芳纶纤维（kevlar）

1、芳纶纤维（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, acid res

2、istance 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 decompose at a temperature of 560 degrees, and does not melt. It has goo

3、d 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, at pres

4、ent, the developed countries such as the US and Britains bulletproof vests are made of Kevlar aramid fiber, lightweight body armor, helmets, effectively improve the armys rapid response capability and lethality. In the Gulf War, American and French aircraft made extensive use of Kevlar composites. I

5、n 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 strength, saving fuel a

6、mount, according to foreign information, during the launch of spacecraft, each to reduce the weight of 1 kg, as a means of 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 present, aramid

7、 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 into two types

8、, 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 fell by nearl

9、y 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) (the company has

10、with the merger of Twaron fiber, Teijin) Japan Teijin company Technora and Russias 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 of new products, pro

11、duction scale, or in the market share is the world first-class level, only their production of Kevlar fiber, there are 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 capacity of Kevlar

12、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 Acordis company recently

13、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 and needle felt bot

14、h 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 comfortable to use.

15、 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 retardancy and heat

16、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 coating material. With th

17、is high-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 relevant departments, th

18、e 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 booming of overseas ara

19、mid 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 Chinas technical level, product quality and production capacity with

20、the developed countries there is a certain gap. It is reported that in recent years, the rapid development of Chinas electronics, construction and tire industry, making Chinas aramid fiber consumption increased rapidly. Chinas aramid fiber made so difficult for two reasons: first, the production of

21、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 and development. At present, the deve

22、lopment of aramid fiber production in China has been mentioned in the schedule, aramid fiber was included in the State encourages the development of high tech products, the government will also aramid fiber in engineering tire, synchronous belt in the development of application technology as Chinas

23、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 1313Aramid 1313 was first proposed by the American DuPont Co successfully d

24、eveloped, and in 1967 achieved industrial production, the product is registered as a Nomex® (Nomex). This is a soft, fluffy, shiny white slender fibers, as with the general appearance of chemical fiber,But they are more than one, with extraordinary features:1. lasting thermal stability.The charac

25、teristics 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 performance can be maintained for 10 years, and excellent dimensional stability,

26、 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 strong Xiacai temperature over 370 DEG to 400 DEG C to decompose carbide, such a high thermal stability in the present is t

27、he 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 limiting oxygen index, the better the flame retardancy. Generally, the oxygen con

28、tent 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 property of the molecular structure makes Aramid 1313 permanent flame retar

29、dant, so it has the name of fire retardant fiber.3. excellent electrical insulation.Aramid 1313 low dielectric constant, dielectric strength inherent to maintain excellent electrical insulation are in high temperature, low temperature and high humidity conditions, the preparation of the paper insula

30、tion 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 connected by amide bonds,Hydrogen bonds in two planes are arranged in a three-dimensional s

31、tructure, 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. excellent mechanical characteristicsAramid 1313 flexible polymer materials, low stiffness a

32、nd 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 very extensive. Super radiation resistance.Aramid fiber 1313 is resistant to alpha,

33、 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 structure and stable with aramid fiber 1313 excellent, through the comprehensive utilizati

34、on 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 burn, does not drip, does not smoke when it is fire, and has excellent fireproof effe

35、ct. Especially in the high temperature of 900-1500 DEG C when it encountered, cloth quickly carbonization and thickening, forming unique insulation barrier that protects the wearer to escape. If a small amount of antistatic fiber or aramid fiber 1414 is added, the cloth can be effectively prevented

36、from cracking, and the hazards of lightning, arc, static electricity, flame, etc. can be avoided.With Aramid 1313 colored fibers can be made a flight suit, defense combat uniforms, fire fighting clothing and furnace work clothes, work clothes, all over welding and anti radiation clothing, chemical p

37、rotective 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 countries, such as flame retardant pajamas aramid fabric is widely used as a hotel

38、, 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 and chemical resistance, which makes it dominant in the field of high temper

39、ature 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, electric arc furnace, oil boiler, incinerator flue temperature and hot air filt

40、er, 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 Bionic multi-layer honeycomb structure plate, with outstanding strength / we

41、ight 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 wave, suitable for production aircraft, missiles and satellite broadband wave

42、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 requirements of the sandwich structure.Three, bulletproof fiber - aramid 14

43、14Almost 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®. (Kevera).A metallic liquid silk with a golden appearance and a shiny ap

44、pearance 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 unprecedented high strength, high modulus and high temperature resistance.The discov

45、ery 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 23 times of steel or glass fiber, toughness is 2 times the steel, while the weigh

46、t of only 1/5 of steel. (aramid fiber 1414s 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 -196 to 204 degrees Celsius range can long-term normal operation. Under the temperatur

47、e of 150 DEG C 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 cycle is very long, so it won synthetic wire in the world.Aramid fiber 1414 was fir

48、st 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 many other countries of the police body armor, bulletproof helmet, stab resistant clothing, EOD

49、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 energy absorption and dispersion transfer to other fabrics to avoid blunt, thus remarkable prote

50、ctive 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 1414 aramid fiber material as a kind of high science and technology has been widely used in aerospace, mech

51、anical 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 structural materials for aerospace, rocket and aircraft to reduce weight, increase payload, and save large amo

52、unts 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 fiber because of its small proportion, high strength, good heat resistance and good adhesion to rubber 1414

53、. 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 allow t