Leonardo was years ahead of his contemporaries in many fields. In scientific research, he disregarded what had been found before and accepted only what he could observe and test for himself. In painting, he used new materials and produced some wonderful works, like the Mona Lisa and Last Supper. He was obsessed by nature and loved to draw animals, fishes and birds, chiefly because he was fascinated by their movement. And since he was also a skilled engineer, he thought a lot about adapting these movements to machines, and thus dreamed up the idea of aeroplanes and submarines.
Synthetic rubber is made of certain kinds of hydrocarbons.
Of these, butadiene is the most important. These hydrocarbons are obtained from coal, crude petroleum and alcohol. By the end of the Second World War, the combined production of synthetic rubber by USA and Germany alone was almost equal to that of natural rubber. Synthetic rubber is more oil resistant than natural rubber. In the international market, natural rubber is facing severe competition from synthetic rubber.