EPDM vs NBR
Polymer · grade comparison
EPDM and NBR are both polymer grades. NBR is the stronger of the two: tensile strength 16 MPa (2.32 ksi) against 12 MPa (1.74 ksi) for EPDM, about 33% more. EPDM is lighter (1.15 g/cm³ vs 1.25 g/cm³ for NBR) and EPDM runs hotter in service (120°C vs 100°C continuous).
EPDMChoose it when weight is the constraint, or when the part sees heat.
NBRChoose it when strength drives the design.
EPDM vs NBR: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Compression Set (22 h, 70 °C)
Shear Strength
Same in both: Elastic (Young's) Modulus 0.01 GPa8.7×10⁻⁴ Msi · Elongation at Break 400% · Hardness, Shore A 70 Shore A · Hardness, Shore D 22 Shore D · Tear Strength 25 kN/m143 lbf/in
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (Saturation)
Same in both: Water Absorption (24 h) 0.5%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Max Service Temperature (short-term)
Same in both: Limiting Oxygen Index 19%
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
Comparative Tracking Index (CTI)
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Machinability 30 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 5%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Same in both: Specific Stiffness (E / density) 0 MN·m/kg · Thermal Diffusivity 0.1 mm²/s · Thermal Shock Resistance Index 3
Strength versus weight
Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | EPDM | NBR |
|---|---|---|
| Default condition | Solid | Solid |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both are offered for Injection molding. Both take the same 5 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Soft Touch Coating, Spray Painting, UV Coating.
EPDM vs NBR — frequently asked
Is NBR stronger than EPDM?
Yes. NBR has a typical tensile strength of 16 MPa (2.32 ksi) against 12 MPa (1.74 ksi) for EPDM — about 33% more.
Which is cheaper, EPDM or NBR?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, EPDM or NBR?
EPDM. Its weldability rates poor (15/100) against not recommended (10/100) for NBR.
Ready to make it?
Upload a CAD file and FabDigit prices the part in EPDM and NBR side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.