PEI - Replacement of PEEK,Upstart In Dielectrics

What is PEI?

Polyetherimide, referred to as PEI, is called Polyetherimide in English and has an amber appearance. It is an amorphous thermoplastic special engineering plastic that introduces flexible ether bonds (-R-O-R-) into the rigid Polyimide long-chain molecules.

PEI structure

As a thermoplastic polyimide, PEI can significantly improve the poor thermoplasticity and difficulty in processing of polyimide by introducing ether bonds (-R-O-R-) into the polymer main chain while retaining the imide ring structure. question.

Characteristics of PEI

Advantage:

High tensile strength, the strength is above 110MPa;

High flexural strength, strength above 150MPa;

Excellent thermomechanical load-bearing capacity, thermal deformation temperature greater than or equal to 200°C;

Good creep resistance and fatigue resistance;

Excellent flame retardant performance and low smoke combustion;

Has excellent dielectric and insulation properties;

Excellent dimensional stability, low thermal expansion coefficient;

High heat resistance, can be used for a long time at 170℃;

Can pass through microwaves.

Shortcoming:

Contains BPA (bisphenol A), limiting its application in infant-related products;

Notch impact sensitive;

The ability to withstand alkali is average, especially under heating conditions.

Preparation of PEI

PEI is composed of m-(or p-phenylenediamine) and 2,2'-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) in dimethylacetamide solvent. It is prepared by heating and polycondensation, powdering and imidization.

What is PEI application ?

PEI has good high temperature resistance and dimensional stability, as well as chemical resistance, flame retardancy, electrical properties, high strength, high rigidity, etc. Its superior thermal stability can be used to make high-temperature and heat-resistant devices; Mechanical properties can be enhanced and modified by adding glass fiber, carbon fiber or other fillers; these properties also make PEI widely used in high-temperature terminals, IC bases, lighting equipment, FPCB (flexible circuit boards), liquid delivery equipment, and aircraft interiors parts, medical equipment and household appliances.

Electronic and electrical industry

In the electronic and electrical industry, PEI with excellent mechanical properties can be used to manufacture many parts, such as connectors that require high dimensional stability, shells of small relays, circuit boards, etc.

PEI can also be used to manufacture fiber optic components with higher precision, such as fiber optic connectors. Using PEI instead of metal to manufacture optical fiber components can not only maintain the optimized structure of the parts, maintain more precise dimensions, simplify the assembly process, but also reduce manufacturing and assembly costs. In addition, PEI is often used as switches, bases and other parts in the instrument industry.

Automotive machinery field

It can be used for mechanical high-temperature friction parts, such as bearings, heat exchangers, carburetor covers, etc.

Aerospace field

It can be used to manufacture some internal parts of aircraft, such as rocket fuze caps, aircraft lighting equipment, etc.

Medical field

It can be used as handles, trays, clamps, prostheses, medical light reflectors and dental appliances for medical surgical instruments. It can also be used in medical equipment such as ventilators, anesthesia machines, sterilization trays, surgical guides, pipettes and laboratories. Animal cages, etc.

Household appliances field

Can be used as product packaging and microwave trays.

PEI is widely used
It is worth mentioning that PEI is considered a promising energy storage polymer dielectric material due to its good thermal and mechanical properties, low dielectric loss and excellent energy storage performance. In addition to dielectric energy storage, PEI's excellent dimensional stability, electroplatability and wave transmittance make it another huge application scenario in 5G communications.

Optical Communication

PEI materials lead the field of optical communications and are widely used in optical fiber connectors and optical components of optical transceiver modules.

First, the PEI material has good infrared penetration, with a transmittance of more than 88% in the 850-1550nm optical communication frequency band. Its high refractive index remains constant despite changes in temperature and humidity, and can withstand up to 2,000 hours. The double 85 (85℃/85% humidity) harsh test; secondly, it has excellent long-term dimensional stability, which can provide reliable optical docking for signal transmission; thirdly, it has high strength and high modulus, which can replace metal-made optical fibers. Connectors, adapters and other structural components; fourth, it has the characteristics of high dimensional stability and high strength, as well as very good weather resistance. It can be used in the field of waterproof connectors of optical fiber splitting boxes or base stations, and can meet the waterproof requirements of IP67, and Significantly improve the long-term air tightness and reliability of the product.

RF connector insulator

RF connector insulators require materials that provide good dielectric properties, low and stable dielectric loss, good mechanical properties, excellent dimensional stability for easy assembly, and reliable mass production performance. PEI materials are excellent in all the above aspects. It can meet the application requirements and has become the first choice of insulator material for RF connectors.

Filter

As an amorphous material with a high glass transition temperature, PEI material has a linear thermal expansion coefficient similar to that of aluminum alloy, excellent heat resistance and dimensional stability, long-term reliability, low and stable dielectric loss, can be electroplated, and It has the characteristics of good metal adhesion and other characteristics, and shows incomparable advantages of other plastic materials in the application of cavity filters. In addition, 5G base station antenna cavity filter units made of PEI materials can achieve weight reductions of up to 30%; and can be mass-produced through injection molding processes to maintain batch-to-batch dimensional accuracy and reduce production costs.
With the technological development of 5G, product size is reduced and accuracy and mechanical performance requirements are more stringent. The application advantages of PEI are becoming more and more obvious.

Phase shifter

In base station antennas, PEI is also widely used in phase shifters, whether it is the dielectric sheet of a dielectric phase shifter or the PCB bracket in a ring phase shifter, all benefit from the good size and performance of PEI materials in a wide temperature range. Stability of dielectric properties, low dielectric loss, high mechanical strength and excellent resilience. With the gradual commercialization of 5G base stations and the pursuit of further reducing energy consumption and costs, traditional dielectric phase shifters or ring phase shifters will have the opportunity to replace chip phase shifters and be widely used in 5G massive MIMO antennas.


PEEK that must be mentioned

PEEK appearance

PEEK, whose scientific name is Polyetheretherketone, is a polymer composed of repeating units containing one ketone bond and two ether bonds in the main chain structure. It is a special polymer material. PEEK has a beige appearance and has good processability, sliding and wear resistance, good creep resistance, very good chemical resistance, good resistance to hydrolysis and superheated steam, and high temperature radiation resistance. In addition, its thermal It has high deformation temperature and good intrinsic flame retardancy.
PEEK was first used in the aerospace field to replace aluminum, titanium and other metal materials to manufacture interior and exterior aircraft parts. Because PEEK has excellent comprehensive properties, it can now replace traditional materials such as metals and ceramics in many special fields. Its high temperature resistance, self-lubrication, wear resistance and fatigue resistance make it one of the most popular high-performance engineering plastics today.
Both are thermoplastic polymer materials. The characteristics of PEI are similar to that of PEEK. It can even be said to be the replacement of PEEK. Let us take a look at the differences between the two.