Nylon 6

Last updated
Nylon 6
Polycaprolactam.svg
Names
IUPAC name
Poly(azepan-2-one); poly(hexano-6-lactam)
Systematic IUPAC name
Poly[azanediyl(1-oxohexane-1,6-diyl)]
Other names
Polycaprolactam, polyamide 6, PA6, poly-ε-caproamide, Perlon, Dederon, Capron, Ultramid, Akulon, Nylatron, Kapron, Alphalon, Tarnamid, Akromid, Frianyl, Schulamid, Durethan, Technyl, Nyorbits ,Winmark Polymers
Identifiers
ChemSpider
  • None
ECHA InfoCard 100.124.824 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
Properties
(C6H11NO)n
Density 1.084 g/mL [ citation needed ]
Melting point 218.3 °C (493 K)
Hazards
434 °C; 813 °F; 707 K
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Caprolactam molecule used to synthesize Nylon 6 by ring opening polymerization Caprolactam-2D-skeletal.png
Caprolactam molecule used to synthesize Nylon 6 by ring opening polymerization

Nylon 6 or polycaprolactam is a polymer, in particular semicrystalline polyamide. Unlike most other nylons, nylon 6 is not a condensation polymer, but instead is formed by ring-opening polymerization; this makes it a special case in the comparison between condensation and addition polymers. Its competition with nylon 6,6 and the example it set have also shaped the economics of the synthetic fibre industry. It is sold under numerous trade names including Perlon (Germany), Dederon (former East Germany), [1] Nylatron, Capron, Ultramid, Akulon, Kapron (former Soviet Union and satellite states), Rugopa (Turkey) and Durethan.

Contents

History

Polycaprolactam was developed by Paul Schlack at IG Farben in late 1930s (first synthesized in 1938) to reproduce the properties of Nylon 66 without violating the patent on its production. (Around the same time, Kohei Hoshino at Toray also succeeded in synthesizing nylon 6.) It was marketed as Perlon, and industrial production with a capacity of 3,500 tons per year was established in Nazi Germany in 1943, using phenol as a feedstock. At first, the polymer was used to produce coarse fiber for artificial bristle, then the fiber quality was improved, and Germans started making parachutes, cord for aircraft tires and towing cables for gliders.

The Soviet Union began its development of an analog in the 1940s, while negotiating with Germany on building an IG Farben plant in Ukraine,[ when? ] basic scientific work was ongoing in 1942. The production only started in 1948 in Klin, Moscow Oblast, after USSR obtained the 2000 volumes of IG Farben, and 10,000 volumes of AEG technical documentation, [2] as a result of victory in the World War II.

Synthesis

Nylon 6 can be modified using comonomers or stabilizers during polymerization to introduce new chain end or functional groups, which changes the reactivity and chemical properties. It is often done to change its dyeability or flame retardance. [3] Nylon 6 is synthesized by ring-opening polymerization of caprolactam. Caprolactam has 6 carbons, hence Nylon 6. When caprolactam is heated at about 533  K in an inert atmosphere of nitrogen for about 4–5 hours, the ring breaks and undergoes polymerization. Then the molten mass is passed through spinnerets to form fibres of nylon 6.

Polymerization of caprolactam to Nylon 6. Caprolactam polymerization.png
Polymerization of caprolactam to Nylon 6.

During polymerization, the amide bond within each caprolactam molecule is broken, with the active groups on each side re-forming two new bonds as the monomer becomes part of the polymer backbone. Unlike nylon 6,6, in which the direction of the amide bond reverses at each bond, all nylon 6 amide bonds lie in the same direction (see figure: note the N to C orientation of each amide bond).

Nylon 6 (above) has a structure similar to Nylon 6,6 (below). Nylon 6 and Nylon 6-6.svg
Nylon 6 (above) has a structure similar to Nylon 6,6 (below).

Properties

Nylon 6 fibres are tough, possessing high tensile strength, elasticity and lustre. They are wrinkleproof and highly resistant to abrasion and chemicals such as acids and alkalis. The fibres can absorb up to 2.4% of water, although this lowers tensile strength. The glass transition temperature of Nylon 6 is 47 °C.

As a synthetic fibre, Nylon 6 is generally white but can be dyed in a solution bath prior to production for different color results. Its tenacity is 6–8.5  gf/D with a density of 1.14 g/cm3. Its melting point is at 215 °C and can protect heat up to 150 °C on average. [4]

Biodegradation

Flavobacterium sp. [85] and Pseudomonas sp. (NK87) degrade oligomers of Nylon 6, but not polymers. Certain white rot fungal strains can also degrade Nylon 6 through oxidation. Compared to aliphatic polyesters, Nylon 6 has been said to have poor biodegradability. Strong interchain interactions from hydrogen bonds between molecular nylon chains is said to be the cause by some sources. [5]

However, in 2023 a team of Northwestern University chemists led by Linda Broadbelt and Tobin J. Marks developed rare earth metallocene catalysts that rapidly break Nylon 6 down back to caprolactam at 220°C, which is considered mild conditions. [6] [7] [8]

Production in Europe

At present, polyamide 6 is a significant construction material used in many industries, for instance in the automotive industry, aircraft industry, electronic and electrotechnical industry, clothing industry and medicine. Annual demand for polyamides in Europe amounts to a million tonnes. They are produced by all leading chemical companies.

The largest producers of polyamide 6 in Europe: [9]

  1. Fibrant, 260,000 tonnes per year
  2. BASF, 240,000 tonnes per year
  3. Lanxess, 170,000 tonnes per year
  4. Radici, 125,000 tonnes per year
  5. DOMO, 100,000 tonnes per year
  6. Grupa Azoty, 100,000 tonnes per year [10] [11]

Related Research Articles

<span class="mw-page-title-main">Condensation polymer</span> Polymer produced via a condensation reaction

In polymer chemistry, condensation polymers are any kind of polymers whose process of polymerization involves a condensation reaction. Natural proteins as well as some common plastics such as nylon and PETE are formed in this way. Condensation polymers are formed by polycondensation, when the polymer is formed by condensation reactions between species of all degrees of polymerization, or by condensative chain polymerization, when the polymer is formed by sequential addition of monomers to an active site in a chain reaction. The main alternative forms of polymerization are chain polymerization and polyaddition, both of which give addition polymers.

<span class="mw-page-title-main">Nylon</span> Early synthetic polymer developed as a textile fibre

Nylon is a family of synthetic polymers with amide backbones, usually linking aliphatic or semi-aromatic groups.

<span class="mw-page-title-main">Petrochemical</span> Chemical product derived from petroleum

Petrochemicals are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.

<span class="mw-page-title-main">BASF</span> German chemicals company

BASF SE, an initialism of its original name Badische Anilin- und Sodafabrik, is a German multinational company and the largest chemical producer in the world. Its headquarters are located in Ludwigshafen, Germany.

<span class="mw-page-title-main">Aramid</span> Class of synthetic fiber

Aramid fibers, short for aromatic polyamide, are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in marine cordage, marine hull reinforcement, as an asbestos substitute, and in various lightweight consumer items ranging from phone cases to tennis rackets.

A polyamide is a polymer with repeating units linked by amide bonds.

<span class="mw-page-title-main">Caprolactam</span> Chemical compound

Caprolactam (CPL) is an organic compound with the formula (CH2)5C(O)NH. This colourless solid is a lactam (a cyclic amide) of caproic acid. Global demand for this compound is approximately five million tons per year, and the vast majority is used to make Nylon 6 filament, fiber, and plastics.

<span class="mw-page-title-main">Cyclohexanone</span> Chemical compound

Cyclohexanone is the organic compound with the formula (CH2)5CO. The molecule consists of six-carbon cyclic molecule with a ketone functional group. This colorless oily liquid has a sweet odor reminiscent of benzaldehyde. Over time, samples of cyclohexanone assume a pale yellow color. Cyclohexanone is slightly soluble in water and miscible with common organic solvents. Millions of tonnes are produced annually, mainly as a precursor to nylon.

<span class="mw-page-title-main">Polybutadiene</span> Type of synthetic rubber formed from the polymerization of butadiene

Polybutadiene [butadiene rubber, BR] is a synthetic rubber. It offers high elasticity, high resistance to wear, good strength even without fillers, and excellent abrasion resistance when filled and vulcanized. "Polybutadiene" is a collective name for homopolymers formed from the polymerization of the monomer 1,3-butadiene. The IUPAC refers to polybutadiene as "poly(buta-1,3-diene)". Historically, an early generation of synthetic polybutadiene rubber produced in Germany by Bayer using sodium as a catalyst was known as "Buna rubber". Polybutadiene is typically crosslinked with sulphur, however, it has also been shown that it can be UV cured when bis-benzophenone additives are incorporated into the formulation.

<span class="mw-page-title-main">Polyphthalamide</span>

Polyphthalamide is a subset of thermoplastic synthetic resins in the polyamide (nylon) family defined as when 55% or more moles of the carboxylic acid portion of the repeating unit in the polymer chain is composed of a combination of terephthalic (TPA) and isophthalic (IPA) acids. The substitution of aliphatic diacids by aromatic diacids in the polymer backbone increases the melting point, glass transition temperature, chemical resistance and stiffness.

<span class="mw-page-title-main">Polyester</span> Category of polymers, in which the monomers are joined together by ester links

Polyester is a category of polymers that contain one or two ester linkages in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in plants and insects, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing.

Paul Schlack was a German chemist. He completed his studies at the Technical University of Stuttgart in 1921 and worked as a research chemist in Copenhagen for a year, before returning to Stuttgart. He received his PhD in 1924. Around this time he developed a keen interest in amide chemistry. He synthesized Nylon 6, widely known by its tradename Perlon, on 29 January 1938 whilst working for IG Farben.

Nylon 66 is a type of polyamide or nylon. It, and nylon 6, are the two most common for textile and plastic industries. Nylon 66 is made of two monomers each containing 6 carbon atoms, hexamethylenediamine and adipic acid, which give nylon 66 its name. Aside from its superior physical characteristics, nylon 66 is attractive because its precursors are inexpensive.

<span class="mw-page-title-main">Laurolactam</span> Chemical compound

Laurolactam is an organic compound from the group of macrocyclic lactams. Laurolactam is mainly used as a monomer in engineering plastics, such as nylon-12 and copolyamides.

<span class="mw-page-title-main">Radici Group</span>

RadiciGroup is an Italian corporation with a network of production and sales sites located in Europe, North America, South America and Asia. RadiciGroup is one of the world’s leading producers of a wide range of chemical intermediates, polyamide polymers, engineering plastics, synthetic fibres and nonwovens.

<span class="mw-page-title-main">Aluminium diethyl phosphinate</span> Chemical compound

Aluminium diethyl phosphinate is a chemical compound with formula Al(C
4
H
10
O
2
P
)3. It decomposes above 300 °C.

<span class="mw-page-title-main">Nylon 46</span> Chemical compound

Nylon 46 is a high heat resistant polyamide or nylon. Envalior is the only commercial supplier of this resin, which markets under the trade name Stanyl. Nylon 46 is an aliphatic polyamide formed by the polycondensation of two monomers, one containing 4 carbon atoms, 1,4-diaminobutane (putrescine), and the other 6 carbon atoms, adipic acid, which give nylon 46 its name. It has a higher melting point than nylon 6 or nylon 66 and mainly used in applications which must withstand high temperatures.

<span class="mw-page-title-main">Grupa Azoty</span> Polish chemical company

Grupa Azoty S.A. is a major Polish chemical industry company headquartered in the Mościce district of Tarnów, in the Lesser Poland Voivodeship of southeastern Poland.

Grupa Azoty ATT Polymers GmbH – one of the enterprises producing polyamide 6 (PA6) in Western Europe. Acquired by Zakłady Azotowe w Tarnowie-Mościcach in 2009, currently a member of Grupa Azoty, in production of fertilizers, construction materials and caprolactam. Grupa Azoty ATT POLYMERS is seated in Guben, (Germany).

<span class="mw-page-title-main">Marl Chemical Park</span> Industrial park in Marl, North Rhine-Westphalia, Germany

Marl Chemical Park is an industrial park in Marl, North Rhine-Westphalia, Germany. It is the third largest industrial cluster in Germany and among the largest chemical production facilities in Europe. The site occupies over 6 square kilometers, hosts 100 chemical plants, employs 10,000 people, and produces 4 million metric tons of chemicals annually. 18 companies are based in the Park, including primary tenant Evonik Industries AG, which also owns and operates the infrastructure through its subsidiary Infracor GmbH.

References

  1. Rubin, E. (2014), Synthetic Socialism: Plastics and Dictatorship in the German Democratic Republic. The University of North Carolina Press. ISBN   978-1469615103
  2. Zaharov, V.V. (2007). Советская военная администрация в Германии 1945-1949: Деятельность Управления СВАГ по изучению достижений немецкой науки и техники в Советской зоне оккупации Германии[Soviet military administration in Germany 1945-1949: Activities of the SMAG Directorate for studying the achievements of German science and technology in the Soviet zone of occupation of Germany] (in Russian). Moscow: ROSSPEN, Russian State Archive. p. 65. ISBN   978-5-8243-0882-2.
  3. "Synthesis of Modified Polyamides (Nylon 6)", NPTEL (National Programme On Technology Enhanced Learning), retrieved May 9, 2016
  4. Polyamide Fiber Physical and Chemical Properties of Nylon 6”, textilefashionstudy.com, retrieved May 9, 2016.
  5. Tokiwa, Y.; Calabia, B. P.; Ugwu, C. U.; Aiba, S. (2009). "Biodegradability of Plastics". International Journal of Molecular Sciences. 10 (9): 3722–42. doi: 10.3390/ijms10093722 . PMC   2769161 . PMID   19865515.
  6. "New Catalyst Completely Breaks Down Durable Plastic Pollution in Minutes". 3 December 2023.
  7. Ye, Liwei; Liu, Xiaoyang; Beckett, Kristen; Rothbaum, Jacob O.; Lincoln, Clarissa; Broadbelt, Linda J.; Kratish, Yosi; Marks, Tobin J. (2023-04-27), Catalyst Design to Address Nylon Plastics Recycling, doi:10.26434/chemrxiv-2023-h91np , retrieved 2024-10-09
  8. Ye, Liwei; Liu, Xiaoyang; Beckett, Kristen B.; Rothbaum, Jacob O.; Lincoln, Clarissa; Broadbelt, Linda J.; Kratish, Yosi; Marks, Tobin J. (January 2024). "Catalyst metal-ligand design for rapid, selective, and solventless depolymerization of Nylon-6 plastics". Chem. 10 (1): 172–189. Bibcode:2024Chem...10..172Y. doi:10.1016/j.chempr.2023.10.022. ISSN   2451-9294.
  9. "Segment Tworzywa 2015" (PDF) (in Polish). static.grupaazoty.com. Retrieved 2016-04-12.
  10. "Alphalon™ (PA6)" (in Polish). att.grupaazoty.com. Archived from the original on 2016-04-26. Retrieved 2016-04-12.
  11. "Grupa Azoty: Nowa wytwórnia pozwoli zająć pozycję 2. producenta poliamidu w UE" (in Polish). wyborcza.biz. Retrieved 2016-04-12.