Natural rubber (NR) is produced from the latex of the Hevea brasiliensis tree and is chemically classified as polyisoprene. Once vulcanized with sulfur, it becomes one of the most resilient and mechanically capable elastomers available, which is why it remains a benchmark material despite the wide range of synthetic rubbers developed since.
Key properties
NR offers excellent tensile strength, tear resistance, and elasticity, along with very high resilience (rebound), which means parts made from it absorb and release energy efficiently rather than losing it as heat.
It also has outstanding resistance to flex fatigue — the ability to withstand millions of bending or flexing cycles without cracking — which makes it a strong candidate for components that move repeatedly, such as bellows, boots, and vibration-damping parts.
Unmodified NR has relatively poor resistance to ozone, UV exposure, and oxidation, and it swells significantly in contact with oils, fuels, and most hydrocarbon solvents. It also has a lower practical temperature ceiling than many synthetic elastomers.
Typical applications
Because of its flex fatigue resistance and elasticity, natural rubber is a common choice for bellows, protective boots, mounts, and other parts subjected to continuous flexing or vibration, particularly where the operating environment is not oil- or fuel-rich.
It is also widely used in tires, shock absorbers, and general-purpose molded goods where mechanical toughness matters more than chemical or weathering resistance.
Things to confirm before specifying
Hardness, temperature range, and other mechanical values depend on the specific compound and should be confirmed against a production datasheet rather than general literature values before finalizing a design.
If a part will be exposed to prolonged sunlight, ozone-rich environments, or oils and fuels, a compounded or blended elastomer (or an alternative such as EPDM for weathering, or NBR for oil resistance) is usually preferable to unmodified NR.