One of the four high-performance fibers: aramid staple fiber
Aramid fiber is called "alicyclic polyamide fiber", which is a new type of new technology man-made fiber.
The same as ordinary cotton fibers are fluorobenzene chemical fibers, and the carbon chains of biomacromolecules have amide bonds. The rings meet.
Types of Aramid
Aramid staple fiber manufacturers believe that aramid staple aramid fiber mainly includes two types of full-alicyclic polyamide fiber and heterocyclic compound alicyclic polyamide fiber, which can be divided into ortho-aramid fiber, para-aramid fiber (PPTA) and inter-position aramid fiber. There are three kinds of para-aramid fiber (PMTA), among which the products that realize modernization mainly include two kinds of poly-aramid fiber and para-aramid fiber. Among them, the main difference between these two types of aramid fibers is that the linking position between the amide bond and the C molecule on the benzene ring is different.
✪ Pair aramid fiber
Para-aramid fiber, aramid staple fiber is polyparaphenylene terephthalamide (PPTA) chemical fiber, which is called aramid fiber 1414 in my country, and more than 85% of the amide bonds in the molecular structure chain are directly bonded to A linear polymer on the aromatic ring. It is the world's first chemical fiber made from polymer material lcd screen spinning solution, opening up a new era of high-performance man-made fibers.
✪ Meta-aramid fiber
Meta-aramid fiber, that is, polyisophthalyl-m-xylylenediamide (PMTA) chemical fiber, is also known as aramid fiber in my country. 1313 Meta-aramid fiber is a fast-growing organic chemical heat-resistant chemical fiber. The chemical fiber molecular structure is composed of fluorobenzene functional groups interconnected with meta-phenyl groups, and the molecular structure chain is linear and zigzag. Because of the strong hydrogen bonding between the molecular structures, the chemical fiber has good flame retardant grade, resistance Heat resistance, radiation resistance and other properties.
High-quality performance of aramid fiber
It has excellent properties such as extremely high compressive strength, high toughness and heat resistance, acid and alkali resistance, light weight, insulation layer, aging resistance, long life, stable chemical structure, no molten droplets when ignited, and no toxic gas. .
The high temperature resistance of para-aramid fiber is higher than that of meta-aramid fiber. The continuous application temperature range is -196°C to 204°C, and it will not dissolve or melt at a high temperature of 560°C. The most obvious characteristics of para-aramid fiber are high compressive strength, high toughness and heat resistance, acid and alkali resistance, light weight and other high-quality properties. Its hardness exceeds 25 grams per denier, which is 5 times that of high-quality stainless steel plates. ~6 times that of glass fiber, 3 times that of high-strength polyester industrial production yarn; the strain rate is 2-3 times that of high-quality stainless steel plate or glass fiber, and 10 times that of high-strength polyester industrial production yarn. The elasticity is twice that of steel wire, and the weight is only about 1/5 of that of stainless steel wire. It has excellent flame retardancy and aging resistance, and has a long life span.
✪Excellent mechanical and equipment properties of aramid fiber
Meta-aramid fiber is a kind of soft polymer material. Its elongation at break exceeds that of ordinary polyester cloth, cotton, polyester, etc. It has a large elongation, soft touch, and good spinnability. It can be processed into different deniers and lengths. High-quality polyester staple fibers and polyester yarns are made into different yarn counts on ordinary textile equipment to weave fabrics and non-woven fabrics. After post-processing, they meet the requirements of protective clothing in different industries.
✪ Excellent flame retardancy and high temperature resistance of aramid fiber
The ultimate flame retardancy (LOI) of meta-aramid fiber exceeds 28, so it is not easy to re-ignite when it leaves the flame. The flame retardant properties of Newstar® meta-aramid fiber are determined by its own chemical structure, so it is a permanent flame retardant fabric, which is not easy to reduce or lose flame retardant properties due to use time and cleaning frequency. Newstar® meta-aramid fiber has good heat resistance, can be used continuously at the standard of 205°C, and can still maintain high super strength at high temperatures exceeding 205°C. Newstar® meta-aramid fiber has a high melting temperature, and it is not easy to melt and drip under high temperature conditions, and it starts to carbonize when the ambient temperature exceeds 370°C.
✪Aramid fibers have stable physical properties
Meta-aramid fibers have good resistance to most substances, can withstand most strong oxidants with high concentrations, and have good alkali resistance at room temperature.
✪Radiation resistance of aramid fiber
The radiation resistance of meta-aramid fibers is excellent. For example, under the long-term illumination of 1.2×10-2w/in2 ultraviolet light and 1.72×108rads gamma radiation, its hardness remains unchanged.
✪ Aramid for durability
Meta-aramid fiber has excellent abrasion resistance and chemical resistance. After 100 times of washing, the tearing strength of fabrics processed with Newstar® meta-aramid fiber can still reach 85% of the original strength. above.
The main use of aramid fiber
It is widely used in many industries such as China's aerospace, vehicles, electromechanical engineering, engineering construction, sports culture, etc., and is one of the indispensable raw materials in future life.
✪Airline industry
Aramid fiber has low density, high strength, and good corrosion resistance. It can be used to produce ramjet shells for cruise missiles, as well as wide-screen wave-transmitting materials for airfields, overall fuselages of space shuttles, main wings, and tail fins. A structural member that bears impact energy. Aramid fiber prepreg is formed by pre-impregnating aramid cloth with epoxy resin glue, and directly bonded with honeycomb or foam structure to make a double-layer honeycomb structure board, which has strong wear resistance and wireless Wave passability and other properties. The super-hybrid composite multi-layer board established by laminating aramid fiber with thin aluminum alloy board and epoxy resin non-weft cloth has a high specific strain rate and specific strength, and the service life of fatigue relief is 100 times that of aluminum board. Times to 1000 times, can be used in the overall fuselage of the airport and other positions. The epoxy resin-based enhanced composite material made of aramid fiber is used in the main body of the airport, which can greatly reduce the total weight of the airport.
✪Defense industry
Along with the development trend of new military weapons and equipment such as organic chemistry and nuclear, there are more new regulations on the performance of military protective clothing: durable, lightweight, EXO, flame retardancy and better natural environment adaptability and concealment etc. The body armor and bulletproof helmet made of aramid can replace the old polyester camisole and tank helmet. Adding a proper amount of aramid fiber to the body armor and hat can not only make it small in size and light in weight, but also increase the EXO efficiency by 40 %. The soft plastic body armor made of high-end EXO aramid fiber non-weft fabric and high-performance polyethylene film has stronger EXO performance and temperature resistance than polyethylene fiber with very high relative molecular weight. Aramid can also be compounded with other materials (such as metals, ceramics, etc.) to make a variety of high-strength, impact-resistant explosion-proof tanks, bulletproof shields and EXO armor plates, etc. In addition, the aramid fabric is bonded to the inner cavity of the structure, which can efficiently absorb the blast wave and avoid the damage of the spring to the body.
✪Engineering and construction industry
The plasticity of aramid fabric is better than that of carbon fiber materials. Aramid staple fiber raw materials are light in weight and flexible in playability. Because of its good flexibility, do not round the corners when the structure is reinforced. Weaving aramid fibers into steel bars can be used as reinforced concrete frames for large-scale buildings. In addition to the advantages of high strength and light weight, it is also corrosion-resistant, and at the same time has a good anti-cutting effect.
✪Transportation industry
Because aramid fiber has low density, high and low temperature resistance, and good adhesion to rubber, it can be used as tire cord for vehicles or airports. The tire made of aramid fiber is light in weight, thin in tire, low in turning frictional resistance, high in tire bearing capacity, good wear resistance, laser cutting resistance and puncture resistance, and the tire is grounded during the whole process of application Small movement of center of gravity under pressure, good steering performance, easy to dissipate heat, not easy to deform, improve the ride comfort of the car, extend the service life of the tire, and meet the application requirements of modern jet aircraft for car tires .
✪Electronic appliances industry
Aramid fiber has high hardness and strain rate and low electric polarization index, and the radio wave transmittance is good. Under the same bending stiffness, the radar detection wireless antenna protective cover made of aramid fiber composite material is thinner than glass fiber composite material. The material can be reduced by 30%, and the radio wave transmittance can be increased by 10%; the thermal expansion coefficient of the laminated steel plate made of aramid fiber and epoxy resin, phenolic resin, polyacrylonitrile and other epoxy resins is more compatible with that of porcelain High, it is impossible to cause cracks under the effect of thermal expansion and contraction, and can be used to make special printed circuit boards in surface assembly technology, which is beneficial to the practicality and light weight of electronic products.
Using aramid fiber's high compressive strength and heat resistance, it is used as a "supportive prefabricated component" in the optical fiber, which can protect the delicate and sensitive optical fiber from stretching and deformation when it is subjected to tensile force, and is not easy to affect the light. send. The composite product of aramid fiber and carbon fiber has excellent processability, semiconductor properties, and heat resistance, and is mostly used to make materials for reducing electrostatic fields in high-voltage equipment. After the aramid paper is pre-impregnated with three-proof paint, it has good insulation performance, and it is combined with natural mica as the insulation layer material of the temperature-resistant motor.
✪Other industries
The molecular structure of aramid fiber contains a lot of benzene rings, it has good chemical stability, corrosion resistance, high specific strength, light and long, and can be used to produce nylon ropes for seagoing vessels and deepwater wells. Use aramid fiber heat resistance, fatigue resistance and other properties to make high-level table tennis rackets, fishing rods, sleds, snowboards, skating poles, crossbows, kayaks, golf equipment, etc., and can also be used to make fitness Mountaineering shoes, boxing gloves, racing helmets, sports car bodies, etc. with strict sports standards. Because asbestos poses a serious threat to the human respiratory system, aramid fiber can be used instead of asbestos to make hydraulic seals such as improved sealing gasket plates, which are used for gaskets and linings of automobile braking systems.
