How does latex from the Hevea brasiliensis tree become natural rubber?

Natural rubber is produced from the latex of the Hevea brasiliensis tree, which is a milky suspension containing approximately 30 percent polyisoprene.1

To extract the rubber, the tree is tapped by scoring the bark, allowing the latex to flow into collection cups. Once collected, the rubber is recovered from the emulsion through a process of coagulation, typically using formic acid. This creates crumbs that are washed, dried, and compacted into blocks for shipping. Alternatively, the coagulum may be pressed into thin sheets and dried over a smoky wood fire, which provides protection against mold.1

While this process yields raw natural rubber, its physical properties—such as tensile strength and temperature resistance—are further improved through vulcanization. This chemical process involves heating the rubber with sulfur, which creates cross-links between the long-chain molecules. Modern production often includes additives like carbon black or zinc oxide to enhance the material's durability and performance.2