Pure gum rubber, also known as natural rubber, is the elastomer that started it all. Made out of the coagulated latex produced from the Para rubber tree Hevea brasiliensis, natural rubber has been used as far back as 1600 BCE. The ancient Mesoamerican civilizations like the Olmecs, the Aztecs, and the Mayans used it as a ball for sports, and incredibly enough, natural rubber is still used to make balls for sports. In addition to sporting purposes, natural rubber material was also used as a currency in their societies. The Olmecs were the earliest recorded users of natural or “live rubber.” After all, the name “Olmec” literally translates to “rubber people”. There are 5 mechanical properties of natural rubber that have transcended time.
As word spread about the resilient and flexible elastomer, the material started being commercially grown and processed. The European nations quickly realized that pure gum rubber was ideal for many of their tasks and products, such as erasing pencil marks and sealing cases of wine. The French, English, and Portuguese were the first to gain control of the production of natural rubber and it was not long before products using rubber flooded European markets. Natural rubber helped in the spread of industrialization because a lot of the products being made by the new factories, products that were in very high demand, were some kind of natural rubber material. Consequently, more and more uses for the rubber grew worldwide, including the use of rubber in waterproof shoes and coats, drum pads, and gaskets for factories.
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5 Mechanical Properties of Natural Rubber – Pure Gum Rubber
What exactly is it about this flexible elastomer that has made it one of the most valuable natural resources in history? Why has it endured since the discovery of the Americas and all the way up to today in the post-industrial world of the 21st century? Here are the five mechanical properties of natural rubber and reasons why its modern industrial counterpart pure gum rubber has remained popular to this day:
- Low compression set: An elastomer’s ability to rebound to its original thickness after being compressed is measured by compression set testing. The compression set test results indicate the percent of the material that did not rebound. Low percentages are good whereas high percentages are bad. Natural or “live rubber,” in contrast to other rubbers, has a very low lowest compression set. In fact, it has one of the lowest compression sets of any elastomer, synthetic or otherwise. Due to this trait the elastomer is commonly used as a gasket and seal.
- Great resilience and abrasion resistance: Resilience is an elastomer’s ability to rebound after temporary deformation. Abrasion resistance indicates an elastomer’s ability to resist constant contact and rubbing from an abrasive substance. Natural rubber excels in both abilities, making it an ideal material for dynamic gaskets and seals.
- High tensile strength and tear resistance: The calculation of tensile strength and tear resistance depends upon the specific hardness of the natural rubber material. Generally, this natural flexible elastomer has a high tensile strength, meaning it can be stretched significantly without snapping. It also has excellent tear resistance, which is the ability to remain intact when there is a rupture in the material.
- Good surface friction: Pure gum rubber has a high amount of surface friction and is almost sticky to the touch. Surface friction provides the material with a good grip. The grip provided by this rubber is why it is used in applications where traction is crucial, as in tires and shoes. It is also used in flooring and doormats for the same traction purposes.
- Good shock absorption: As with most elastomers, natural or “live rubber” possesses a characteristic shock absorbing molecular structure. This property is utilized in various applications that require impact absorption, sound insulation or vibration reduction. For example, modern music studios make extensive use of natural rubber material for the purposes of sound insulation.
Pure gum rubber is an incredible natural resource. In the aftermath of World War I, chemists attempted to replicate natural rubber using synthetic components. The goal was to create new rubbers tailor-made for certain applications like oil- and grease-resistance. Despite the surge in popularity for these synthetic elastomers, production of natural rubber never slowed down. Due to the mechanical properties of natural rubber there has and always will be a need for this flexible elastomer. Today, there are still many para tree farms where the main component for natural rubber is harvested; many manufacturers process the elastomer to a specific hardness, thickness, or blend. mechanical properties of natural rubber and pure gum rubber is sure to continue proving its value for centuries to come.