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What is nylon? What is pa?

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What kinds can you list

PA: polyamide, commonly known as nylon
properties: nylon is a tough angular translucent or milky crystalline resin. The molecular weight of nylon as an engineering plastic is generally 15000-30000. Nylon has high mechanical strength, high softening point, heat resistance, low friction coefficient, wear resistance, self lubrication, shock absorption and silencing, oil resistance, weak acid resistance, alkali resistance and general solvents, good electrical insulation, self extinguishing, non-toxic, odorless, good weather resistance and poor dyeing. The disadvantage is that the water absorption is large, which affects the dimensional stability and electrical properties. Fiber reinforcement can reduce the water absorption of the resin, so that it can work under high temperature and high humidity. Nylon has good affinity with glass fiber. It is often used to make comb, toothbrush, clothes hook, fan bone, net bag rope, fruit outer packing bag and so on. Non toxic, but not long-term contact with acid and alkali
it should be noted that after adding glass fiber, the tensile strength of nylon can be increased by about 2 times, and the temperature resistance can be improved accordingly
the shrinkage of nylon is 1% ~ 2%
nylon types: the main varieties of nylon are nylon 6 and nylon 66, which are absolutely dominant, followed by nylon 11, nylon 12, nylon 610 and nylon 612. In addition, there are nylon 1010, nylon 46, nylon 7, nylon 9 and nylon 13. New varieties include nylon 6I, nylon 9t and special nylon MXD6 (barrier resin). There are a large number of modified varieties of nylon, such as reinforced nylon, Monomer casting nylon (MC nylon), reaction injection molding (RIM) nylon, aromatic nylon, transparent nylon, high impact (super tough) nylon, electroplated nylon, conductive nylon, flame retardant nylon, blends and alloys of nylon and other polymers meet different special requirements. They are widely used as substitutes for traditional materials such as metal and wood and as various structural materials
modification of nylon
due to the strong polarity of PA, it has strong moisture absorption and poor dimensional stability, but it can be improved by modification
?? Glass fiber reinforced PA
when 30% glass fiber is added to PA, the mechanical properties, dimensional stability, heat resistance and aging resistance of PA are significantly improved, and the fatigue strength is 2.5 times that of unreinforced PA. The molding process of glass fiber reinforced PA is roughly the same as that without reinforcement, but because the flow is worse than that before reinforcement, the injection pressure and injection speed should be appropriately increased, and the barrel temperature should be increased by 10-40 ℃. Because the glass fiber will be oriented along the flow direction in the injection molding process, resulting in the enhancement of mechanical properties and shrinkage in the orientation direction, resulting in the deformation and warpage of the product. Therefore, in the mold design, the position and shape of the gate should be reasonable, and the temperature of the mold can be improved in the process. After the product is taken out, put it into hot water to cool it slowly. In addition, the greater the proportion of glass fiber added, the greater the wear of the plasticizing elements of the injection molding machine. It is best to use bimetallic screw and barrel
?? Flame retardant PA
due to the addition of flame retardant in PA, most flame retardants are easy to decompose at high temperature, release acidic substances and have corrosive effect on metals. Therefore, plasticized elements (screw, rubber head, rubber ring, rubber washer, flange, etc.) need to be plated with hard chromium. In terms of process, try to control the barrel temperature not too high and the injection speed not too fast, so as to avoid the discoloration and degradation of mechanical properties of products caused by the decomposition of rubber due to too high temperature
?? Transparent PA
has good tensile strength, impact strength, rigidity, wear resistance, chemical resistance, surface hardness and other properties. It has high light transmittance and is similar to optical glass. The processing temperature is 300-315 ℃. During molding, the barrel temperature needs to be strictly controlled. If the melt temperature is too high, the product will change color due to degradation, If the temperature is too low, the transparency of the product will be affected due to poor plasticization. The mold temperature shall be lower as far as possible. High mold temperature will reduce the transparency of products due to crystallization
?? Weather resistant PA
carbon black and other UV absorbing additives are added to PA, which greatly enhance the self lubrication of PA and the wear of metal, and will affect the blanking and wear parts during molding processing. Therefore, it is necessary to adopt the combination of screw, barrel, rubber head, rubber ring and rubber washer with strong feeding capacity and high wear resistance

PA is nylon
PA nylon is mainly used for synthetic fibers. Its most prominent advantage is that its wear resistance is higher than all other fibers. It is 10 times higher than that of cotton and 20 times higher than that of wool. Adding a little PA nylon fiber to the blended fabric can greatly improve its wear resistance; When stretched to 3-6%, the elastic recovery rate can reach 100%; It can withstand tens of thousands of bending without breaking. The strength of PA nylon fiber is 1-2 times higher than that of cotton, 4-5 times higher than that of wool and 3 times higher than that of viscose fiber. However, the heat resistance and light resistance of PA nylon fiber are poor, and the retention is also poor. The clothes made of PA nylon fiber are not as neat as polyester. In addition, nylon-66 and nylon-6 used for clothing have the disadvantages of poor moisture absorption and dyeing. Therefore, a new variety of PA nylon fiber, new polyamide fiber of nylon-3 and nylon-4, has been developed. It has the characteristics of light weight, excellent wrinkle resistance, good air permeability, good durability, dyeing and heat setting, so it is considered to be very promising

PA nylon, with a density of 1.15g/cm3, is the general name of thermoplastic resins containing repeated amide group – [nhco] – in the molecular main chain, including aliphatic PA, aliphatic aromatic PA and aromatic PA. Aliphatic PA has many varieties, large output and wide application. Its name is determined by the specific number of carbon atoms of the synthetic monomer. It was invented by the famous American chemist Carol Sears and his research team.

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