest in health advocacy research. Britney spent two years as a member of the Clinical Research team at the Tom Baker Cancer Centre. Currently, she is in her third year of medical school. 


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