Rubber

Rubber strength, stiffness, density and thermal properties, with their source.

A bracket in Rubber, smooth finish.

Mechanical
Yield strength	not given (tensile used)
Ultimate tensile strength	23MPa1
Elongation at break	830%1
Young's modulus (stiffness)	not sourced
Density	960kg/m³1
Strength to weight	24kN·m/kg
Stiffness to weight	not sourced
Poisson's ratio	government0.52
Shear modulus	not sourced
Bulk modulus	not sourced
Speed of sound	not sourced

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal
Thermal conductivity	0.151W/m·K3
Thermal expansion	not sourced
100 mm part over a 50 °C swing	not sourced
Specific heat	government1,881J/kg·K2
Heats up and cools (diffusivity)	0.0836mm²/s
Thermal shock resistance	not sourced
Max service temperature	70°C1

Thermal conductivity against densityHigher and further left: spreads more heat for its weight

Thermal expansion against thermal conductivityLower and further right: warps less when heated

Sources3 documents: Weir Minerals, National Institute of Standards and Technology, Defense Technical Information Center

Values for: Bulk polymer (molded or machined). Weir Minerals Linatex Premium rubber (95 % natural rubber), typical physical properties, spec sheet WMD0118/202305

1
Linatex Premium Rubber Spec Sheet (WMD0118, 2023)Weir MineralsUltimate tensile strength: typicalElongation at break: typicalDensity: typical (specific gravity)Max service temperature: continuous use operating range
2
Compressibility of Natural Rubber at Pressures Below 500 kg/cm², J. Res. NBS 68A (1964)National Institute of Standards and Technologyarchived copyPoisson's ratio: government (NBS J. Res. 68A, 1964): computed by NBS for peroxide-cured gum NR vulcanizate, 25 °C, infinitesimal deformation (0.49 in the solver: the linear element locks as the ratio nears 0.5 (nearly incompressible).)Specific heat: government (NBS J. Res. 68A, Table 7; values observed for unvulcanized NR by Bekkedahl and Matheson), 25 °C
3
Thermal Conductivity of Soft Vulcanized Natural Rubber: Selected Values (AD 643325)Defense Technical Information Centerarchived copyThermal conductivity: government selected value (US Army Natick Laboratories TR 66-49-PR, 1966), soft vulcanized natural rubber, 25 °C

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Thermal properties of Rubber

Thermal conductivity of Rubber

Rubber has a thermal conductivity of 0.151 W/m·K (0.0872 BTU/hr·ft·°F). Basis: government selected value (US Army Natick Laboratories TR 66-49-PR, 1966), soft vulcanized natural rubber, 25 °C. Source: Defense Technical Information Center, Thermal Conductivity of Soft Vulcanized Natural Rubber: Selected Values (AD 643325)archived copy.

Specific heat of Rubber

The specific heat capacity of Rubber is 1,881 J/kg·K (0.449 BTU/lb·°F). Basis: government (NBS J. Res. 68A, Table 7; values observed for unvulcanized NR by Bekkedahl and Matheson), 25 °C. Source: National Institute of Standards and Technology, Compressibility of Natural Rubber at Pressures Below 500 kg/cm², J. Res. NBS 68A (1964)archived copy.

Thermal diffusivity of Rubber

Computed from the conductivity, density and specific heat (k / ρc): 0.0836 mm²/s, how fast a temperature change spreads through it.

Maximum service temperature of Rubber

The maximum service temperature of Rubber is 70 °C (158 °F). Basis: continuous use operating range. Source: Weir Minerals, Linatex Premium Rubber Spec Sheet (WMD0118, 2023).