Unfilled PBT
Unfilled PBT is a grade of PBT. The graph bars on the material properties cards below compare unfilled PBT to: polyester plastics (top), all thermoplastics (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Compressive (Crushing) Strength
76 MPa 11 x 103 psi
Elastic (Young's, Tensile) Modulus
2.7 GPa 0.39 x 106 psi
Elongation at Break
43 %
Flexural Modulus
2.6 GPa 0.38 x 106 psi
Flexural Strength
79 MPa 11 x 103 psi
Impact Strength: Notched Izod
47 J/m 0.88 ft-lb/in
Rockwell R Hardness
120
Tensile Strength: Ultimate (UTS)
58 MPa 8.4 x 103 psi
Thermal Properties
Glass Transition Temperature
40 °C 100 °F
Heat Deflection Temperature At 1.82 MPa (264 psi)
4.0 °C 39 °F
Heat Deflection Temperature At 455 kPa (66 psi)
160 °C 310 °F
Maximum Temperature: Autoignition
380 °C 720 °F
Maximum Temperature: Decomposition
380 °C 720 °F
Maximum Temperature: Mechanical
110 °C 230 °F
Melting Onset (Solidus)
230 °C 440 °F
Specific Heat Capacity
1200 J/kg-K 0.29 BTU/lb-°F
Thermal Conductivity
0.21 W/m-K 0.12 BTU/h-ft-°F
Thermal Expansion
84 µm/m-K
Vicat Softening Temperature
190 °C 370 °F
Electrical Properties
Dielectric Constant (Relative Permittivity) At 1 Hz
3.4
Dielectric Strength (Breakdown Potential)
26 kV/mm 1.0 V/mil
Electrical Dissipation At 1 Hz
0.0020
Electrical Resistivity Order of Magnitude
13 10x Ω-m
Otherwise Unclassified Properties
Density
1.3 g/cm3 83 lb/ft3
Limiting Oxygen Index (LOI)
20 %
Water Absorption After 24 Hours
0.070 %
Common Calculations
Stiffness to Weight: Axial
1.1 points
Stiffness to Weight: Bending
35 points
Strength to Weight: Axial
12 points
Strength to Weight: Bending
25 points
Thermal Diffusivity
0.13 mm2/s
Thermal Shock Resistance
18 points
Followup Questions
Further Reading
SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., 5th ed., Michael L. Berins (editor), 2000
Modern Plastics Handbook, Charles A. Harper (editor), 1999
Plastics Materials, 7th ed., J. A. Brydson, 1999
Advanced Materials in Automotive Engineering, Jason Rowe (editor), 2012