芳綸纖維(kevlar)

1、芳綸纖維（ kevlar ）Aramid fiberAramid fiber is called "p-polyphenyl two benzoyl two of benzene amine, English Aramid fiber (DuPont Co brand name Kevlar Kevlar), is a new type of high-tech synthetic fiber, has excellent properties of ultra high strength, high modulus and high temperature resistance,

2、acid resistance and alkali resistance, light weight, the strength of steel wire 5 6 times the modulus of steel wire or glass fiber is 2 3 times, 2 times the toughness of steel wire, steel wire and the weight is only about 1/5, does not decomposeat a temperature of 560 degrees, and does not melt. It

3、has good insulation and anti-aging properties, and has a long life cycle. The discovery of aramid fiber is considered as a very important historical process in the field of materials.1. introductionAramid fiber is an important material for national defense, in order to meet the needs of modern war,

4、at present, the developed countries such as the US and Britain's bulletproof vests are made of Kevlar aramid fiber, lightweight body armor, helmets, effectively improve the army's rapid response capability and lethality. In the Gulf War, American and French aircraft made extensive use of Kev

5、lar composites. In addition to military applications, it has been widely used in many fields, such as aerospace, aviation, mechanical and electrical, construction, automobile, sporting goods and other aspects of the national economy. In aviation, aerospace, aramid due to light weight and high streng

6、th, saving fuel amount, according to foreigninformation, during the launch of spacecraft, each to reduce the weight of 1 kg, as a meansof reducing the cost of $1 million. In addition, the rapid development of science and technology is opening up more new civilian space for aramid. As report goes，At

7、present, aramid products are used in bulletproof vests, helmets and other accounts for 7 8%, aerospace materials, sports materials accounted for about 40%; tyre material, conveyor belt material etc. about 20%, there are about 13%high strength rope etc.2. classificationAramid fiber is mainly divided

8、into two types, para aramid fiber (PPTA) and meta aramid fiber (PMIA), since 1960s by DuPont (DuPont) company has successfully developed the aramid fiber and the first industry, in the past 30 years, aramid fiber has a history by military strategy supplies to the civilian goods transfer, prices also

9、 fell by nearly half. Now, foreign aramid fiber, whether it is R & D level or large-scale production, is maturing. Aramid fiber develops fastest in the field of aramid fiber production, mainly in Japan and the United States and europe. Such as DuPont Kevlar fiber, Holland AKZO NOBEL (Akzo Nobel)

10、 (the companyhas with the merger of Twaron fiber, Teijin) Japan Teijin companyTechnora and Russia's Terlon fiber fiber. The varieties of aramid fiber are Nomex, Conex, Fenelon fiber and so on. The United States DuPont pioneer of aramid fiber development, they both in the research and development

11、 of new products, production scale, or in the market share is the world first-class level, only their production of Kevlar fiber, thereare Kevlar 49, Kevlar 29 and more than 10 grades, each grade and several ten specifications the product. DuPont Co announced last year that it will expand production

12、 capacity of Kevlar fiber, which is expected to be completed by the end of this year.Hearst, Teijin aramid production enterprises also have expansion or not resigned to playing second fiddle, combined, and actively explore the market, hoping to become a force in the sunrise industry.The German Acord

13、is company recently developed a high-performance ultra-fine para aramid (Twaron) products, it is not burning, not melting, and high strength and great Hangzhou cutting ability, mainly can be used for a variety of textile and garment production equipment coating and non coating fabric, knitted fabric

14、 and needle felt both high temperature and anti cutting the. Twaron superfine filament fineness only for occupation safety clothing 60%commonly used aramid fiber, with its weaving gloves and the anti cutting ability of l0%, production of woven fabrics and knitted products with it, feel softer, more

15、comfortable to use. Twaron anti cutting gloves mainly used in automobile manufacturing industry, glass industry and metal parts production factory, production activities but also for the forest industry support, to provide anti sabotage equipment such as public transport industry. The use of flame r

16、etardancy and heat resistance of Twaron, can provide protective suits and carpet and other equipment for the fire brigade, as well as casting, high temperature furnaces, glass factory operations department to provide heat fire service, as well as the production of aircraft seat fire retardant coatin

17、g material. With thishigh-performance fiber, but also to create automotive tires, cooling hoses, V belt and other parts, optical fiber cables and bulletproof vests and other protective equipment, but also in place of asbestos friction materials and sealing materials.According to statistics of releva

18、nt departments, the world total demand of aramid fiber was 360 thousand tons / year in 2001, and it will reach 500 thousand tons / year in 2005. Demand for aramid fiber is on the increase,Aramid fiber, as a new high-performance fiber, has entered a period of rapid development.Compared with the boomi

19、ng of overseas aramid fiber industry, the localization of aramid fiber has just started. The aramid fiber in China started late in the development of foreign companies, blockade of the core technology monopoly and other reasons, the aramid fiber in China's technical level, product quality and pr

20、oduction capacity with the developed countries there is a certain gap. It is reported that in recent years, the rapid development of China's electronics, construction and tire industry, making China's aramid fiber consumption increased rapidly. China's aramid fiber made so difficult for

21、two reasons: first, the production of technical bottlenecks difficult to break; and the other is that most of the raw materials need to import, especially domestic solvents can not pass. But precisely because it is a new thing in China, the market is far from saturated, and it is worth our attention

22、 and development. At present, the development of aramid fiber production in China has been mentioned in the schedule, aramid fiber was included in the State encourages the development ofhigh tech products, the government will also "aramid fiber in engineering tire, synchronous belt in the devel

23、opment of application technology" as China's "fifteen" rubber industry major research and industrialization project. Especially in the development and production of aromatic amides in the production line, China has made a certain progress.Two. Fire retardant aramid fiber 1313Arami

24、d 1313 was first proposed by the American DuPont Co successfully developed, and in 1967 achieved industrial production, the product is registered as a Nomex&reg (Nomex).This is a soft, fluffy, shiny white slender fibers, as with the general appearance of chemical fiber,But they are more than one

25、, with extraordinary features":1. lasting thermal stability.The characteristics of Aramid 1313 is the most outstanding high temperature resistant performance is good, can be used in the high temperature of 220 DEG C without aging long-term, the effectiveness of the electric and mechanical perfo

26、rmance can be maintained for 10 years, and excellent dimensional stability, thermal shrinkage at 250 degrees around the rate of only 1%, a short time exposure to 300 DEG C high temperature will not shrink, embrittlement, softening or melting, only the strongXiacai temperature over 370 DEG to 400 DEG

27、 C to decompose carbide, such a high thermal stability in the present is the unique temperature resistant organic fiber.2., excellent flame retardancyWe know that the percentage of oxygen required for combustion of materials in the air is called the limiting oxygen index, and the greater the limitin

28、g oxygen index, the better the flame retardancy. Generally, the oxygen content in air is 21%, while the limit oxygen index of aramid fiber 1313 is greater than 28%. It belongs to nonflammable fiber, so it does not burn in air, nor does it support combustion and has self extinguishing. The inherent p

29、roperty of the molecular structure makesAramid 1313 permanent flame retardant, so it has the nameof "fire retardant fiber".3. excellent electrical insulation.Aramid 1313 low dielectric constant, dielectric strength inherent to maintain excellent electrical insulation are in high temperatur

30、e, low temperature and high humidity conditions, the preparation of the paper insulation breakdown voltage can reach 100 thousand volts / L, is the best insulating materials globally recognized.4. outstanding chemical stabilityAramid 1313 is a linear macromolecule composed of aromatic groups connect

31、ed by amide bonds,Hydrogen bonds in two planes are arranged in a three-dimensional structure, the strong hydrogen bonding makes its chemical structure exceptionally stable, resistant to most high concentrated inorganic acid and other chemical corrosion,anti hydrolysis and steam corrosion.5. excellen

32、t mechanical characteristicsAramid 1313 flexible polymer materials, low stiffness and high elongation characteristics that have the same with ordinary fiber spinnability, can be processed into a variety of conventional textile fabrics or non-woven fabrics, and wear and tear resistance, the scope is

33、very extensive. Super radiation resistance.Aramid fiber 1313 is resistant to alpha, beta, square and ultraviolet ray radiation. With 50Kv rays of 100 hours radiation, the fiber strength remained the original 73%, while the polyester or nylon became powder. The performance of special chemical structu

34、re and stable with aramid fiber 1313 excellent, through the comprehensive utilization of these characteristics, a series of new features and new products are constantly developed, applied more and more widely, more and more high popularity.6. special protective clothingAramid 1313 fabric does not bu

35、rn, does not drip, does not smoke whenit is fire, and has excellent fireproof effect. Especially in the high temperature of 900-1500 DEGC when it encountered, cloth quickly carbonization and thickening, forming unique insulation barrier that protects the wearer to escape. If a small amount of antist

36、aticfiber or aramid fiber 1414 is added,the cloth can be effectively prevented from cracking, and the hazards of lightning, arc, static electricity,flame, etc. canbe avoided.With Aramid 1313 colored fibers can be made a flight suit, defense combat uniforms, fire fighting clothing and furnace work cl

37、othes, work clothes, all over welding and anti radiation clothing, chemical protective clothing, high shielding clothing and other special protective clothing, used in aviation, aerospace, military, fire protection, petrochemical, electrical, gas, metallurgy, car etc. In addition, in developed count

38、ries, such as flame retardant pajamas aramid fabric is widely used as a hotel, household textiles, fire rescue channel decor, ironing board, kitchen gloves and protective covering old children.7. high temperature filter materialAramid fiber 1313 has high temperature resistance, dimensional stability

39、 and chemical resistance, which makes it dominant in the field of high temperature filter materials. Aramid fiber filter material widely used in chemical plants, thermal power plants, carbon black plants, cement plants, lime plants, coking plant, metallurgical plant, asphalt plant, paint factory, el

40、ectric arc furnace, oil boiler, incinerator flue temperature and hot air filter, which can effectively remove dust, but also can resist the harmful smoke chemical erosion, and recovery contribute to the precious metal.8. honeycomb structure materialUse of Aramid 1313 paper making materials Structure

41、 Bionic multi-layer honeycomb structure plate, with outstandingstrength / weight ratio and stiffness / weight ratio (about 9 times of steel), its light weight, impact resistance, flame resistance and insulation, corrosion resistance to aging and good penetration characteristics of electromagnetic wa

42、ve, suitable for production aircraft, missiles and satellite broadband wave transparent materials and large secondary stress components (such as wings, fairing, cabin lining board, door, floor, wall and cargo etc.),Also suitable for making yachts, rowing, high-speed trains and other high performance

43、 requirements of the sandwich structure.Three, bulletproof fiber - aramid 1414Almost identical with the invention of Aramid 1313, DuPont Co developed another high-performance synthetic fiber aramid fiber 1414 in the late 60s of the last century, and its products first came out in 1972, named Kevlar&

44、amp;reg. (Kevera).A metallic liquid silk with a golden appearance and a shiny appearance of 1414. It is actually a liquid crystalline polymer composed of rigid molecules. Because of its highly molecular chain length orientation, and has a strong inter chain binding force, thus giving the fibers unpr

45、ecedented high strength, high modulus and high temperature resistance.The discovery of aramid 1414 is considered an important milestone in the development of the material field. Aramid fiber 1414 has a very high strength, greater than 28 grams / denier, is 56 times the quality of steel, modulus is 2

46、3 times of steel or glass fiber, toughness is 2 times the steel, while the weight of only 1/5 of steel. (aramid fiber 1414's strength and toughness also make it difficult to cut and process, requiring expensive special tools).Aramid fiber 1414 continuous use, temperature range is very wide, in -

47、196 to 204 degrees Celsius range can long-term normal operation. Under the temperature of 150 DEGC contraction rate was 0, in the high temperature of 560 DEG C without decomposition is not melting, heat resistance of nylon 1313 in Shengfang, and has good corrosion resistance and insulation, the life

48、 cycle is very long, so it won "synthetic wire" in the world.Aramid fiber 1414 was first used in frontier areas such as national defense and military affairs. In order to meet the needs of modern war and anti-terrorism,The United States, Russia, Britain, Germany, France, Israel, Italy and

49、many other countries of the police body armor, bulletproof helmet, stab resistant clothing, EOD suits, high strength body, parachute, bulletproof armor plate are used a lot of aramid fiber 1414. In a bulletproof vest, the aramid fiber has high strength, good toughness and weaving, the bullet impact

50、energy absorption and dispersion transfer to other fabrics to avoid "blunt", thus remarkable protective effect.The lightweight of Kevlar bullet proof vests and helmets effectively improves the ability of rapid response and protection of the army.Now, in addition to the military field, has

51、1414 aramid fiber material as a kind of high science and technology has been widely used in aerospace, mechanical and electrical, construction, automotive, marine products, sporting goods and other aspects of the national economy.In aerospace, Kevlar fiber reinforced resin composites are used as str

52、uctural materials for aerospace, rocket and aircraft to reduce weight, increase payload, and save large amounts of power fuel. Such as Boeing aircraft shell, interior decoration and seats and other successful use of aramid 1414 material, reducing the weight by 30%.Aramid fiber is the best tire cord

53、fiber because of its small proportion, high strength, good heat resistance and good adhesion to rubber 1414. Aramid cord can reduce tire thin, reduce weight, easy heat dissipation, reduce the deformation, reduce rolling resistance, enhance the performance of high-speed operation, so that the service life of the tire is extended accordingly, and prick resistant performance is greatly improved,Its strong and tough features