Views: 20 Author: Site Editor Publish Time: 2021-05-31 Origin: Site
01 peek
Peek, the top product in engineering plastics industry
Peek is an ultra-high performance special engineering plastic developed by ICI in 1978. Because peek is an aromatic crystalline thermoplastic polymer material, its melting point is 334 ℃, which has high mechanical strength, high temperature resistance, impact resistance, flame retardant, acid and alkali resistance, hydrolysis resistance, wear resistance, fatigue resistance, radiation resistance and excellent electrical properties, In most cases, it can replace metals, alloys, ceramics and other materials. Although it is a kind of compound material, it does not produce non-toxic gas when burning, so its application field has been rapidly expanded in today's advocating green environmental protection design.
Molecular structure of PEEK
02 Characteristics of PEEK
(1) High temperature resistance: PEEK has high glass transition temperature (TG = 143 ℃) and melting point (TM = 343 ℃), and its load hot deformation temperature is up to 316 ℃, long-term service temperature is 260 ℃, and instantaneous service temperature is up to 300 ℃.
(2) Self lubrication: PEEK has good sliding characteristics, which is suitable for the occasions with strict requirements of low friction coefficient and wear resistance, especially the peek modified with carbon fiber, graphite and PTFE has excellent wear resistance.
(3) Corrosion resistance: except for concentrated sulfuric acid, peek is insoluble in any solvent and has high chemical stability.
(4) Flame retardant: PEEK has self extinguishing property, even without any flame retardant, it can reach 94V-0 level of UL standard.
(5) Processability: due to its good high temperature fluidity and high thermal decomposition temperature, peek can be processed in a variety of ways, such as injection molding, extrusion molding, molding and melt spinning.
(6) Mechanical properties: PEEK has good toughness and rigidity, and it has excellent fatigue resistance comparable with alloy materials.
(7) Electrical properties: PEEK has high volume resistivity and surface resistivity, can withstand AC potential field strength of various frequencies in a wide temperature range and environmental changes, and maintain good insulation performance.
(8) Hydrolysis resistance: the resin and its composites are not affected by the chemistry of water and high-pressure steam, and can be used continuously under high temperature and high-pressure steam or water environment to maintain good mechanical properties.
(9) Weatherability: excellent weatherability, polymer can be used to manufacture components with strict working environment requirements or frequent sterilization resistance.
Comparison of PEEK and several typical high temperature resistant plastics
02 Preparation of PEEK
The synthesis of PEEK is based on 4,4-difluorodibenzophenone, hydroquinone and sodium carbonate as raw materials, diphenyl sulfone as solvent, under the protection of nitrogen, when the temperature is gradually raised to close to the melting point of polymer (320 ℃). The reaction formula is as follows:
The reaction formula of PEEK synthesis
The cost of PEEK mainly depends on the high purity monomer 4,4-difluorobenzone. There are many synthetic methods, including condensation of benzene series compounds, halogen exchange, catalytic alkylation, oxidation of dichloroethylene, Friedel crafts alkylation and diazotization. The first four methods have the disadvantages of low reaction yield, high content of isomers and other impurities, complex refining process and high production cost.
At present, the main production methods are Friedel crafts alkylation and diazotization. Friedel crafts alkylation has the advantages of easy to obtain raw materials, short synthetic route, high yield and low production cost. The reaction formula is as follows:
The PEEK reaction was synthesized by Fowler alkylation
04 Production process of PEEK
There are two synthetic routes of PEEK: nucleophilic substitution and electrophilic substitution. Because of the disadvantages of electrophilic substitution route, such as easy branching of products, large amount of catalyst and solvent and unfriendly environment, nucleophilic substitution route is generally used in the world. There are only two countries with PEEK production process, China and UK. In most foreign countries, the raw material of PEEK resin is prepared by wiggs process, while in China, the process of Jilin University is mainly used.
05 Modification of PEEK
In recent years, the modification of PEEK has become one of the research hotspots at home and abroad. The main methods include Fiber Reinforced PEEK, particle filled peek, peek surface modification, blending with polymer and so on. This can not only reduce the cost of products, but also reduce the cost of products, It can also improve the processing performance and service performance of peek.
06 Application of PEEK
Peek materials have been widely used in automobile, military, medical, aviation, electrical and other industries for decades. However, the relatively high price has restricted its penetration into the general civil market for a long time. At present, it is mainly used in aerospace, high-end industry and medical fields.
Aerospace
Peek can replace aluminum and other metal materials to make aircraft parts, which can reduce weight by up to 70% compared with metal and improve fuel efficiency. At present, Boeing, Airbus and other companies have adopted a large number of PEEK materials.
medical care
Peek has the advantages of non-toxic, light weight, corrosion resistance and excellent biocompatibility, so it is a potential biomaterial for prosthesis. It is used for intervertebral fusion cage, medical catheter, bone, etc.
energy
Peek is specially used in high temperature, high pressure and chemical corrosive environment, which can expand the scope of oil and gas exploration, and can be used to manufacture annular and reticular valves of hydrogen compressor and LPG compressor in large petrochemical production line. In addition, peek can also be used for nuclear power components.
automobile
Peek has excellent mechanical properties, excellent chemical corrosion resistance and good wear resistance to automotive working fluid. It is widely used in automotive gears, vacuum pumps, clutches, valve cones, etc. to improve fuel efficiency and durability.
Food and beverage industry
Peek can be used for food processing, storage, cooking equipment parts and water, beverage delivery, storage equipment, such as pipes, valves, containers, etc.
Electronic and electrical
Peek is an ideal electrical insulator with excellent electrical performance. It can maintain good electrical insulation in harsh environment such as high temperature, high voltage and high humidity. It is used to manufacture wafer carriers, insulating films, printed circuit boards, high temperature connectors and various electrical connectors. Peek film can be used in micro loudspeaker diaphragm, 5g RF antenna substrate, etc.
Peek application demonstration
Automobile bearing
Artificial bone
Space
Gear
Peek future market demand and forecast
Since it was developed by ICI in 1978, peek has been regarded as an important strategic defense material by all countries. Since taking over from Victrex company, it has grown continuously at an annual growth rate of about 15% since it was applied in civil high-tech field.
At present, Europe is still the world's largest peek trading market. Compared with developing countries, the demand of peek in western developed countries is still dominant. Peek resin will be widely used in automotive industry, aircraft manufacturing, electronics, industrial manufacturing, medical and other fields.
It is estimated that the demand of PEEK is expected to develop rapidly in the next five years. With people's understanding of PEEK as an engineering plastic and the expanding demand of developing countries for this plastic, China, India, Southeast Asia and other markets are expected to become the main driving forces for the growth of global peek demand in the next few years.
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