PEI vs PMP
Polymer · grade comparison
PEI and PMP are both polymer grades. PEI is the stronger of the two: yield strength 105 MPa (15.2 ksi) against 24 MPa (3.48 ksi) for PMP, about 4.4 times as much; tensile strength follows at 105 MPa (15.2 ksi) vs 25 MPa (3.63 ksi). PEI is the more ductile: elongation 60% versus 20% for PMP, and PEI is harder (87 Shore D vs 70 Shore D). PMP is lighter (0.83 g/cm³ vs 1.27 g/cm³ for PEI) and PEI is stiffer (3.2 GPa vs 1.5 GPa). On the shop floor, PEI welds better (good vs fair) and PMP sits in a lower cost tier (high, $$$$) than PEI (specialty, $$$$$).
PEIChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
PMPChoose it when weight is the constraint, or when cost is the deciding factor.
PEI vs PMP: 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Hardness, Rockwell R
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Refractive Index
Light Transmission
Melting Temperature (Tm)
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
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Limiting Oxygen Index
Same in both: Max Service Temperature (short-term) 200°C392 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
Comparative Tracking Index (CTI)
Same in both: Surface Resistivity 1×10¹⁶ Ω
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)
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Machinability 65 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Same in both: Thermal Shock Resistance Index 0
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 | PEI | PMP |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Injection molding | Yes | — |
| 3D printing | Yes | — |
| Default condition | Unfilled (1000) | — |
| Relative cost | $$$$$ Specialty | $$$$ High |
| Min. machined wall | 0.5 mm | — |
| Best machined surface | Ra 0.8 µm | — |
| Chrome Plating (Plastic) | Yes | — |
| Conductive Coating | Yes | — |
| Dyeing (Nylon) | Yes | — |
| EMI Shielding Coating | Yes | — |
| Painting | Yes | — |
| Primer Coating | Yes | — |
| Soft Touch Coating | Yes | — |
| Spray Painting | Yes | — |
| Tinted Coating | Yes | — |
| UV Coating | Yes | — |
| Vacuum Metallization | Yes | — |
| Waterproof Coating | Yes | — |
PEI vs PMP — frequently asked
Is PEI stronger than PMP?
Yes. PEI has a typical yield strength of 105 MPa (15.2 ksi) against 24 MPa (3.48 ksi) for PMP — about 4.4 times as much. Tensile strength is 105 MPa (15.2 ksi) vs 25 MPa (3.63 ksi).
Which is cheaper, PEI or PMP?
PMP is the lower-cost material: it sits in the high tier ($$$$) while PEI is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which welds better, PEI or PMP?
PEI. Its weldability rates good (60/100) against fair (50/100) for PMP.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PEI and PMP 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.