What do you know about five types of special nylon?
TIME：2021-10-7
Different from conventional nylon (PA6, PA66), by introducing new synthetic monomers, a series of special nylon with different characteristics and can meet different applications can be obtained, mainly including high-temperature nylon, long carbon chain nylon, transparent nylon, bio based nylon and nylon elastomer.
01 high temperature resistant - high temperature nylon
High temperature nylon refers to nylon materials that can be used above 150 ℃ for a long time.
The high temperature resistance of high temperature nylon is generally obtained by introducing rigid aromatic monomers. For example, all aromatic nylon, the most typical is DuPont Kevlar, which is prepared by the reaction of p-benzoyl chloride with p-phenylenediamine or p-aminobenzoic acid, abbreviated as PPTA. It can maintain good strength after 200H at a high temperature of 280 ℃.
However, the processing of all aromatic high-temperature nylon is difficult and it is difficult to realize injection molding, so the semi aromatic high-temperature nylon combined with aliphatic and aromatic is more popular. At present, most high-temperature nylon varieties, such as pa4t, PA6T, PA9T, pa10t, etc., are basically semi aromatic high-temperature nylon polymerized by linear aliphatic diamine and terephthalic acid.
High temperature nylon is widely used in automobile parts, mechanical parts and electrical / electronic parts.
02 high toughness - long carbon chain nylon
Long carbon chain nylon generally refers to nylon materials with more than 10 methylene groups in the molecular chain.
On the one hand, long carbon chain nylon has high toughness and flexibility because it has more methylene groups. On the other hand, the reduced density of amide groups on the molecular chain greatly reduces the water absorption and improves its dimensional stability. Its varieties include PA11, PA12, PA610, PA1010, pa1212, etc.
As an important variety of engineering plastics, long carbon chain nylon has the advantages of low water absorption, good low temperature resistance, dimensional stability, good toughness, wear resistance and shock absorption. It is widely used in the fields of automobile, communication, machinery, electronics, aerospace, sporting goods and so on.
03 high transparency - Transparent Nylon
Conventional nylon is usually translucent, with a light transmittance of 50% - 80%, while the light transmittance of transparent nylon is generally more than 90%.
Transparent nylon can be modified by physical and chemical methods. The physical method is to add nucleating agent to reduce the grain size to the visible wavelength range to obtain microcrystalline transparent nylon. Chemical method is to introduce monomer with side group or ring structure to destroy the regularity of molecular chain and obtain amorphous transparent nylon.
Transparent nylon can be used for beverage and food packaging. It can also be used to manufacture optical instruments and computer parts, monitoring windows for industrial production, peeping windows of X-ray instruments, measuring instruments, electrostatic copiers, developer storage tanks, special lamp covers, tableware and containers in contact with food, etc.
04 sustainability - biokinilon
At present, the synthetic monomers of most nylon varieties come from the petroleum refining route, while the synthetic monomers of bio based nylon come from the biological raw material extraction route. For example, akoma obtains aminoundecanoic acid through the castor oil extraction route to synthesize nylon 11.
Compared with traditional petroleum based nylon, bio based nylon not only has significant low-carbon and environmental protection advantages, but also can meet different performance requirements. For example, Shandong Kaisai bio based pa5x series and akoma rilsan series have been successfully applied in automobile parts, electronics and 3D printing industry.
05 high elasticity - Nylon elastomer
Nylon elastomer refers to nylon varieties with high resilience and light weight, but it is worth mentioning that the molecular chain composition of nylon elastomer is not all polyamide segments, but also polyether or polyester segments. The most common commercial variety is polyether block amide (PEBA).
The performance characteristics of PEBA mainly include high tensile strength, good elastic recovery, high low-temperature impact strength, excellent low-temperature resistance, excellent antistatic performance, etc. PEBA is applied to mountaineering shoes, ski boots, silencing gears and medical catheters.
