PETG vs. IR Grade Fused Silica
PETG and IR grade fused silica belong to fundamentally different material chemistries. PETG is a polymeric material, while IR grade fused silica is ceramic. Therefore, their performance will be even more dissimilar than would be suggested by the difference in properties. There are 18 material properties with values for both materials. Properties with values for just one material (17, in this case) are not shown.
For each property being compared, the top bar is PETG and the bottom bar is IR grade fused silica.
Metric UnitsUS Customary Units
Mechanical Properties
| Compressive (Crushing) Strength, MPa | 55 | |
| 1100 |
| Elastic (Young's, Tensile) Modulus, GPa | 2.2 | |
| 73 |
| Flexural Strength, MPa | 77 | |
| 67 |
| Tensile Strength: Ultimate (UTS), MPa | 53 | |
| 50 |
Thermal Properties
| Melting Onset (Solidus), °C | 140 | |
| 1900 |
| Specific Heat Capacity, J/kg-K | 1200 | |
| 720 |
| Thermal Conductivity, W/m-K | 0.29 | |
| 1.4 |
| Thermal Expansion, µm/m-K | 68 | |
| 0.5 |
Electrical Properties
| Dielectric Constant (Relative Permittivity) At 1 MHz | 2.4 | |
| 3.8 |
| Dielectric Strength (Breakdown Potential), kV/mm | 16 | |
| 30 |
Otherwise Unclassified Properties
| Density, g/cm3 | 1.3 | |
| 2.2 |
| Refractive Index | 1.6 | |
| 1.5 |
Common Calculations
| Stiffness to Weight: Axial, points | 1.0 | |
| 18 |
| Stiffness to Weight: Bending, points | 34 | |
| 63 |
| Strength to Weight: Axial, points | 12 | |
| 6.3 |
| Strength to Weight: Bending, points | 25 | |
| 14 |
| Thermal Diffusivity, mm2/s | 0.19 | |
| 0.85 |
| Thermal Shock Resistance, points | 25 | |
| 97 |