The Evolution of Rubber: From Ancient Discovery to Modern Applications

History and Culture

The Evolution of Rubber: From Ancient Discovery to Modern Applications

Written by Chittaranjan Panda · 7 min read >
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Rubber, an adaptable and essential substance in our daily existence, has a captivating history that extends across many centuries. From its modest beginnings as an intriguing novelty to its extensive utilization in various industries today, the creation and development of rubber have significantly influenced our lifestyles and professions. Within this blog, we will take a historical voyage, following the remarkable metamorphosis of rubber, starting from its initial identification to its numerous contemporary uses. Come along as we delve into the past, ingenuity, and profound influence of rubber on our society.

Rubber First Use

In Brazil, deep within the Amazon River region, there existed an expansive forest teeming with diverse flora and fauna, much like contemporary forests. Within this natural habitat, various birds, animals, insects, and beetles coexisted. Nature, in its wisdom, had devised protection mechanisms for these trees. Some trees were shielded from leaf-eating insects by natural predators that consumed these pests. Meanwhile, certain trees had developed defensive adaptations like thorny or bristly bark to deter potential threats.

Within the forests where rubber trees thrived, a particular wood-boring beetle posed a threat by burrowing into these trees. However, the rubber tree had a natural defense mechanism in the form of poisonous juice. When the beetle penetrated the tree, this toxic substance would swiftly eliminate the intruder. Subsequently, the hole left by the beetle would be sealed by the oozing juice, allowing the tree to continue its growth unharmed.

In those times, the indigenous people residing near these forests, a blend of Indigenous and African descent, came across some of this sticky juice adhering to the tree’s surface. They harvested and rolled it into a ball, which they used for playing games. The first documented reference to this material was made by Herrera in his account of Columbus’s second voyage. He mentioned a ball used by Indigenous people, crafted from the gum of a tree that was lighter and had superior bouncing properties compared to the renowned balls of Castile.

The method by which they collect this rubber is quite intriguing. Initially, when it oozes from the tree, it appears as a milky liquid. The Indigenous people of South America quickly realized that the Europeans were eager to exchange beads and various small ornaments in return for portions of this rubber. Consequently, they became actively engaged in the gathering and trade of this valuable resource.

Rubber Camp

In this region, the rubber harvest typically kicks off with the onset of the Amazon’s descent, which typically occurs around the beginning of August. As this date approaches, groups of Indigenous people leave their rudimentary dwellings and venture deep into the forest lowlands, often traveling hundreds of miles. Once they’ve reached locations close to rubber trees, they establish their camps, marking the commencement of the rubber harvesting process. This endeavor typically spans about six months, stretching from August through January or February.

The homes of rubber gatherers in this region are quite basic, consisting of roofs and floors with flimsy walls. These structures are elevated on stilts for several reasons, including to stay cool, protect against animals and insects, and prevent flooding during the wet season. The more elaborate and well-furnished residences of the estate superintendent, along with the storage buildings, are collectively referred to as the “seringal.”These buildings are typically clustered in strategic locations along the banks of the Amazon or its tributaries.

The climate in the South American rubber-producing areas is harsh and often deadly for white individuals. Even among the Indigenous population, the prevalence of fevers, poisonous insects, reptiles, and other hazards of the tropical forest results in a high mortality rate. Surprisingly, the production of South American rubber is constrained not by a scarcity of rubber trees but by a shortage of laborers.

As December arrives, so does the rainy season. The Amazon’s water levels begin to rise, leading to a halt in work. The superintendent and many laborers head downstream to Para and Manaus or relocate to higher ground villages. Nevertheless, some laborers typically remain in their huts, passing the time by dealing with the animals and insects seeking refuge from the rising waters. They have limited food supplies and minimal communication with the outside world throughout this season.

As the rainy season draws to a close, typically in early May, the laborers return to their work. During the rainy season, the fast-growing vegetation has overgrown the “estradas,” which are paths connecting one Hevea tree to another and circling back to the camp. These estradas must be cleared of vegetation, and sometimes new ones need to be established. Each estrada typically links around one hundred scattered Hevea trees.

Once they’ve settled back into their camp, the Indigenous workers resume their repetitive routine, which continues day after day as long as the rubber trees continue to yield their valuable sap. When a “seringuero” sets out for work, they equip themselves with a tomahawk-like axe that has a handle of approximately thirty inches in length. This tool is known as a “macheadino.”

Rubber Gathered by the Natives

The process of tapping rubber trees bears some resemblance to tapping maple syrup trees. However, in the case of rubber trees, the valuable juice is located between the outer bark and the wood. To extract this juice, the workers make a cut in the tree through the bark, going almost down to the wood. Then, they attach a small cup to the tree using a piece of soft clay to press the cup against the cut, allowing the juice to flow into it. It’s common to find anywhere from ten to thirty cups on a single tree, with an average yield of about ten pounds of rubber per tree annually.

Approximately two hours after the initial tapping, the flow of juice completely stops, necessitating the need to tap the tree again to obtain a fresh supply.The layer of rubber that forms on the inside of the cup and any residual bits of rubber left on the tree are collected and sold as a coarser grade known as “Para.”

In addition to their macheadino and numerous small tin cups, the rubber gatherer also carries a larger container for collecting the liquid and transporting it back to the camp. A single individual can tap as many as 100 trees in one morning, and then revisit the same trees in the afternoon or the following morning to collect the sap that slowly drips from the cuts made in the trees.

During these journeys, harvesters often cover extensive distances along paths that are nearly concealed by the dense undergrowth of the jungle, making them almost invisible to untrained eyes. In order to protect themselves against potential threats from wild animals, reptiles, and potentially hostile Indigenous groups, rubber gatherers typically carry rifles on such expeditions.

Rubber Smoke

Once the rubber sap has been collected in this manner, the Indigenous gatherer proceeds to build a fire. Over this fire, they position a cover that resembles a large bottle with its bottom removed. The fire is typically fueled by oily nuts sourced from the forest, and the dense smoke rises through what would essentially be the neck of the bottle-shaped cover.

The process of turning the milky rubber sap into a usable form involves a specific technique. The rubber gatherer employs a stick, somewhat resembling a wooden shovel used at the seashore. They dip this stick or paddle into the milky juice in the bowl and then vigorously rotate the stick within the thick smoke produced by the fire. This action causes the juice to bake onto the paddle. They repeat this process multiple times, adding more juice each time, until there is approximately five to six pounds of rubber baked onto the paddle. Subsequently, they cut this mass off using a wet knife, forming what is known as a rubber “biscuit.” The process then repeats for the next five to six pounds of rubber.

As demand for these rubber “biscuits” increased, the natives modified their approach. Instead of using a paddle, they set up two short fence-like structures about six feet apart, parallel to each other, with a smoky fire in between. They acquired a long pole, stretched it across these two rails, and poured a small quantity of the rubber sap onto the pole where it came into contact with the smoke. They then rolled the pole around until the sap baked onto it, adding more as needed. Instead of forming small “biscuits,” this method produced large balls of rubber. To remove the rubber from the pole, they would gently tap one end of the pole on the ground until the “biscuit” slid off. This is the way crude rubber initially entered our market and continues to be processed today.

Discovery of Vulcanization

Until this point, these rubber “biscuits” had a characteristic behavior: they would turn soft and sticky when exposed to heat and become hard as a stone when subjected to cold temperatures.

An American named Charles Goodyear became intrigued by the various ways in which the natives of rubber-producing regions utilized the milky rubber juice for their own needs. One of their applications involved using it to waterproof their cloaks. Goodyear pondered how this natural substance could be employed to make clothing water-resistant without becoming sticky in the heat or stiff in the cold. He dedicated a significant portion of his time to solving this challenge, but like many pioneering inventors, he encountered numerous setbacks. His repeated failures led to his friends abandoning him, and he even found himself imprisoned for failing to repay his debts. Nevertheless, Goodyear persisted in his quest, and it was ultimately a fortuitous accident that paved the way for the discovery of vulcanization, the process he had been diligently seeking.

In the spring of 1839, at Woburn, Massachusetts, Charles Goodyear found himself in the company of his brother and several others, near a scorching-hot stove. He held in his hand a mixture he had created, combining sulphur and gum, passionately explaining his creation in his characteristic fervent manner. However, his companions paid little attention, as they were accustomed to his enthusiastic speeches. In the heat of the moment during his explanation, he made a sudden gesture, accidentally bringing the mass into contact with the blazing-hot stove, hot enough to instantly melt India rubber.

Upon examining the compound moments later, Goodyear was astounded to find that it hadn’t melted at all. Instead, it had charred, similar to how leather chars, but there was no sign of it becoming sticky or liquefying. The sheer novelty of this result left him utterly amazed, as it was entirely unprecedented—India-rubber not melting upon contact with red-hot iron! His astonishment was akin to that of Columbus

Until that point in time, all rubber was commonly referred to as Para rubber, named after the town of Para in Brazil, which served as the primary shipping point for rubber exports. The mature rubber tree is quite substantial, typically reaching heights of sixty feet or more, with a trunk circumference of around eight feet. It boasts pale green-colored flowers, and its fruit takes the form of capsules containing three small brown seeds with patches of black. These seeds have a very short lifespan, so careful handling and packing are essential if they are to be used for planting in another location. The safest method is to place them loosely in a container filled with dry soil or charcoal.

Rubber Growing Spread to Other Places

In the 1870s, an English botanist named Wickham undertook a daring venture, smuggling numerous Hevea seeds out of Brazil. These seeds were later found to thrive in the Eastern tropics, and today, rubber plantations in places like Ceylon, Borneo, the Malay Peninsula, and nearby regions contribute to producing over half of the world’s crude rubber supply. The favorable climate in these areas, combined with careful cultivation, leads to improved growth and better yields compared to rubber trees in the wild.

On these plantations, rubber trees are cultivated much like other crops. Weed control is a priority, and significant attention is given to the care of young trees. To enrich the soil, low-growing plants such as passion flowers and other nitrogen-absorbing species are planted around the young rubber trees. This practice helps maintain soil quality since removing all weeds can lead to soil compaction and dryness.

On these plantations, rubber trees are cultivated much like other crops. Weed control is a priority, and significant attention is given to the care of young trees. To enrich the soil, low-growing plants such as passion flowers and other nitrogen-absorbing species are planted around the young rubber trees. This practice helps maintain soil quality since removing all weeds can lead to soil compaction and dryness.

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Written by Chittaranjan Panda
Dr. Chittaranjan Panda is a distinguished medical professional with a passion for spreading knowledge and empowering individuals to make informed health and wellness decisions. With a background in Pathology, Dr. Chittaranjan Panda has dedicated his career to unraveling the complexities of the human body and translating medical jargon into easily understandable concepts for the general public. Profile
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