PBT vs PTMT
Polymer · grade comparison
PBT and PTMT are both polymer grades. Both yield at about 55 MPa — strength does not separate them. PTMT runs hotter in service (120°C vs 110°C continuous). On the shop floor, PTMT forms better (30 vs 20 out of 100).
PTMTChoose it when the part sees heat.
PBT vs PTMT: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Shear Modulus
Bulk Modulus
Fracture Toughness (K_IC)
Hardness, Rockwell M
Same in both: Elastic (Young's) Modulus 2.6 GPa0.38 Msi · Poisson's Ratio 0.4 · Tensile Strength (Ultimate) 55 MPa8 ksi · Yield Strength (0.2% offset) 55 MPa8 ksi · Elongation at Break 100% · Compressive Strength 85 MPa12.3 ksi · Compressive Modulus 2.4 GPa0.35 Msi · Flexural Strength 88 MPa12.8 ksi · Flexural Modulus 2.4 GPa0.35 Msi · Shear Strength 45 MPa6.5 ksi · Izod Impact, Notched 50 J/m0.94 ft·lbf/in · Hardness, Shore D 82 Shore D · Hardness, Rockwell R 118 HRR
Physical
Density and transition temperatures.
Glass Transition (Tg)
Water Absorption (24 h)
Refractive Index
Same in both: Density 1.31 g/cm³0.05 lb/in³ · Melting Temperature (Tm) 225°C437 °F · Water Absorption (Saturation) 0.45%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Heat Deflection Temp. @ 0.45 MPa
Same in both: Specific Heat Capacity 1,500 J/kg·K0.36 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 80 µm/m·K44.4 µin/in·°F · Min Service Temperature -40°C-40 °F · Heat Deflection Temp. @ 1.8 MPa 60°C140 °F · Vicat Softening Point (B50) 178°C352 °F · Limiting Oxygen Index 21% · Max Service Temperature (short-term) 160°C320 °F
Electrical
Conductivity and insulation.
Dielectric Strength
Dissipation Factor (1 MHz)
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Dielectric Constant (1 MHz) 3.1 · Volume Resistivity 1×10¹⁶ Ω·cm · Surface Resistivity 1×10¹⁵ Ω · Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: UV / Weathering Resistance 35 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Formability (cold)
Polishability
Mold Shrinkage
Processing Melt Temperature (typ.)
Same in both: Machinability 68 / 100 · Weldability 70 / 100 · Melt Flow Rate 25 g/10 min · Mold Temperature (typ.) 70°C158 °F
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Same in both: Embodied Water 250 L/kg30 gal/lb · Typical Recycled Content 5%
Common Calculations
Ratios derived from the values above.
Same in both: Specific Strength (UTS / density) 42 kN·m/kg · Specific Stiffness (E / density) 2 MN·m/kg · Modulus of Resilience 582 kJ/m³ · Thermal Diffusivity 0.1 mm²/s · Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | PBT | PTMT |
|---|---|---|
| Injection molding | Yes | — |
| Default condition | Unfilled | — |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
| Chrome Plating (Plastic) | Yes | — |
| EMI Shielding Coating | Yes | — |
| Soft Touch Coating | Yes | — |
| Spray Painting | Yes | — |
| UV Coating | Yes | — |
PBT vs PTMT — frequently asked
What is the difference between PBT and PTMT?
PBT and PTMT are both polymer grades. Both yield at about 55 MPa — strength does not separate them. PTMT runs hotter in service (120°C vs 110°C continuous).
Which is cheaper, PBT or PTMT?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose PBT over PTMT?
Pick PTMT when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PBT and PTMT side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.