A Brief Guide – Properties, Production, And Processing Of PTFE
Teflon is a semi-crystalline fluoropolymer, which is also known as polytetrafluoroethylene (PTFE). PTFE is the most common fluoropolymer in recent years with significant market growth and is likely to expand even more in the future.
By 2022, worldwide PTFE earnings are predicted to exceed $7 billion, and the demand is estimated to reach 247,000 megatonnes. It is because of the growing use of polymers in electronics and chemicals and the thriving usage of polymers in solar modules and fuel cells.
What Are The Properties Of PTFE
PTFE is a semi-crystalline synthetic polymer with a carbon backbone and fluorine atoms surrounding it. It is made when tetrafluoroethylene (TFE) monomers undergo a free-radical addition polymerization response. The exceptional corrosion resistance and electrical inertness of PTFE machined parts are due to the layer of fluorine atoms, which functions as an obstacle.
The hydrophobic properties, less surface tension, and less dielectric constant of PTFE are due to its symmetrical pattern. Based on the use, it comes in granules, fine powder, or water-based diffusions.
- The density of PTFE at 23 degrees Celsius is 2.13 to 2.23 g/cm³.
- The melting point of PTFE is 325 to 335 degrees Celsius.
- The coefficient of thermal expansion of PTFE at 23 degrees Celsius is 1 to 2 E-4/K.
- The maximum service temperature of PTFE is 260 degrees Celsius.
- The thermal conductivity of PTFE at 23 degrees Celsius is 0.25 W/(m∙K).
- The specific heat capacity of PTFE at 23 degrees Celsius is 1000 J/(kg∙K).
- The flammability of PTFE is V0 UL 94 (flame retardant).
- The elastic modulus of PTFE at 23 degrees Celsius is 0.4 to 0.75 GPa.
- The elongation of PTFE at 23 degrees Celsius is 350 to 550 %.
- The yield strength of PTFE at 23 degrees Celsius is 20 to 35 MPa.
- The impact strength of PTFE at 23 degrees Celsius is 13 to 15 kJ/m²
- The dielectric constant of PTFE at 23 degrees Celsius is 2.1.
- The dielectric strength of PTFE is 20 to 48 kV/mm.
- The electrical resistivity of PTFE at 23 degrees Celsius is 1-1000 E+15 Ω∙m
Explaining Production And Processing Of PTFE
Granular, dispersion and fine powder forms of PTFE are available. Due to its high melting temperature and melt viscosity, semi-crystalline PTFE is hard to extrude and inject. As a result, PTFE processing is more like powder processing than standard plastics processing.
A water-based suspension polymerization procedure produces granular PTFE. Compression molding is frequently used to form the granular resin that remains. PTFE dispersion products are made in the same way but with the addition of dispersing agents.
Dispersion materials can be utilized for PTFE coatings or film cast into a thin film. An emulsion polymerization response generates PTFE powder. The fine powder that remains can be paste extruded into PTFE tubes, tapes, cable insulation, or utilized as a corrosion inhibitor in other polymeric substances.
Between 5 to 40% glass fibers can be added to PTFE to increase creep characteristics and common wear over time. Bronze is a popular addition used to increase continuous service temperature by improving thermal and electrical conductivity.
Hardness and wear resistance can be improved by adding carbon. These additions are suitable for O-rings and seals that need to be friction resistant and resistant to corrosion, such as those utilized in automotive applications.
What Are Different Grades Or Standards Of PTFE
There are several grades of PTFE. Thus, we have listed the different grades of PTFE.
Teflon, also known as ISO-PTFE, is a chemical and thermally resistant material. ISO-PTFE is an excellent substance for a wide range of demanding applications in the chemical, food, and pharmaceutical industries due to its extraordinarily low surface tension.
PPS GF40 PTFE SG401E65
It is a PPS & PTFE compound with 40% glass fiber reinforcement that has been carefully developed to have less coefficient of friction for applications related to low surface friction and wear.
PEEK PTFE SG201RN
It is also a PTFE & PEEK alloy grade with a relatively less coefficient of friction for usage in low surface friction and chemical resistant applications.
PEEK CF30 G PTFE SGC301E4
It is a 30% carbon-fiber enhanced PTFE and graphite-strengthened PEEK blend designed to give superior resistance to wear, low coefficient of friction, and chemical resistance.
Because of its excellent resistance to heat and corrosion, PTFE is commonly used as a non-stick coating for kitchen bowls and pans. In addition to that, these characteristics have also proven beneficial in other areas, including the chemical, automotive, and medical industries where chemical inactivity, electrical insulation, and long service life are particularly critical.