I.Polyamide resin (polyamide), abbreviated as PA, commonly known as nylon (Nylon)
II.Main naming method: according to the number of carbon atoms of each repeated amide group. The first number of the naming refers to the number of carbon atoms of the diamines, and the number after that refers to the number of carbon atoms of the dicarboxylic acid.
III.The types of nylon:
1. Nylon - 6 (PA6)
Nylon - 6, also known as polyamides - 6, that is, polycaprolactam. It is a translucent or opaque opalescent resin.
2. Nylon - 66 (PA66)
Nylon - 66, also known as polyamide - 66, that is, polyhexamethylene diamide.
3、Nylon - 1010 (PA1010)
Nylon - 1010, also known as polyamide-1010, that is, poly(sunflower diacyl sunflower diamine). Nylon - 1010 is made from castor oil as the basic raw material, is a unique species in China. Its most important feature is a high degree of ductility, can be drawn to the original length of 3 to 4 times, and high tensile strength, excellent impact and low temperature, -60 ℃ is not brittle.
4. Nylon - 610 (PA-610)
Nylon - 610, also known as polyamide-610, that is, poly(sunflower diacylhexanediamine). It is translucent milk white. Its strength is between nylon-6 and nylon-66. Small specific gravity, low crystallinity, less influence on water and humidity, good dimensional stability, and can be self-extinguishing. It is used for precision plastic parts, oil pipes, containers, ropes, conveyor belts, bearings, gaskets, insulation materials in electrical and electronics, and instrument cases.
5. Nylon - 612 (PA-612)
Nylon - 612, also known as polyamide-612, that is, polydodecanoyl hexanediamine. Nylon - 612 is a tough nylon, melting point is lower than PA66 and soft, its heat resistance and PA6 almost, but excellent hydrolysis resistance and dimensional stability, low water absorption. The main use is to do toothbrush monofilament bristles.
6. Nylon - 11 (PA-11)
Nylon - 11, also known as polyamide - 11, that is, poly-undecanolactam. It is a white translucent body. Its outstanding features are low melting temperature and processing temperature is wide, low water absorption, low temperature performance is good, can be in -40 ℃ ~ 120 ℃ to maintain the good flexibility. It is mainly used for automobile oil pipeline, brake system hose, fiber optic cable covering, packaging film, daily necessities, etc. 7.
7. Nylon - 12 (PA-12)
Nylon - 12, also known as polyamide - 12, that is, poly dodecamer. It is similar to nylon-11, but its density, melting point and water absorption rate are lower than nylon-11. It has the properties of combined polyamide and polyolefin due to its higher amount of toughening agent. Its outstanding features are high decomposition temperature, low water absorption and excellent low temperature resistance. It is mainly used in automobile oil pipes, instrument panels, gas pedals, brake hoses, anechoic parts of electronic appliances, and cable sheathing. 8.
8. Nylon - 46 (PA-46)
Nylon - 46, also known as polyamide - 46, that is, polyhexanediyl butadiamine. Its outstanding features are high crystallinity, high temperature resistance, high rigidity, high strength. It is mainly used in automobile engines and peripheral parts, such as cylinder heads, cylinder bases, oil seal covers, and transmissions.
In the electrical industry, it is used for contactors, sockets, coil bobbins, switches and other fields with high requirements for heat resistance and fatigue strength.
9. Nylon - 6T (PA-6T)
Nylon - 6T, also known as polyamide-6T, that is, poly(terephthaloylhexanediamine). Its outstanding features are high temperature resistance (melting point of 370 ℃, glass transition temperature of 180 ℃, can be used for a long time at 200 ℃), high strength, dimensional stability, good resistance to welding. Mainly used for automotive parts, oil pump cover, air filter, heat-resistant electrical parts such as wire harness terminal block, fuse, etc.
10. Nylon - 9T (PA-9T)
Nylon - 9T, also known as polyamide-6T, that is, poly-phenylene terephthalamide non-diamine. Its outstanding features are: small water absorption, water absorption rate of 0.17%; good heat resistance (melting point of 308 ℃, glass transition temperature of 126 ℃), its welding temperature up to 290 ℃. Mainly used in electronics, electrical appliances, information equipment and automotive parts.
11. Transparent nylon (semi-aromatic nylon)
Transparent nylon is an amorphous polyamide with the chemical name: poly(terephthaloyltrimethylhexanediamine). The transmission rate of visible light is 85% to 90%. Its to add in nylon components with copolymerization and steric barriers to inhibit the crystallization of nylon, so as to produce non-crystalline and difficult to crystallize structure, it maintains the original strong toughness of nylon, and get transparent thick-walled products. The mechanical properties, electrical properties, mechanical strength and rigidity of transparent nylon are almost the same level as PC and polysulfone.
12. Poly(p-phenylene terephthalamide) (aromatic nylon, abbreviated as PPA)
Polyphthalamide is a highly rigid polymer with a high degree of symmetry and regularity in its molecular structure and strong hydrogen bonds between the macromolecular chains. The polymer has high strength, high modulus, high temperature resistance, low density, low thermal shrinkage, good dimensional stability, etc., can be made into high strength, high modulus fiber (DuPont DUPONT fiber trade name: Kevlar, is the military bulletproof clothing materials).
13. monomer cast nylon (monomer cast nylon, MC nylon)
MC nylon is a kind of nylon-6, it has the following characteristics compared with general nylon.
A, better mechanical properties: MC nylon relative molecular weight than the general nylon (10000 ~ 40000) twice as high, about 35000 ~ 70000, so it is high strength, good toughness, impact resistance, fatigue resistance and better creep resistance.
B, has a certain degree of sound absorption: MC nylon has a sound-absorbing function, is a more economical and practical material to prevent mechanical noise, such as the use of it to manufacture gears.
C, with good resilience: MC nylon products bending does not produce permanent deformation, maintain strong toughness, the conditions of high impact load is a very important feature
D, with better wear resistance and self-lubricating properties.
E, with the characteristics of non-adhesive with other materials.
F, lower than the general nylon water absorption rate of 2 to 2.5 times, water absorption rate is slower, the product size stability is also better than the general nylon.
G. Simple molding and processing equipment and molds. It can be cast directly or processed by cutting, especially suitable for the production of large parts, multi-species and small-lot products that are not easily produced by injection molding machines.
14. Reactive Injection Molding Nylon (RIM nylon)
RIM nylon is a block copolymer of nylon-6 and polyether. The addition of polyether makes RIM nylon toughness, especially low-temperature toughness, excellent heat resistance, and improve the ability to bake temperature when painting.
15、IPN nylon
IPN (interpenetrating polymer mesh) nylon has similar mechanical properties as basic nylon, but has different degrees of improvement in impact strength, heat resistance, lubricity and processability. IPN nylon resin is a blended pellet made from nylon resin and a pellet containing silicone resin with vinyl functional groups or with alkyl functional groups. During processing, two different functional groups on the silicone resin cross-link to form the IPN ultra-high molecular weight silicone resin, which forms a three-dimensional mesh structure in the basic nylon resin. However, the cross-linking is only partially formed, and the finished product will continue to cross-link during storage until it is completed.
16、Electroplated nylon
Electroplated nylon is modified by filling with mineral fillers and has excellent strength, rigidity, heat resistance and dimensional stability. It has the same appearance as plated ABS, but far exceeds plated ABS in terms of performance.
The plating process of nylon is basically the same as that of ABS, i.e., the surface of the product is first browned by chemical treatment (etching process), then it is adsorbed with reduction catalyst (catalytic process), and then chemical plating and electrical plating are carried out to make copper, nickel, chromium and other metals on the surface of the product into a dense, uniform, tough and conductive film.
17、Polyimide (PI for short)
Polyimide (PI) is a polymer containing imide groups on the main chain, which has high heat and radiation resistance, non-combustibility at high temperatures, wear resistance, good dimensional stability, but poor processability.
Aliphatic polyimide (PI): poor practicality.
Aromatic polyimide (PI): with practicality (the following introduction is only for aromatic PI).
A, PI heat resistance: decomposition temperature 500 ℃ ~ 600 ℃
(some varieties can maintain each physical property for a short period of time at 555℃, and long-term use at 333℃).
B, PI resistance to very low thermal temperature: in -269 ℃ in liquid nitrogen gas will not break.
C, PI mechanical strength: unreinforced modulus of elasticity: 3 to 4 GPa; fiber reinforced: 200 GPa; above 260 ℃, the change in tensile is slower than aluminum.
D, PI irradiation resistance: stable under high temperature, vacuum, irradiation, less volatiles. High strength retention rate after irradiation.
E, PI dielectric properties.
a, dielectric constant: 3.4
b, dielectric loss: 10-3
c, dielectric strength: 100-300KV/mm
d, volume resistivity: 1017
F, PI creep resistance: at high temperatures, creep rate is smaller than aluminum.
G, friction properties: in the dry state PI VS metal to friction, can be transferred to the opposite friction surface, play a self-lubricating effect, and the coefficient of dynamic friction and static friction coefficient is very close to prevent the ability to crawl good.
H. Disadvantages: High price, which limits the application in general civil industry.
All polyamides have certain hygroscopicity, water plays the role of plasticizer in polyamide, most of the mechanical properties and electrical properties are reduced after water absorption, but the toughness and elongation at break are increased.
