Thermoplastic comparison
PET vs Polystyrene (GPPS)
Every value below is a typical room-temperature figure with its source, test method and conditions — the same dataset that drives the calculators.
| Property | PET | Polystyrene (GPPS) | Difference |
|---|---|---|---|
| Density | 1.37 g/cm³ | 1.05 g/cm³ | PET — 30% higher |
| Young's modulus E | 2.9 GPa | 3.2 GPa | Polystyrene (GPPS) — 10% higher |
| Tensile strength | 60 MPa | 46 MPa | PET — 30% higher |
| Glass transition Tg | 76 °C | 100 °C | Polystyrene (GPPS) — 24 °C higher |
Where these numbers come from
- Callister & Rethwisch, Materials Science and Engineering, 10th ed.
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.