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Technical Description
Discovered in 1938 by Dr. Roy J. Plunkett of the DuPont Company, PTFE is a fluorocarbon-based polymer. PolyTetraFluoroEthylene is commonly abbreviated PTFE, and the PTFE brand of PTFE is manufactured only by DuPont. the fluoroplastic family off ers plastics with high chemical resistance, low an dhigh temperature capabiltiy, resistance to weathering, low friction, electrical and thermal insulation, and "slipperiness".
General Properties
PTFE mechanical properties are low compared to other plastics, but its properties remain at a useful level over a wide temperature range of -100°F to +400°F (-73°C to 204°C). Mechanical properties are often enhanced by adding fillers (see filled grades below). It has excellent thermal and electrical insulation properties and a low coefficient of friction. PTFE is very dense and connto be melt processed - it must be compressed and sintered to form useful shapes.
Filled Grades
PTFE's mechanical properties can be enhanced by adding fillers such as glass fibers, carbon, graphite, molybdenum disulphide, and bronze. Generally, filled PTFE's maintain their excellent chemical and high temperature characteristics, while fillers improve mechanical strength, stability, and wear resistance. The properties of 25% glass-filled PTFE grade are shown below. There are literally dozens of different filled PTFE products and grades - too many to be listed here. Please contact EPM for more information about other filled PTFE products for your application. |
TYPICAL PROPERTIES of PTFE
|
| ASTM or UL test |
Property |
PTFE
(unfilled) |
PTFE
(25% glass filled) |
| PHYSICAL |
| D792 |
Density (lb/in?)
(g/cm?) |
0.079
2.2 |
0.081
2.24 |
| D570 |
Water Absorption, 24 hrs (%) |
< 0.01 |
0.02 |
| MECHANICAL |
| D638 |
Tensile Strength (psi) |
6,000 |
2,700 |
| D638 |
Tensile Modulus (psi) |
80,000 |
- |
| D638 |
Tensile Elongation at Break (%) |
300 |
270 |
| D790 |
Flexural Strength (psi) |
No break |
1,800 |
| D790 |
Flexural Modulus (psi) |
27,000 |
19,000 |
| D695 |
Compressive Strength (psi) |
3,500 |
1,500 |
| D695 |
Compressive Modulus (psi) |
70,000 |
110,000 |
| D785 |
Hardness, Shore D |
D50-65 |
D54 |
| D256 |
IZOD Notched Impact (ft-lb/in) |
3.5 |
2.0 |
| THERMAL |
| D696 |
Coefficient of Linear Thermal Expansion
(x 10-5 in./in./°F) |
7.5 |
5.0 |
| D648 |
Heat Deflection Temp (°F / °C)
at 264 psi |
132 / 55 |
150 / 65 |
| D3418 |
Melting Temp (°F / °C) |
635 / 335 |
635 / 335 |
| - |
Max Operating Temp (°F / °C) |
500 / 260 |
500 / 260 |
| C177 |
Thermal Conductivity
(BTU-in/ft?-hr-°F)
(x 10-4 cal/cm-sec-°C) |
1.70
5.86 |
3.1
10.6 |
| UL94 |
Flammability Rating |
V-O |
V-O |
| ELECTRICAL |
| D149 |
Dielectric Strength (V/mil) short time, 1/8" thick |
285 |
- |
| D150 |
Dielectric Constant at 1 MHz |
2.1 |
2.4 |
| D150 |
Dissipation Factor at 1 MHz |
< 0.0002 |
0.05 |
| D257 |
Volume Resistivity (ohm-cm)at 50% RH |
> 1018 |
> 1015 |
Note: The information contained herein are typical values intended for reference and comparison purposes only. They should not be used as basis for design specifications or quality control. Contact us for manufacturers' complete material property datasheets. All values at 73°F (23°C unless otherwise noted.
PTFE is a registered trademark of DuPont
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