Teflon:
Teflon has a scientific name of polytetrafluoroethylene (PTFE), and is the most commonly used fluorinated polymer.
PTFE has excellent resistance against heat and chemicals as well as good dielectric properties. It is characterized by having a low coefficient of friction and non-stickiness.
Teflon is considered a none-heat-processible high molecular weight fluorinated compound. About 60% of the compound is composed of fluorine.
These compounds include PVDF, FEP, E-CTFE, PVF, E-TFE, PFA, and CTFE-VDF. The overall properties of PTFE makes it better compared to other high molecular weight fluorinated polymers.
PTFE has 3 different forms:
- Resin granules: For die casting of parts and plates as well as extrusion of pipes and rods
- Powder: Used for extrusion of plates
- Aqueous dispersion: Used for coating and production of fiber
Filled Teflon would be produced by mixing the resin granules with other fillers. Fillers can be used to improve the mechanical properties of the Teflon.
The diagram below summarizes the properties of PTFE and its ranking compared to other high molecular weight fluorinated polymers.
Comparison between different high molecular weight fluorinated polymers :
|
PTFE |
FEP |
PFA |
E-TFE |
E-CTFE |
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Weight |
2.13~2.20 |
2.14~2.17 |
2.12~2.17 |
1.70 |
1.68~1.69 |
|
Tensile strength (Mpa) |
13.7~34.3 |
18.6~19.6 |
29.4 |
45.1 |
48 |
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Tensile elongation (%) |
200~400 |
250~330 |
300 |
100~400 |
200 |
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Flexural modulus (Mpa) |
0.34~0.62 |
0.66 |
0.66 |
1.37 |
1.65 |
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Operating temperatures (max﹐℃) |
260 |
200 |
260 |
150~180 |
160~180 |
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Heat deflection temperature (℃﹐ 451kPa) |
121 |
70 |
73 |
104 |
116 |
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Volume resistivity (Ω-cm) |
>1018 |
>1018 |
>1018 |
>1018 |
1015 |
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Dielectric constant (1kHz) |
2.6 |
2.3 |
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Dielectric dissipation factor (1kHz) |
0.0002 |
0.0008 |
0.0015 |
Main properties of Teflon:
The extremely strong carbon-fluorine bonds and high molecular weight of PTFE Teflon gives it a number of excellent properties listed below:
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Excellent electrical properties (that do not change with frequency or temperature) |
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