PEEK (polyether-ether-ketone) and PTFE (poly-tetra-fluoro-ethylene) are two thermoplastic materials used in various industrial applications due to theiroutstanding chemical and thermal properties. In this in-depth article, we will first introduce the physical and chemical characteristics of both materials, examine their most common uses and their strengths and weaknesses. Finally, the processing of PEEK and PTFE will be described.

Characteristics of PEEK and PTFE materials

PEEK (PolyEtherKetone) is a thermoplastic polymer known for its outstanding thermal properties, with a melting point around 343°C, and chemical properties, resisting a wide range of chemicals, including acids, bases and solvents.
The chemical formula of PEEK is (C19 H12 O3)n; this chemical formula represents the basic structure of this polymer, with ‘n’ indicating the length of the polymer chain, which may vary depending on the production process and specific applications. As evident from the chemical formulation, PEEK consists mainly of carbon atoms, making it very temperature resistant and mechanically robust, with high resistance to wear and abrasion.
PEEK has the advantage of retaining its shape and size even at high temperatures, and can also be used in medical applications due to its biocompatibility. On the other hand, it is relatively more expensive than other polymers and its processing can be more complex.

PTFE (PolyTetraFluoroEthylene) is also known by the registered trademark Teflon and is a fluoropolymer belonging to the perfluorocarbon (PFC) family; it is known for its chemical resistance, virtually impervious to a wide range of corrosive chemicals. It also has the lowest coefficient of friction among known materials, making it excellent for lubrication and non-stick applications.
The chemical formula of PTFE is (C2 F4)n where, again, ‘n’ represents the polymer chain consisting of repeats of the monomer unit of PTFE. The basic monomer unit of PTFE is composed of two carbon atoms (C2) and four fluorine atoms (F4) linked together by covalent bonds, which gives PTFE its exceptional chemical resistance. It also resists high temperatures well, with a melting point around 327°C.
PTFE is an excellent electrical insulator and is used in electrical and electronic applications and retains its properties at extremely low and high temperatures.
On the other hand, PTFE has a relatively low mechanical resistance compared to other materials, which limits its applications in high mechanical loads; moreover, at high temperatures, PTFE can undergo permanent deformation. Due to its non-stick nature, PTFE can be difficult to bond or bond to other materials in processing.

Typical uses of PEEK and PTFE in industry

Both PEEK and PTFE are versatile materials that are suitable for a variety of applications, particularly when a combination of chemical resistance, heat resistance, dimensional stability and other specific properties are required.
The main typical uses of PEEK include:

• components in the aerospace industry where it is used in engine parts, sealing systems, and other aircraft applications due to its light weight and thermal resistance;
• medicaldevices, especially in surgical instruments, medical imaging devices and implants due to its biocompatibility and chemical resistance;
• oil and gas industry, finding use in valve components resistant to corrosion and high pressure and temperature environments.
• components in thechemical industry, for parts that must withstand aggressive chemicals;
• automotive components, in applications such as seals, bearings, power electronics, and piping.
• design gaskets, in all industrial fields through the creation of customised gaskets based on a drawing or mould.

The main uses of PTFE include:

• non-stick coatings, being famous for being the material used in non-stick coatings for pots and pans;
• gaskets, bushings and seals, thanks to its high chemical resistance;
• pipes and valves especially for aggressive chemicals;
• electronics, in electrical insulators, cables, connectors and components because of its electrical stability;
• pharmaceutical industry, in laboratory equipment, piping and dosing systems;
• food industry, as a component in food handling and transport equipment;
• chemical industry, especially in chemical-resistant tanks, pipes and equipment.

From an economic point of view, PEEK is generally more expensive than PTFE, but the cost of polymeric materials can vary widely depending on factors such as the purity of the material and the physical form in which it is sold (granules for the production of parts, semi-finished or ready-made forms).

It is important to consider the cost of materials in the context of specific production requirements and benefits. For more than 30 years, TAFER has been helping and advising companies on the selection of the best material, basing the evaluation on a comprehensive analysis of the required performance, the specifications of the application or production chain and the target economic framework.

PEEK and PTFE processing

The processing of PEEK and PTFE requires different techniques and skills due to the differences in material properties. Both materials require care during processing due to the high temperatures involved.
TAFER specialises in the production of semi-finished products made of virgin and filled PTFE and polymeric materials such as pure and filled PEEK and is a leading company in Italy in the production of customised components with machining and injection-moulded technopolymers. To ensure the highest level of expertise and receive targeted technical advice on the optimal use of these materials, it is advisable to contact TAFER.

PEEK can be processed through:

• cutting and milling with conventional machine tools, taking care to use wear-resistant tools due to the hardness of the material;
• turning with hard cutting tools, such as carbide inserts, taking care to adjust the cutting speed to avoid overheating and deterioration of the material;
• injection moulding, particularly for the production of complex components; this process requires specialised equipment and temperatures;
• high-speed CNC machining for the production of precision parts.

PTFE processing can take place through:

• cutting and milling, being easily machined with conventional cutting tools, with no need for special coolants;
• hot injection moulding using specialised equipment. This process requires high temperatures for melting the material with effective control to prevent decomposition of PTFE at too high a temperature;
• sintering for the production of compact components by heating PTFE above its melting point and subsequent cooling.
• cold pressing, a technique rarely used because it requires considerable pressure to deform the material.

In general, PTFE is more machinable than PEEK, however, if high mechanical performance is required, PEEK may be the better choice, even if it requires more machining. To find out how our PEEK and PTFE solutions can raise the quality and efficiency of your projects, please contact TAFER: our experience is at your service to guide you to the best choice.