Today's KNOWLEDGE Share : PEKK, and PEEK

Today's KNOWLEDGE Share

Understanding the Differences Between PEKK, and PEEK Materials:

PEKK and PEEK are both in the Polyaryletherketone family of ultra-high performance polymers. 

Unlike PEEK, PEKK is a copolymer with a slower and highly tunable crystallization rate making it the preferred choice for additive manufacturing.

PEKK can be printed directly in either the amorphous or semi-crystalline state, or printed amorphous and crystalline in a secondary process, offering the ultimate combination in performance and processing flexibility.

   

CHEMICAL COMPOSITION AND STRUCTURE

PEKK (Polyetherketoneketone):

Structure: PEKK consists of ether (O) and ketone (C=O) linkages,with two ketone groups in the repeating unit. This structure provides high thermal stability and chemical resistance, making PEKK ideal for demanding environments.

PEAK (Polyetherketone):

Often confused with PEKK, PEAK is a general term referring to various types of polyetherketones. It includes polymers with similar structures but slight variations in the arrangement of ether and ketone groups, encompassing both PEKK and PEEK among others.

THERMAL PROPERTIES

PEKK boasts a higher glass transition temperature (Tg) and melting point compared to PEEK.

Tg typically ranges between 160°C to 165°C.

Melting point is around 340°C.

PEEK:

Tg is around 143°C.

Melting point is approximately 343°C.

MECHANICAL PROPERTIES

PEKK: The additional ketone group in PEKK increases rigidity, resulting in higher mechanical strength and stiffness.

It offers better wear resistance and a lower coefficient of friction, which is advantageous for high-stress applications.

PEEK provides an excellent balance of toughness, stiffness, and strength.

It is slightly more flexible than PEKK, which can be beneficial for applications requiring a degree of ductility.

CHEMICAL RESISTANCE

PEKK:

The more rigid structure of PEKK grants it superior chemical resistance.

It excels in resisting a wide range of chemicals, including acids, bases, and organic solvents.

PEEK is highly resistant to many chemicals, though slightly less so compared to PEKK.

Its chemical resistance is still exceptional,making it a reliable choice for harsh environments.

PROCESSING AND APPLICATIONS

PEKK can be processed using similar methods as PEEK,such as injection molding, extrusion, and 3D printing.

It is commonly used in aerospace, automotive, and medical applications where high performance is required under extreme conditions.

PEEK is widely used across various industries, including aerospace, automotive, electrical, and medical devices.It is easier to process than PEKK due to its slightly lower melting point and greater flexibility.

Additive Manufacturing and Injection Molding:

Both PEKK and PEEK have significant implications for additive manufacturing (3D printing) and injection molding.Their high-performance properties allow for the production of complex, precision parts that can withstand extreme conditions.

source:addmangroup/arkema