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Amazon rubber cycle

Historical period of Brazil (1879 to 1912)

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Through Natural rubber, Amazon basin and Pará

Centered in the Amazon Basin, the boom resulted in a large expansion of colonization in the area, attracting immigrant workers and causing cultural and social transformations. Crimes against humanity were committed against local indigenous societies, including slavery, rape, torture. The thorough destruction of multiple indigenous cultures has been described as amounting to genocide.

It encouraged the growth of cities such as Manaus and Belém, capitals within the respective Brazilian states of Amazonas and Pará, among many other cities throughout the region like Itacoatiara, Rio Branco, Eirunepé, Marabá, Cruzeiro do Sul and Altamira; as well as the expansion of Iquitos in Peru, Cobija in Bolivia and Leticia in Colombia. The first rubber boom and genocides occurred largely between 1879 and 1912. There was heightened rubber production and associated activities again from 1942 to 1945 during the Second World War.

Background

Natural rubber is an elastomer, also known as tree gum, India rubber, and caoutchouc, which comes from the rubber tree in tropical regions. The South American natives first discovered rubber; sometime dating back to 1600 BC. The indigenous people of the Amazon rainforest developed ways to extract rubber from the rubber tree (Hevea brasiliensis), a member of the family Euphorbiaceae. Christopher Columbus was one of the first Europeans to bring news of this odd substance back to Europe, but he was not the only one to report it. Around 1736, a French astronomer recalled how Amerindians used rubber to waterproof shoes and cloaks. He brought several samples of rubber back to France. Rubber was used as an eraser by the British scientist Joseph Priestley, with "rubber" entering English parlance as a substitute for the term "eraser".

A white liquid called latex is extracted from the stem of the rubber tree, and contains rubber particles dispersed in an aqueous serum. The rubber, which constitutes about 35% of the latex, is chemically cis-1,4-polyisoprene ((C5H8)n). Latex is practically a neutral substance, with a pH of 7.0 to 7.2 (similar to pure water). However, when it is exposed to the air for 12 — 24 hours, its pH falls and it spontaneously coagulates to form a solid mass of rubber. Rubber produced in this fashion has disadvantages. For example, exposure to air causes it to mix with various materials, which is perceptible and can cause rot, as well as a temperature-dependent stickiness.

It was not until the 1800s that practical uses of rubber were developed and the demand for rubber began. In 1803 rubber factory open in Paris, France which made rubber garters for women. However, the material still had disadvantages: at room temperature, it was sticky. At higher temperatures, the rubber became softer and stickier as well as odorous, while at lower temperatures it became hard and rigid. In 1839, Charles Goodyear discovered a process of vulcanization, and the industrial demand for rubber subsequently became greater. Goodyear's vulcanization method involved mixing rubber with sulphur at high temperatures, resulting in a product that was "radically metamorphosized and could stand extreme extremes of heat or cold without melting or cracking."

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