PEKK vs PPS
Polymer · grade comparison
PEKK and PPS are both polymer grades, both high performance plastic. PEKK is the stronger of the two: yield strength 95 MPa (13.8 ksi) against 75 MPa (10.9 ksi) for PPS, about 27% more; tensile strength follows at 95 MPa (13.8 ksi) vs 78 MPa (11.3 ksi). PEKK is the more ductile: elongation 8% versus 5% for PPS. PEKK is lighter (1.3 g/cm³ vs 1.35 g/cm³ for PPS) and PEKK runs hotter in service (240°C vs 220°C continuous). On the shop floor, PEKK welds better (good vs poor).
PEKKChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
PEKK vs PPS: 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
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Flexural Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Hardness, Rockwell R
Same in both: Shear Modulus 1.4 GPa0.2 Msi · Compressive Modulus 3.5 GPa0.51 Msi · Flexural Modulus 3.9 GPa0.57 Msi · Shear Strength 65 MPa9.4 ksi
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
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
Limiting Oxygen Index
Max Service Temperature (short-term)
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Volume Resistivity 1×10¹⁶ Ω·cm · Surface Resistivity 1×10¹⁵ Ω · Comparative Tracking Index (CTI) 175 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
UV / Weathering Resistance
Same in both: Corrosion Resistance 92 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Machinability 60 / 100 · Polishability 60 / 100 · Mold Shrinkage 1.2%
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Same in both: Thermal Diffusivity 0.2 mm²/s · 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 | PEKK | PPS |
|---|---|---|
| 3D printing | Yes | — |
| CNC machining | — | Yes |
| Sheet metal | — | Yes |
| Injection molding | — | Yes |
| Default condition | Unfilled | Unfilled |
| Relative cost | $$$$$ Specialty | $$$$$ Specialty |
| Min. machined wall | — | 0.5 mm |
| Best machined surface | — | Ra 0.8 µm |
| Chrome Plating (Plastic) | — | Yes |
| Conductive Coating | Yes | — |
| Dyeing (Nylon) | Yes | — |
| Primer Coating | Yes | — |
| Spray Painting | — | Yes |
| Tinted Coating | Yes | — |
| Vacuum Metallization | Yes | — |
| Waterproof Coating | Yes | — |
They share 4 finishes: EMI Shielding Coating, Painting, Soft Touch Coating, UV Coating.
PEKK vs PPS — frequently asked
Is PEKK stronger than PPS?
Yes. PEKK has a typical yield strength of 95 MPa (13.8 ksi) against 75 MPa (10.9 ksi) for PPS — about 27% more. Tensile strength is 95 MPa (13.8 ksi) vs 78 MPa (11.3 ksi).
Which is cheaper, PEKK or PPS?
Both sit in the same relative cost tier ($$$$$, specialty); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, PEKK or PPS?
PEKK. Its weldability rates good (55/100) against poor (30/100) for PPS.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PEKK and PPS 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.