Nylon material is widely used, small to nylon stockings, large to car engine peripheral parts, etc., has covered all aspects of our lives. Different application areas, the requirements for nylon material properties are also different, such as high temperature resistance, wear resistance and impact resistance, chemical agent resistance, transparency and resilience.
Conventional nylon, generally refers to PA6, PA66 two common varieties. Conventional nylon in enhanced, flame retardant and other modifications will still have large shortcomings, such as strong hydrophilicity, high temperature resistance, poor transparency and so on, limiting more applications.
Therefore, in order to improve the shortcomings and increase new characteristics, generally by introducing new synthetic monomers, we can get a series of special nylon with different characteristics that can meet different use occasions, mainly divided into high temperature nylon, long carbon chain nylon, transparent nylon, bio-based materials nylon and nylon elastomer and so on.
Then, let's talk about the categories of special nylon, their characteristics and applications.
Classification and application examples of special nylon
1. High temperature resistance -- high temperature nylon
First of all, high-temperature nylon refers to nylon materials that can be used in an environment above 150 ° C 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's Kevlar, which is prepared by the reaction of p-benzoyl chloride with p-phenylenediamine or p-amino-benzoic acid, referred to as PPTA, can maintain good strength at 280 ° C for 200h.
However, the whole aromatic high temperature nylon is not good to process and difficult to achieve injection molding, so the semi-aromatic high temperature nylon combined with aliphatic and aromatic is more favored. At present, most high-temperature nylon varieties, such as PA4T, PA6T, PA9T, PA10T, etc., are basically semi-aromatic high-temperature nylon polymerized from straight chain aliphatic diamine and terephthalic acid.
High temperature nylon is widely used in automotive parts, mechanical parts and electrical/electronic parts.
2. High toughness - long carbon chain nylon
The second is long carbon chain nylon, which generally refers to nylon materials with more than 10 methylenes in the molecular chain.
On the one hand, long carbon chain nylon has more methylene groups, so it has high toughness and softness. On the other hand, the reduction of the density of amide groups on the molecular chain greatly reduces the hydrophilicity and improves its dimensional stability, and its varieties are PA11, PA12, PA610, PA1010, PA1212 and so on.
As an important variety of engineering plastics, long carbon chain nylon has the advantages of low water absorption, good low temperature resistance, stable size, good toughness, wear-resistant shock absorption, etc., and is widely used in automotive, communications, machinery, electronic appliances, aerospace, sporting goods and other fields.
3. High transparency - transparent nylon
Conventional nylon is usually translucent appearance, light transmittance between 50% and 80%, and transparent nylon light transmittance is generally more than 90%.
Transparent nylon can be modified by physical and chemical methods. The physical method is to add nucleating agent and reduce its grain size to the visible wavelength range to obtain microcrystalline transparent nylon. The chemical method is to introduce monomer containing side group or ring structure, destroy the regularity of molecular chain, and obtain amorphous transparent nylon.
Transparent nylon can be used for beverage and food packaging, but also can manufacture optical instruments and computer parts, industrial production of monitoring Windows, X-ray instrument window, metering instruments, electrostatic copier developer storage, special lamps cover, utensils and food contact containers.
4. Sustainability – Bio-based Materials Nylon
At present, most of the synthetic monomers of nylon varieties are from the petroleum refining route, and the synthetic monomer of bio-based materials nylon is from the biological raw material extraction route, such as Arkema through the castor oil extraction route to obtain amino undecanoic acid and then synthetic nylon 11.
Compared with the traditional oil-based materials nylon, the bio-based materials nylon not only has significant low-carbon and environmental advantages, but also can meet the different performance needs of the solution, such as Shandong Kaisai bio-based PA5X series, Arkema Rilsan series in the automotive parts, electronic appliances and 3D printing industry and other aspects have been successfully applied.
5. High elasticity -- nylon elastomer
Nylon elastomer refers to nylon varieties with high resilience, light weight and other characteristics, but it is worth mentioning that the molecular chain composition of nylon elastomer is not all polyamide chain segments, and polyether or polyester chain segments, the most common commercial variety is polyether block amide (PEBA).
The performance characteristics of PEBA are high tensile strength, good elastic recovery, high low temperature impact strength, excellent low temperature resistance, excellent antistatic performance, etc., which is used in mountaineering shoes, ski boots, silencing gear and medical catheters.
Post time: Dec-27-2023