Exploring the Journey of Rubber, from Tree Sap to Everyday Material.
If you’ve ever made a mistake and used an eraser to wipe it away, you might be wondering just where this mysterious substance originally came from. From the tires on all our cars, to mattresses, to cookware…rubber is everywhere in our lives.
The discovery of rubber as a material is attributed to the indigenous cultures of Mesoamerica, particularly the ancient Olmec civilization. They were the first to observe the unique properties of rubber, obtained from the latex sap of various tree species, and create a usable rubber product.
Where the Name “Rubber” Comes from:
The name “rubber” is attributed to Joseph Priestley, and Englishman in the late 18th century who observed that rubber was very good at rubbing off pencil on paper materials.
The Main Rubber Tree Species:
The two primary rubber tree species are Hevea brasiliensis and Ficus elastica.
- Hevea brasiliensis, commonly known as the rubber tree or para rubber tree, is native to the Amazon rainforest in South America, particularly Brazil, and is widely cultivated in Southeast Asia.
- Ficus elastica, also known as the rubber fig or Indian rubber tree, is native to Southeast Asia, including regions like India, Indonesia, and Malaysia.
These natural habitats continue to be important sources of rubber today.
Harvesting Rubber (or Latex, more specifically):
So how do you get the rubber from the tree? Through a variety of techniques that are called “tapping techniques”. These techniques involve carefully extracting latex from rubber trees without causing harm or hindering their growth.
Skilled tappers will make incisions in the bark, allowing the white latex sap to flow into collection cups.
In today’s world, most rubber tapping techniques incorporate sustainable practices. These include rotation systems, where trees are tapped in cycles to allow for recovery periods, as well as implementing measures to prevent over-tapping and damage to the trees. Additionally, initiatives promoting responsible land management, reforestation, and community involvement aim to ensure the long-term sustainability of rubber production while minimizing its environmental impact.
After the rubber is extracted, it undergoes processing to remove impurities. These steps usually involve filtering, sometimes centrifuging…or even adding chemicals to stabilize the latex itself.
The Next Step is…Coagulation?
Coagulation is the process of turning the liquid latex into solid chunks (or sheets). Most of the time coagulation is achieved by adding substances that cause the latex particles to stick together and form clumps.
The clumped latex is then dried (either by air drying or using specialized machinery) to remove excess moisture and create solid raw rubber that can be further processed.
But raw rubber isn’t the endgame. If you want the finished substance that we use on everything from car tires to pencil erasers, you need vulcanization.
How Vulcanization of Rubber Works:
Because raw rubber is soft, sticky, and temperature-sensitive, it’s not suitable for most applications. Raw rubber undergoes vulcanization, which is a process that adds chemicals (like sulfur) to raw rubber, in addition to adding heat and pressure.
At the molecular level, vulcanization makes the rubber molecules bond together. What does that mean? It means the newly-vulcanized rubber is more heat-resistant, durable, and elastic.
Now it’s ready to be shaped and molded into the consumer (and industrial) products we think of when we think of rubber.
The Journey Continues.
That’s not the end of the story of rubber. There’s global rubber production hubs all around the world with industry initiatives to make rubber into a more sustainable material.
And there’s even synthetic rubber with its own unique development and production. And the applications of rubber haven’t been fully explored either. Industries continue to find new applications of rubber in technologies.