So Unfamiliar Rubber or What is Rubber
We are so accustomed to goods made of rubber that often undervalue its meaning in our everyday life. It's difficult to imagine how would have changed the world if there were no rubber any more. It is used in the production of band-aids, surgical gloves, tyres, toys, sporting goods, etc.
But what's this? It's a yellowish, elastic, sticky material obtained from a milky liquid called "latex" or derived from natural gas and petroleum. So there're two types of the material - natural and synthetic.
Natural rubber (or caoutchouc) is prepared from the sap of various tropical and subtropical plants. Latex can be found in over 400 different trees and plants but the lion's share of it (approx. 96%) is extracted from the rubber tree (also called Hevea brasiliensis). It is more cost-effective than other plants, and grows mostly in South America, West Africa, and South Asia.
The trees take around five years to grow to the point that they can start to produce latex. Their economic life lasts about 25-30 years, and their sap contains 67 % water and only about 33% caoutchouc. Hevea brasiliensis is tapped once every two days, yielding roughly 1.7 ounce of solid rubber each time.
Caoutchouc continues to take a significant position in the market today. It is still used in medicine all over the world due to its superb resilience over synthetic rubber and its high resistance to tear. Caoutchouc is also valuable for tyres used on trucks, buses, racing cars, and airplanes because of the excellent resistance to heat buildup.
It's surprising how long this material have been around. It is known that ancient Mayas and Aztecs played crude rubber balls at least 900 years ago. Caoutchouc was also used in the painful process of stockings creation - rubber paste was applied to feet and held over fire.
Charles-Marie de La Condamine was first who scientifically described caoutchouc in 1735. But it got its name only in 1770 when English scientist Joseph Priestly found it was useful for rubbing pencil marks. Waterproof cloaks, known as "mackintoshes," were invented in 1823 and owe their existence to Charles Macintosh. And the problem with caoutchouc (it hardened with cold and softened with heat) was solved in 1839 by Charles Goodyear who invented vulcanization and made the modern rubber industry possible.
Nowadays, not all latex is natural - a considerable amount of it is made chemically. Such latex is called synthetic. It is manufactured at a factory where two by-products of petroleum refining are mixed, vulcanized, and dried to give rubber in the final result. Its chemical formula varies and can be adapted to different applications.
Production of synthetic latex developed in the USA during World War II. At that time supplies of natural latex were cut off by Japan. Since then, the use of synthetic rubber has overtaken caoutchouc in leaps and bounds.
World rubber consumption is about 20 million tons per year. That's why it is very important to reprocess and recycle products made of it, since these processes use less energy than producing new material.