From the Maya civilisation to Columbus and from Priestley to Goodyear, rubber has a rich history. The usefulness of the milky sap was discovered by chance. Below, we outline the history of rubber, from the discovery of natural rubber to the development of synthetic alternatives.
Before embarking on this journey of discovery, it makes sense to first address where rubber actually comes from. Natural rubber is derived from the Brazilian rubber tree, Hevea brasiliensis. These slender trees can grow up to 30 metres tall and thrive in the Amazon region. By making an incision in the cambium – a deeper layer of the bark – the latex vessels are cut, and the milky sap begins to flow. Small cups placed beneath each cut collect this sap, approximately 33% of which consists of rubber.
FROM TREE SAP TO RUBBER
Several steps are required to extract usable rubber from the tapped sap. The process begins with filtering and diluting the latex with water. The mixture is then treated with acid, causing the rubber particles to coagulate. These particles are rolled into thin sheets using a roller mill. After rolling, the rubber still contains too many proteins, which can lead to rotting. To remove these, the sheets are smoked in a special smoking chamber. The resulting ‘smoked sheets’ are then stacked into bales and transported to rubber mixing mills. What a process!
WHO DISCOVERED RUBBER?
Christopher Columbus was the first European to encounter rubber during his second voyage to Central America in 1493. However, the true discoverers were the Maya, who had long before tapped the milky sap from Brazilian rubber trees. By mixing it with other plant extracts, they created rubber, which they used to make items such as balls and toys. The major breakthrough came in 1770, when chemist Joseph Priestley accidentally discovered that rubber could erase pencil marks. This gave rise to the name ‘rubber,’ derived from the phrase ‘to rub out.’
GOODYEAR’S DISCOVERY: RUBBER, CARBON BLACK & SULPHUR
In 1839, inventor Charles Goodyear discovered that adding a small percentage of sulphur greatly improved the properties of rubber. By accident, a mixture of rubber and sulphur ended up on his stove – a serendipitous event that changed everything. Heating rubber in this way, a process now known as vulcanisation, allowed it to remain elastic while becoming stronger and non-sticky. It was later found that adding carbon black to vulcanised rubber made it even stronger. Following Goodyear’s discovery, rubber trees were planted on a large scale worldwide, particularly in India, Ceylon and Indonesia, ensuring a global supply of rubber. In June 1844, Charles Goodyear patented his groundbreaking discovery, securing his place in the history of rubber.
PURE NECESSITY: THE BIRTH OF SYNTHETIC RUBBER
By the late 19th century, the rapid growth of the automotive industry made a synthetic alternative to natural rubber increasingly appealing. Petroleum proved to be a promising solution.
However, it was not until World War II that synthetic rubber production truly took off – driven by necessity. Natural rubber was extensively used in military vehicles and aircraft. A thick layer of natural rubber was applied around the planes’ fuel tanks. If a wing was pierced during combat, the kerosene would interact with the natural rubber, causing it to swell. This swelling partially sealed the hole, giving pilots a better chance of returning home. Ironically, the poor resistance of natural rubber to oil, petrol and kerosene turned out to be a blessing in disguise.
During the war, the Allies faced a critical shortage of natural rubber. Germany exacerbated the situation by torpedoing cargo ships with submarines to cut off supplies. Out of necessity, an alternative was sought, leading to the development of SBR. By the 1970s, synthetic rubber had overtaken natural rubber as the preferred material. Today, numerous types of synthetic rubber have been developed to meet various industrial needs
Source : https://www.risrubber.com/