Polytetrafluoroethylene
PTFE – The original fluoropolymer. Accidentally discovered by Roy Plunkett in 1938 whilst working for a subsidiary of the DuPont organisation. PTFE is a synthetic polymer of tetrafluoroethylene. Its properties of low friction (non-stick) and inertness (chemical resistance) and high temperature stability, have led to its use in such diverse environments as non-stick cookware, sealant tape, chemical linings, labware and inside the human body. PTFE is widely used in various industries, including manufacturing, electronics, automotive, and more.
The key properties of PTFE are:
- Unsurpassed Non Stick properties
- Excellent chemical resistance
- Operating temperature up to 250°C
- Superb Electrical properties – low dielectric constant
- Inert
- Excellent weatherability
It is not a melt processable fluoropolymer and cannot therefore be extruded by usual extrusion technology, as a result Holscot do not generally offer products made from this material, instead offer products made from FEP, PFA and ETFE.
Trade Names for PTFE resins include DuPont Teflon™, Daikin Neoflon™, AGC Fluon™, 3M Dyneon™, Solvay Solexis Algoflon™
Summary of PTFE to other fluoropolymers like FEP, PFA, and ETFE:
- Chemical Structure: PTFE is a homopolymer of tetrafluoroethylene. Unlike the other fluoropolymers you mentioned (FEP, PFA, and ETFE), which are copolymers of various fluorinated monomers, PTFE is made from a single monomer.
- Mechanical Properties: PTFE has relatively low tensile strength and can deform under load at room temperature. It is also less flexible than some of the other fluoropolymers, which can limit its use in applications that require significant flexing.
- Temperature Range: PTFE has an exceptional temperature range, being able to withstand temperatures from approximately -200°C to +260°C (-328°F to +500°F). This makes it suitable for high-temperature applications.
- Chemical Resistance: PTFE is known for its outstanding chemical resistance. It is virtually inert to most chemicals and solvents, making it an ideal material for applications involving corrosive substances.
- Non-Stick Properties: PTFE’s non-stick characteristics are unmatched. It’s used in cookware (like Teflon-coated pans) because of its ability to prevent sticking of food.
- Transparency: Unlike some other fluoropolymers, PTFE is not transparent and has a white, opaque appearance.
- Electrical Properties: PTFE is an excellent electrical insulator and has low dielectric constant and dissipation factor.
- Processing Difficulty: PTFE is difficult to process due to its high melt viscosity and low thermal conductivity. It requires specialized processing techniques.
- Cost: PTFE can be expensive due to its unique properties and processing challenges.
Comparing PTFE to other fluoropolymers:
- FEP (Fluorinated Ethylene Propylene): FEP has better mechanical properties than PTFE and can be melt-processed. It also has transparency and good electrical properties, unlike PTFE.
- PFA (Perfluoroalkoxy): PFA combines some of the best attributes of PTFE and FEP. It offers chemical resistance similar to PTFE while being melt-processable like FEP. PFA’s temperature range falls between PTFE and FEP.
- ETFE (Ethylene Tetrafluoroethylene): ETFE has better mechanical strength than PTFE, is more transparent, and has good chemical resistance. It’s often used for architectural purposes and in the aerospace industry.
In summary, PTFE is known for its exceptional chemical resistance, high-temperature stability, and non-stick properties. It differs from other fluoropolymers like FEP, PFA, and ETFE in terms of its chemical structure, mechanical properties, processing difficulty, and specific applications for which it’s best suited.
Technical Data for PTFE:
| Property | Value | Units | Method |
|---|---|---|---|
| Mechanical Properties | |||
| Tensile Strength, 23°C | 2500 17 |
psi MPa |
|
| Elongation, 23°C | 200-500 | % | |
| Flexural Strength, 23°C | No break at flexure | D 790 | |
| Impact Strength, Izod | 3.2 173 |
Ft-lbs/in j/m |
|
| Yield Strength At 23°C | 1450 | psi | |
| Density | 2.17 | gm/cu.cm | |
| Thermal Properties | |||
| Melting Point | 327 | °C | |
| Thermal Conductivity | 1.7 0.25 |
Btu/hr-.ft-deg F W/m/deg K |
|
| Service Temperature | 260 | °C | |
| Processing Temperature | 370-395 | °C | |
| Electrical Properties | |||
| Dielectric Strength, short time, 2mm | 18 | Volts/mum | |
| Volume Resistivity, dry, @ 50% RH | >1018 | ohm-cm | D 257 |
| Dielectric Constant, 60 to 2 x 109 cps | 2.1 | ε | D150-81 |
| Other Properties | |||
| Flame Rating+ | VE-0 | UL-94 | |
| Resistance to Weathering | Excellent | ||
| Specific Gravity | 2.17 | D792-66 (1979) | |
| Coefficient of friction | 0.27–0.67 | D 1894 | |
Why Holscot?
- Proven manufacture, knowledgeable project management experience and excellent customer service all come as part of the package when working with Holscot.
- If you buy from Holscot, you will be buying directly from the manufacturer, based in the UK, not an agent or intermediary.
- Access to Holscot proprietary in-house manufacturing techniques and expert engineers.
- Holscot is a world leader in providing Fluoropolymer solutions, with more than 50 years experience supplying customers worldwide
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