Polyether ether ketone (English poly-ether-ether-ketone, referred to as PEEK) is a polymer composed of repeating units containing one ketone bond and two ether bonds in the main chain structure, and is a special polymer material. It has high temperature resistance, chemical corrosion resistance and other physical and chemical properties. It is a type of semi-crystalline polymer material. It has a melting point of 334 ° C, a softening point of 168 ° C, and a tensile strength of 132 to 148 MPa. It can be compounded with glass fiber or carbon fiber to make reinforcing material. Generally, a type of polyarylene ether polymer obtained by condensation with an aromatic dihydric phenol is used. At present, the domestic production of PEEK plate rods has been relatively mature, the main producing areas are Ningbo, Zhejiang, Suzhou, Jiangsu, and so on. The British Victrex company and the American Amoco company have PEEK products, as well as the VESTAKEEP powder products of the German Evonik company.
Physical and chemical characteristics:
PEEK plastic materials have excellent dimensional stability characteristics, which is important for some applications. Changes in environmental conditions such as temperature and humidity have little effect on the size of PEEK parts, which can meet the requirements for use under high working conditions where dimensional accuracy is required.
1 PEEK plastic raw material injection molding has a small shrinkage rate, which is very beneficial for controlling the dimensional tolerance range of PEEK injection molded parts, making the dimensional accuracy of PEEK parts much higher than that of general-purpose plastics;
2 The coefficient of thermal expansion is small. As the temperature changes (which can be caused by changes in ambient temperature or frictional heat generation during operation), the size of the PEEK parts changes little;
3 Good dimensional stability. The dimensional stability of plastic refers to the dimensional stability of engineering plastic products during use or storage. This change in size is mainly due to the increase in the activation energy of the polymer molecules, which makes the segment have a certain kind of Degree of curl
4 PEEK has outstanding heat resistance and hydrolysis resistance, and its water absorption is very low under high temperature and high humidity environment. There will be no obvious change in the size of general plastics such as nylon due to water absorption.
5 Peeling resistance: PEEK has good peeling resistance, so it can be made into thin or electromagnetic wires and can be used under severe conditions.
6 Fatigue resistance: PEEK has the best fatigue resistance among all resins.
7 Radiation resistance: The ability to withstand high radiation is very strong, exceeding the best radiation resistance polystyrene in general resins. It can be made into a high performance that can maintain good insulation ability even when γ irradiation dose reaches 1100Mrad.
8 Mechanical characteristics: PEEK has rigidity and flexibility, especially the fatigue resistance under alternating stress is very outstanding, and it can be comparable with alloy materials.
9 Self-lubricating: PEEK has excellent sliding properties, suitable for occasions where low friction coefficient and abrasion resistance are strictly required, especially the sliding grade PEEK modified with carbon fiber, graphite, and PTFE. superior.
10 Corrosion resistance: In addition to concentrated sulfuric acid, PEEK is insoluble in any solvents and strong acids and alkalis, and is resistant to hydrolysis and has high chemical stability.
11 Flame retardancy: PEEK has self-extinguishing property, even without any flame retardant, it can reach UL standard 94V-0.
12 Ease of processing: Because PEEK has the characteristics of good high-temperature fluidity and high thermal decomposition temperature, a variety of processing methods can be used: injection molding, extrusion molding, compression molding, and melt spinning.
Density 1.265 (amorphous) ～
1.320 (crystalline) g / cm3
Impact strength (notch) 60 ～ 80J / m
Elongation at break
Water absorption
Volume resistivity 1016Ω · cm
Bending strength
Dielectric constant 3.2 ～ 3.3
Tensile strength
Flame retardancy (UL94) V-0.
application:
Because PEEK has excellent comprehensive properties, it can replace traditional materials such as metals and ceramics in many special fields. The high temperature resistance, self-lubrication, wear resistance and fatigue resistance of this plastic make it one of the most popular high-performance engineering plastics today. It is mainly used in the aerospace, automotive industry, electronics, electrical and medical equipment.
(1) Aerospace: PEEK can be processed into a variety of high-precision aircraft parts. Due to its good hydrolysis resistance, corrosion resistance and flame retardancy, it can be processed into aircraft internal / external components and rocket engines. Many parts.
(2) Automotive manufacturing: PEEK has been successfully used in the automotive industry. Due to its good friction resistance, it can replace metal (including stainless steel, titanium) to make engine covers, automotive bearings, seals and brake pads. Wait.
(3) Industrial field: PEEK has good mechanical properties, high temperature resistance, abrasion resistance, and high pressure resistance. It is commonly used to manufacture compressor valve plates, piston rings, seals, etc.
(4) Medical equipment: PEEK can withstand 3000 cycles of autoclaving at 134 ° C. This feature meets the requirements of sterilization, the manufacture of surgical and dental equipment requiring repeated use, and its resistance Creep and hydrolysis resistance, it can be used to make a variety of medical equipment requiring high temperature steam sterilization. Especially important is that PEEK is non-toxic, lightweight, and corrosion-resistant, and is the closest material to human bones. Therefore, PEEK can be used instead of metal to make human bones.
(5) Insulation materials: PEEK has excellent electrical properties, and can maintain the insulation properties of PEEK under severe conditions such as high temperature and high humidity. It is an ideal electrical insulation material, especially widely used in the semiconductor industry. application.
(6) It is a new engineering plastic that can be used as high temperature resistant structural materials and electrical insulation materials, and can be compounded with glass fibers or carbon fibers to prepare reinforcing materials.
Although polyetheretherketone has many excellent properties, it is expensive, which limits its application in some fields. In addition, its impact strength is poor. In order to further improve its performance to meet the comprehensive performance and diversified needs of various fields, it can be modified by methods such as filling, blending, crosslinking, and grafting to obtain properties. More excellent PEEK plastic alloy or PEEK composite material. For example: blending PEEK with polyether can get better mechanical properties and flame retardancy; blending PEEK with PTFE makes composite materials with outstanding abrasion resistance, which can be used to manufacture sliding bearings, dynamic seal rings and other components; PEEK is filled with carbon fiber and modified to make a reinforced PEEK composite material, which can greatly improve the hardness, rigidity and dimensional stability of the material.
PEEK has outstanding high temperature and heat resistance. It can be used at 250 ℃ for a long time, and the temperature can reach 300 ℃ in an instant. It has high rigidity, dimensional stability, and small linear expansion coefficient, which is close to that of metal and aluminum. PEEK has good chemical stability. , Has strong anti-corrosion ability to acid, alkali and almost all organic solvents, at the same time has flame retardant, anti-radiation and other properties; PEEK excellent resistance to sliding wear and fretting wear, especially can be maintained at 250 ℃ High abrasion resistance and low friction factor; in addition, PEEK is easy to extrude and injection mold. With these excellent comprehensive properties, PEEK is mainly used in automotive and aviation engine cases, headlight reflectors, heat exchange parts, valve bushings, and deep sea oil field parts, machinery, petroleum, chemical, nuclear power, rail transportation, electronics and medicine It has a wide range of applications.
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