PLASTICS
High-performance plastics
The so-called high-performance plastics are primarily Engineering plasticsso Polymerswhich are characterised by their mechanical, electrical and thermal properties. They are not so much visually or haptically appealing as they are for purely technical applications thought.
The distinction between high-performance plastics and engineering plastics is generally made via the Continuous operating temperature. Technical thermoplastics can usually up to a good 130°C, corresponding Thermosets up to 150°C can be used permanently.
High-performance plastics on the other hand can Temperatures of over 150°C permanently. Seen in this light, these materials could therefore also be described as High-temperature plastics can be labelled as such. However, these materials can withstand much more than just high operating temperatures. Some can also withstand cryogenic conditions with temperatures below minus 200°Cothers show a High resistance to chemicals, radioactive radiation or others Environmental influences on.
High-performance plastics can Extremely wear-resistant, Highly pure or Particularly electrically insulating be.
POLYTRON Kunststofftechnik offers high-performance plastics from the following material groups for different requirements and application conditions:
Polyimides
Depending on the type, polyimides are amorphous or semi-crystalline plastics with a generally relatively high continuous operating temperature of over 200°C.
The so-called imide group, consisting of an aromatic monomer unit, nitrogen and two carbonyl groups, which all polyimides have in their molecular structure, gives polyimides their name and is responsible for their good thermal properties.
Main features
- Good thermal properties
- High wear resistance (except PEI)
- Heat deflection temperature up to 400°C
Purely aromatic polyimides form a more or less cross-linked structure and are therefore de facto thermosetting. However, modifications in the molecular chain make it possible to produce thermoplastically processable polyimides. In this respect, polyimides can be divided into thermosetting polyimides, which are particularly resistant to high temperatures, and thermoplastic polyimides, which are easier to process.
In principle, various thermoplastic and thermosetting polyimides are available with different fillers and modifications.
Polysulphides and sulphones
Polysulphides and polysulphones are high-performance plastics whose aromatic monomer units are linked to each other via sulphur bridges.
The amorphous polyarylsulfones include polysulfone (PSU), polyethersulfone (PES) and polyphenylene sulfone (PPSU); among the polyarylsulfides, only the generally semi-crystalline polyphenylene sulfide (PPS) is of technical importance. All of these high-performance plastics have a relatively high mechanical strength combined with good temperature resistance and are considered food-compatible.
Main features
- Good mechanical strength
- High dimensional stability
- Heat deflection temperature up to over 200°C.
The amorphous polyarylsulfones (PSU, PES, PPSU) also exhibit relatively good transparency. Although these high-performance plastics are not completely transparent but slightly yellow to reddish in colour, they have a comparatively good light transmission of 75 to 85%. Compared to other transparent plastics (PMMA or PC), however, they have a significantly higher temperature resistance.
Polyaryletherketones (PEEK, PEK, PEKEKK ...)
Polyaryletherketones (PAEK) are semi-crystalline high-performance polymers that are superior to most plastics in terms of temperature and media resistance.
PAEKs contain ether and ketone groups in the polymer chain. The proportion of ketone groups in relation to the ether groups determines the melting and glass transition temperature of the different PAEKs and therefore influences the mechanical strength under the influence of temperature in particular. In principle, different combinations of ether and ketone groups and thus different melting and glass transition temperatures are possible. However, the best known form is PEEK. The continuous service temperature of all PAEKs is 260°C.
PAEKs exhibit high strength and rigidity and are resistant to almost all organic and inorganic chemicals and hydrolysis-resistant up to 260°. They are considered to be highly pure, hardly outgas in a vacuum and are classified as physiologically harmless and therefore suitable for contact with humans. Food suitable. They also fulfil the highest requirements for biocompatibility and can be used in Medical and pharmaceutical applications can be used. PAEKs are self-extinguishing and produce little smoke in the event of fire. The electrical and dielectric properties are excellent even at high temperatures.
Main features
- Continuous operating temperature 250°C
- High mechanical strength and rigidity
- highly pure and physiologically harmless.
Due to their properties, PAEKs are used for a wide variety of thermally stressed components in all conceivable applications.
Fluoroplastics
Fluoroplastics are semi-crystalline thermoplastics made from perfluorinated monomers. In these plastics, the hydrogen atoms of the carbon main chains are completely or partially replaced by fluorine atoms. These fluorine bonds are relatively stable, meaning that fluoroplastics are highly resistant to chemicals and temperatures.
Fluoroplastics have a relatively high degree of crystallisation and a very high density for unfilled plastics of up to 2.2 g/cm³. Fluoropolymers also have good electrical and dielectric properties.
Fluoroplastics include the non-fusible polytetrafluoroethylene (PTFE) with its modifications, better known as Teflon®, and the thermoplastically processable polyvinylidene fluoride (PVDF). Both together are the most important representatives of this group, which also includes a large number of other thermoplastic fluorine compounds.