Isoprene (Natural) Rubber (IR, NR)
IR rubber is a thermoset elastomer or rubber material. It has a fairly low density among rubber materials. In addition, it has the highest ductility and the lowest thermal conductivity. The graph bars on the material properties cards below compare IR rubber to other rubber materials (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elongation at Break
600 %
Tensile Strength: Ultimate (UTS)
19 MPa 2.8 x 103 psi
Thermal Properties
Glass Transition Temperature
-70 °C -94 °F
Maximum Temperature: Autoignition
300 °C 560 °F
Maximum Temperature: Decomposition
300 °C 570 °F
Specific Heat Capacity
1550 J/kg-K 0.37 BTU/lb-°F
Thermal Conductivity
0.14 W/m-K 0.081 BTU/h-ft-°F
Otherwise Unclassified Properties
Density
1.0 g/cm3 59 lb/ft3
Limiting Oxygen Index (LOI)
19 %
Common Calculations
Strength to Weight: Axial
5.6 points
Strength to Weight: Bending
17 points
Thermal Diffusivity
0.1 mm2/s
Followup Questions
Further Reading
Rubber Formulary, The, Peter A. Ciullo and Norman Hewitt, 1999