Unfilled PTFE
Unfilled PTFE is a grade of PTFE. It has the highest strength and highest ductility compared to the other variants of PTFE. The graph bars on the material properties cards below compare unfilled PTFE to: fluoroplastics (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
24 MPa 3.5 x 103 psi
Elastic (Young's, Tensile) Modulus
0.45 GPa 0.065 x 106 psi
Elongation at Break
300 %
Flexural Modulus
0.4 GPa 0.058 x 106 psi
Flexural Strength
50 MPa 7.3 x 103 psi
Impact Strength: Notched Izod
170 J/m 3.2 ft-lb/in
Tensile Strength: Ultimate (UTS)
25 MPa 3.6 x 103 psi
Thermal Properties
Glass Transition Temperature
-35 °C -31 °F
Heat Deflection Temperature At 1.82 MPa (264 psi)
70 °C 160 °F
Heat Deflection Temperature At 455 kPa (66 psi)
120 °C 250 °F
Maximum Temperature: Autoignition
630 °C 1170 °F
Maximum Temperature: Decomposition
540 °C 1000 °F
Maximum Temperature: Mechanical
270 °C 510 °F
Melting Onset (Solidus)
330 °C 630 °F
Specific Heat Capacity
1050 J/kg-K 0.25 BTU/lb-°F
Thermal Conductivity
0.24 W/m-K 0.14 BTU/h-ft-°F
Thermal Expansion
120 µm/m-K
Electrical Properties
Dielectric Constant (Relative Permittivity) At 1 MHz
2.1
Dielectric Strength (Breakdown Potential)
14 kV/mm 0.56 V/mil
Electrical Dissipation At 1 MHz
0.00017
Electrical Resistivity Order of Magnitude
18 10x Ω-m
Otherwise Unclassified Properties
Density
2.2 g/cm3 140 lb/ft3
Limiting Oxygen Index (LOI)
90 %
Refractive Index
1.4
Water Absorption After 24 Hours
0.0093 %
Common Calculations
Stiffness to Weight: Axial
0.12 points
Stiffness to Weight: Bending
12 points
Strength to Weight: Axial
3.2 points
Strength to Weight: Bending
8.7 points
Thermal Diffusivity
0.11 mm2/s
Thermal Shock Resistance
34 points
Followup Questions
Further Reading
Fluoroplastics: Volume 2 - Melt Processable Fluoropolymers, Sina Ebnesajjad, 2003
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