PET vs. PEI
Both PET and PEI are thermoplastics. There are 17 material properties with values for both materials. Properties with values for just one material (14, in this case) are not shown.
For each property being compared, the top bar is PET and the bottom bar is PEI.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 3.5 to 11 | |
| 3.4 to 5.6 |
| Elongation at Break, % | 2.5 to 70 | |
| 3.0 to 34 |
| Flexural Modulus, GPa | 8.3 to 14 | |
| 3.4 to 5.9 |
| Impact Strength: Notched Izod, J/m | 43 to 85 | |
| 55 to 110 |
| Tensile Strength: Ultimate (UTS), MPa | 60 to 140 | |
| 110 to 160 |
Thermal Properties
| Glass Transition Temperature, °C | 70 | |
| 210 |
| Maximum Temperature: Autoignition, °C | 410 | |
| 530 |
| Maximum Temperature: Decomposition, °C | 390 | |
| 530 |
| Maximum Temperature: Mechanical, °C | 80 | |
| 170 |
| Specific Heat Capacity, J/kg-K | 1000 to 1150 | |
| 1050 to 1220 |
Otherwise Unclassified Properties
| Density, g/cm3 | 1.4 to 1.6 | |
| 1.3 to 1.5 |
| Limiting Oxygen Index (LOI), % | 21 | |
| 47 to 50 |
| Water Absorption At Saturation, % | 0.24 to 0.5 | |
| 0.9 to 1.3 |
Common Calculations
| Stiffness to Weight: Axial, points | 1.2 to 4.4 | |
| 1.5 to 2.1 |
| Stiffness to Weight: Bending, points | 32 to 54 | |
| 39 |
| Strength to Weight: Axial, points | 12 to 27 | |
| 24 to 30 |
| Strength to Weight: Bending, points | 25 to 41 | |
| 40 to 44 |