Where does rubber come from?
(Lansing State Journal, September 1,1993)

Currently, most rubber is produced using petroleum.  However, more than one quarter of all rubber produced is derived from latex extracted from living trees.  The two sources produce different types of rubber with different properties.

Petroleum contains many different types of carbon containing molecules, which are the starting point for synthetic rubber production.  Some of crude petroleum can be processed into molecules called dienes.  Dienes can be reacted to form long chains, called polymers, which make up all synthetic rubbers.  The first synthetic rubber, made of styrene butadiene, is still the major form produced today.

Natural rubbers are made from elastic latexes.  Latex is a mixture of organic compounds produced by some plants in special cells called caticifers.  The composition of latex differs from plant to plant.  Most natural rubber comes from a single species of tree, Hevea brasiliensis.  Though native to South America, H. brasiliensis is planted in large plantations in southeast Asia.  Trees are tapped by removing thin strips of bark, which disrupts the laticifers.  The latex then flows down grooves cut in the tree and drips into collection cups.

During World War II, natural rubber supplies were largely cut off to the United States.  It was then the need for the commodity encouraged serious experimentation into producing synthetic rubber.  While synthetics still predominate, the greater resilience of natural rubber makes it desirable for many applications, such as the production of radial tires.

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