PEEK vs. PET
Both PEEK and PET are thermoplastics. There are 18 material properties with values for both materials. Properties with values for just one material (12, in this case) are not shown.
For each property being compared, the top bar is PEEK and the bottom bar is PET.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 4.0 to 24 | |
| 3.5 to 11 |
| Elongation at Break, % | 1.6 to 43 | |
| 2.5 to 70 |
| Flexural Modulus, GPa | 3.8 to 19 | |
| 8.3 to 14 |
| Impact Strength: Notched Izod, J/m | 78 to 120 | |
| 43 to 85 |
| Tensile Strength: Ultimate (UTS), MPa | 97 to 200 | |
| 60 to 140 |
Thermal Properties
| Glass Transition Temperature, °C | 240 | |
| 70 |
| Maximum Temperature: Autoignition, °C | 600 | |
| 410 |
| Maximum Temperature: Decomposition, °C | 570 | |
| 390 |
| Maximum Temperature: Mechanical, °C | 330 | |
| 80 |
| Melting Onset (Solidus), °C | 340 | |
| 260 |
| Specific Heat Capacity, J/kg-K | 1390 to 1700 | |
| 1000 to 1150 |
Otherwise Unclassified Properties
| Density, g/cm3 | 1.3 to 1.5 | |
| 1.4 to 1.6 |
| Limiting Oxygen Index (LOI), % | 38 | |
| 21 |
| Water Absorption At Saturation, % | 0.22 to 0.5 | |
| 0.24 to 0.5 |
Common Calculations
| Stiffness to Weight: Axial, points | 1.5 to 10 | |
| 1.2 to 4.4 |
| Stiffness to Weight: Bending, points | 36 to 73 | |
| 32 to 54 |
| Strength to Weight: Axial, points | 20 to 41 | |
| 12 to 27 |
| Strength to Weight: Bending, points | 36 to 55 | |
| 25 to 41 |