Thermoplastic comparison
PEI (Ultem) vs Polylactic acid (PLA)
Every value below is a typical room-temperature figure with its source, test method and conditions — the same dataset that drives the calculators.
| Property | PEI (Ultem) | Polylactic acid (PLA) | Difference |
|---|---|---|---|
| Density | 1.27 g/cm³ | 1.24 g/cm³ | PEI (Ultem) — 2% higher |
| Young's modulus E | 3.2 GPa | 3.5 GPa | Polylactic acid (PLA) — 9% higher |
| Tensile strength | 105 MPa | 50 MPa | PEI (Ultem) — 2.1× higher |
| Glass transition Tg | 217 °C | 58 °C | PEI (Ultem) — 159 °C higher |
Where these numbers come from
- CAMPUS plastics database — typical grade datasheet values (campusplastics.com)
- Farah, Anderson & Langer, Adv. Drug Deliv. Rev. 107 (2016) 367–392 — comprehensive PLA property review
- MakeItFrom.com materials database — typical grade values
Typical room-temperature values for learning and preliminary design; grades vary widely and a supplier datasheet always overrides a textbook figure. Confirm against the datasheet before design work.