PAEK full name: Polyaryletherketones known as PAEK is a class of high-performance engineering plastics family, currently known PAEK polymers there are more than 300 kinds of polymers, and the most famous representatives are PEEK, PEK, PEKK Polymer.
Among all the polymers available in the PAEK family, PEEK is the most widely used one in various applications. The given molecule forms a ketone group and two ether groups; It has the rigidity of a ketone and the ability to rotate around the ether link. PEEK is synthesized from alkylation and aromatic nucleophilic substitution of bisphenolates that affords the material flexibility and strong chemical and oxidative resistance; it has a high use temperature of over 300°C.
The linear and regular arrangement of the PEEK backbone, also makes the material rigid and capable of being crystalline, which produces a strong and hard bulk material. It also makes the PEEK material lighter compared to metals and therefore it has a greater specific strength. The degree of crystallinity that exists in PEEK defines its mechanical characteristics including strength or stiffness, on the other hand, the amorphous phase of PEEK defines ductility and fatigue behavior.
The second material that can be mentioned in the list of PAEK materials is PEKK, which has a different molecular structure being an amorphous material with two ketone groups and one ether group in the repeating unit. It confers on PEKK greater thermal stability and chemical resistance besides the higher glass transition and melting temperatures to the material than PEEK. PEKK’s ketone bonds are more flexible as compared to that of PEEK and due to this reason the flexibility of the polymer in PEKK is high.
PEEK: Usually it is produced in a milky white or light yellow color, and possesses a high transmittance or light transmission when it is used in the form of a film or a sheet.
PEKK: Often the color is darker, for example, light brown or dark brown and its translucency is rather low. Because of high crystallinity, PEKK may look slightly different and more turbid in some cases as compared to other similar materials. ”
PEEK: It has a smooth surface and it can be glossy after processing thus good for use where aesthetics is key.
PEKK: There is still a marginally lower surface finish to PEEK and the polished surface may have a rough appearance once processed.
PEEK: it is used in the form of granules or films for injection molding and extrusion molding.
PEKK: Also available in the form of granules but because of its flow characteristics it may possess different physical properties after molding like higher hardness.
Mechanical strength:
The tensile and compressive strength of PEEK is slightly higher than that of PEKK, so it is recommended for high-load applications. Despite being somewhat inferior to PEKE, there are good prospects for the material’s toughness and strength in some applications.
Crystallinity:
PEEK’s crystallinity is much higher and it is often referred to as a semi-crystalline polymer. The crystallinity index of PEKK ranged between 45 and 50 percent while that of PEEK is between 43 and 30 percent hence depicting PEKK as relatively more amorphous.
Surface smoothness:
Compared with other materials, PEEK has a smooth surface, and could get a higher surface gloss after processing. PEKK has slightly lower surface quality and can look more like it is rugged after being processed.
Surface smoothness:
Compared with other materials, PEEK has a smooth surface, and could get a higher surface gloss after processing. PEKK has slightly lower surface quality and can look more like it is rugged after being processed.
Chemical resistance:
It is a very chemically resistant material and therefore PEEK is qualified to the NORSOK M-710 standard of the oil and gas industry. PEKK also has good chemical stability but, here once again, PEEK is more trustworthy in some of the very highly corrosive situations.
Water resistance:
Water resistance: As for the water resistance, both PEEK and PEKK materials have very good performance and they can stay in the water for a long time.
Electrical insulation:
It is reported that PEKK has good electrical insulation properties; it is pointed out that the limiting oxygen index of the unreinforced grade can achieve 36% and UL94 V-0 level when no flame retardant is added.
Radiation resistance:
PEKK has relatively high radiation resistance The radiation resistance of each of the polyether ketone coatings can be indicated as very good.
High-temperature resistance:
PEEK has a glass transition temperature (Tg) equal to 143°C, and the melting point of this polymeric is equal to 343°C. The Tg of PEKK is 160-165°C and its Tm is between 305 and 355°C as these depend on the formulation placed in use. This means that in high-temperature environments, PEKK undergoes lesser thermal degradation as compared to other similar thermoplastics.
Heat deformation temperature:
PEKK has better mechanical properties, and its heat deformation temperature is much higher than that of PEEK; it is 160°C higher than PEEK‘s 145°C.
Processing temperature:
The processing temperature of PEEK is about 385°C, while PEKK has a relatively low processing temperature of about 375°C. This means that PEKK can be processed via different methods and it has a wide process window.
| Material | Advantages | Disadvantages |
| PEEK | Cost-effectiveness: Suitable for small and large-scale production with good cost-efficiency. | Cost: Relatively expensive, with a market price of around €300-350/500g. |
| Flexibility and modifiability: Can be customized according to needs, suitable for medical devices. | Environmental impact: Production and disposal have environmental impact, requiring sustainable management. | |
| Chemical resistance: Strong resistance to a variety of chemicals, suitable for harsh environments. | ||
| Precision and consistency: Maintains tight engineering tolerances, ensuring component consistency. | ||
| Dental applications: Excellent wear resistance and compressive strength, suitable for dental applications. | ||
| Mechanical strength: Maintains mechanical strength and dimensional stability at high temperatures. | ||
| Machinability: Can be precisely machined into complex shapes, suitable for a wide range of industrial applications. | ||
| PEKK | Excellent chemical resistance: Stronger resistance to a wider range of chemicals. | Cost: Often more expensive than PEEK (around €350-400/500g). |
| High wear resistance: Better wear resistance and lower coefficient of friction, suitable for high-stress applications. | Processing challenges: High powder cost, precise control of 3D printing parameters required. | |
| Multifunctional processability: Can be processed by various methods such as injection molding, extrusion, and 3D printing. | ||
| Enhanced thermal performance: Provides higher thermal conductivity and performance, especially when carbon fiber reinforced. |
| Medical properties | BIOPEEK | BIOPEKK |
| Antibacterial properties | PEEK by its nature is not antimicrobial however it can be made antimicrobial through reinforcements with antimicrobial reinforcements or coatings. | The unique structure of PEKK makes it possible to show better antimicrobial activity in some cases, particularly when combined with antimicrobial substances. |
| Biocompatibility | PEEK has very good biocompatibility and can be used in medical implants, but their antimicrobial activity should receive further process. | PEKK is quite acceptable and it is shown that it possesses acceptable antimicrobial characteristics for long-term implant application. |
| Surface treatment | PEEK can however be made to undergo physical or chemical change on the surface to enhance the inherent antimicrobial properties such as coating of PEEK. | PEKK other surface treatment techniques such as plasma and UV treatments can enhance the antimicrobial characteristics while the surface modification impact in this case is greater due to the lower crystallinity of the polymer. |
| Application examples | PEEK is employed in spinal implants, joint replacement, and the like; however, more steps are needed to enhance the antimicrobial characteristic. | PEKK is applied to dental applications and craniomaxillofacial reconstruction; the antimicrobial procedure can significantly minimize the infection rate. |
Therefore, PEEK is a special material with specific characteristics such as high temperature resistance, excellent chemical resistance, good mechanical properties, low wear performance and biopeek, making it suitable for a variety of uses in competitive industries such as aerospace, automotive, electronics and medical devices. Compared with PEEK, it varies in different performance aspects, which still depends on the demand for the product.
If you still have doubts about paek, peek, pekk, please contact us.
Zhejiang Baowei Industrial invested 15 million yuan in the newly built PEEK application technology research and development center, which has been put into use. With the help of this research and development center, our technical personnel can provide many technical services for the PEEK industry, mainly including:
