Sep 5 2001
Polytetrafluoroethylene (PTFE) is a totally fluorinated polymer which is white, semi-opaque, and semi-crystalline. It has excellent chemical resistance, is unaffected by nearly all chemicals, and has a very high oxygen index (i.e. is inherently non-flammable). It is stable to high temperatures and has a very low coefficient of friction.
It is soft, easily deformed, low in strength, and has very low creep resistance with poor radiation resistance. PTFE is relatively expensive and cannot be melt-processed (albeit theoretically, it melts at 327 °C, the melt viscosity of normal grades is almost infinite) and so is formed by powder sintering methods.
Polymer Type
Thermoplastic
Advantages
Outstanding chemical resistance. Low coefficient of friction. High continuous use temperature (c 180 °C/360 °F). Very high oxygen index.
Disadvantages
High cost. Low strength and stiffness. Cannot be melt processed. Poor radiation resistance.
Applications
Bearings, chemical vessel linings, pipe and valve linings, gaskets, diaphragms, piston rings, high temperature electrical insulation. As a coating for non-stick applications.
Industrial applications include O-rings, seals, and non-stick coatings and linings for vessels. PTFE’s unique properties make it perfect for a wide range of laboratory applications.
Typical Properties
| Property |
Value |
| Density (g/cm3) |
2.15 |
| Surface Hardness |
SD63 |
| Tensile Strength (MPa) |
25 |
| Flexural Modulus (GPa) |
0.70 |
| Notched Izod (kJ/m) |
0.16 |
| Linear Expansion (/°C x 10-5) |
15 |
| Elongation at Break (%) |
400 |
| Strain at Yield (%) |
70 |
| Max. Operating Temp. (°C) |
180 |
| Water Absorption (%) |
0.01 |
| Oxygen Index (%) |
95 |
| Flammability UL94 |
V0 |
| Volume Resistivity (log ohm.cm) |
18 |
| Dielectric Strength (MV/m) |
45 |
| Dissipation Factor 1 kHz |
0.0001 |
| Dielectric Constant 1 kHz |
2.1 |
| HDT @ 0.45 MPa (°C) |
121 |
| HDT @ 1.80 MPa (°C) |
54 |
| Material. Drying hrs @ (°C) |
NA |
| Melting Temp. Range (°C) |
NA |
| Mould Shrinkage (%) |
NA |
| Mould Temp. Range (°C) |
NA |