Rubber Series: From Rubber to Elastomer
As a schoolboy, the American Charles Goodyear (1800-1860) had already become fascinated by the strange properties of rubber. For years he tried to reduce the stickiness of the substance by mixing different substances with it, such as flour, salt, and carbon black. One day in 1839, a small mishap got him onto the right path. A small piece of rubber with sulfur added fell onto the hot burner of a stove. The resulting material was wonderfully elastic, a property that it didn’t lose at hot or cold temperatures. Therefore, by baking the rubber with sulfur, the viscous and plastic natural substance had become an elastic material that retained its shape. The reason Goodyear called this process of baking the rubber “vulcanization” is that heat and sulfur were the magic potions of the god Vulkan in the Greek mythology. 80 years later, the German Nobel laureate Hermann Staudinger recognized that this process was nothing other than “polymerization” – a reaction of the relatively small rubber molecules to form a large molecular bond. By Goodyear’s invention of the vulcanization many of the unpleasant caoutchouc characteristics had been taken away, so that a significant and steady growth of the rubber industry began.
The mention of the car tire in connection with the history of the rubber is in so far important that the tires brought a huge boost to the rubber industry. In 1845 Robert William Thompson invented the air-filled rubber tire. His invention, however, fell into oblivion. Although full-cushion tires emerged during the 60ies it took until 1888 before Dunlop invented the pneumatic tire again. From 1894 not only bicycles were equipped with the air-filled rubber tires but also cars. The development which began was so immense that by 1930 the percentage of tires on the rubber consumption rose up to 75%.