Full definition
cis-1,4-polyisoprene harvested as latex from the Hevea brasiliensis tree (rubber tree), the original and still one of the most important industrial elastomers. NR provides an unmatched combination of high elasticity (elongation 600-900%), excellent tear resistance (50-100 kN/m), low hysteresis/heat buildup (rebound resilience ~80%), high tensile strength without reinforcing fillers (due to strain crystallization — unique to NR), and outstanding dynamic fatigue life. Temperature range: -55 to +70°C continuous (+100°C short-term). ASTM D2000 classification: AA. Limitations: poor resistance to oils, fuels, ozone (requires protection), and UV; degrades above 100°C. Grades: RSS (ribbed smoked sheets — visual quality grading), TSR/SMR/SIR/STR (technically specified rubber — tested for dirt, ash, nitrogen, volatile content). Origin: 85%+ from Southeast Asia (Thailand, Indonesia, Vietnam, Malaysia). Global production: ~14 million tonnes/year. Applications: truck and aircraft tires (largest use), conveyor belt covers, anti-vibration mounts, bridge bearings (AASHTO M 251), latex gloves, and elastic bands. NR remains irreplaceable in applications requiring high resilience and dynamic endurance.