Herstellung von Kevlar-Fasern (Poly-p-phenyleneterephthalamid)

Die Aramidfaser, die gewichtsbezogen fünfmal stärker als Stahl ist

Materials Science & Polymers Commercial Production $3.5 billion

Übersicht

Kevlar is a para-aramid fiber produced by the polycondensation of p-phenylenediamine and terephthaloyl chloride in solution, followed by dry-jet wet spinning. Invented by Stephanie Kwolek at DuPont in 1965, Kevlar has a tensile strength-to-weight ratio five times that of steel. Its liquid crystalline behavior in solution enables production of highly oriented fibers with exceptional mechanical properties. Applications include body armor, cut-resistant gloves, tire reinforcement, aerospace composites, and fiber-optic cables.

Chemischer Prozess

p-Phenylenediamine is dissolved in N-methyl-2-pyrrolidone (NMP) with CaCl2 at -10 degrees C. Terephthaloyl chloride in NMP is added rapidly with vigorous stirring, producing the polymer as a gel. The polymer is dissolved in concentrated sulfuric acid (19.4% w/w) to form a liquid crystalline dope, which is extruded through a spinneret into an air gap and then a water coagulation bath (dry-jet wet spinning).

nH2N-C6H4-NH2 + nClOC-C6H4-COCl -> -[NH-C6H4-NH-CO-C6H4-CO]n- + 2nHCl (low-temperature polycondensation)

Rohstoffe

  • p-Phenylenediamine (C6H4(NH2)2) — Reduction of p-nitroaniline (Diamine monomer)
  • Terephthaloyl chloride (ClOC-C6H4-COCl) — Chlorination of terephthalic acid (Diacid chloride monomer)
  • Concentrated sulfuric acid (H2SO4) — Contact process (Spinning solvent for liquid crystalline dope)

Endprodukte

  • Kevlar fiber (poly-p-phenylene terephthalamide) — Body armor, tire cord, cut-resistant gloves, composites (Tensile strength 3.6 GPa, modulus 130 GPa)
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Environmental Impact

The use of concentrated sulfuric acid as spinning solvent and NMP in polymerization generates hazardous waste requiring careful recovery. HCl byproduct is captured and neutralized. Kevlar fibers are extremely durable and persist indefinitely in the environment, but the small production volume limits overall impact.

Sicherheitshinweise

Neuere Innovationen

DuPont has developed solvent-free Kevlar processing for certain applications.
Recycled Kevlar pulp from end-of-life body armor is used in brake pads and gaskets.
New copolymer aramids offer improved dyeability and UV resistance.

Produktionsmaßstab

70000

Tonnen/Jahr

$3.5 billion

Marktwert

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Frequently Asked Questions

What industry uses Herstellung von Kevlar-Fasern (Poly-p-phenyleneterephthalamid)?
Herstellung von Kevlar-Fasern (Poly-p-phenyleneterephthalamid) is used in the materials science & polymers sector at commercial production scale.
What process is involved in Herstellung von Kevlar-Fasern (Poly-p-phenyleneterephthalamid)?
p-Phenylenediamine is dissolved in N-methyl-2-pyrrolidone (NMP) with CaCl2 at -10 degrees C. Terephthaloyl chloride in NMP is added rapidly with vigorous stirring, producing the polymer as a gel. The polymer is dissolved in concentrated sulfuric acid (19.4% w/w) to form a liquid crystalline dope, wh
What is the economic significance of Herstellung von Kevlar-Fasern (Poly-p-phenyleneterephthalamid)?
Herstellung von Kevlar-Fasern (Poly-p-phenyleneterephthalamid) has a market value of $3.5 billion and annual production of 70,000 tons.
What is the environmental impact of Herstellung von Kevlar-Fasern (Poly-p-phenyleneterephthalamid)?
The use of concentrated sulfuric acid as spinning solvent and NMP in polymerization generates hazardous waste requiring careful recovery. HCl byproduct is captured and neutralized. Kevlar fibers are extremely durable and persist indefinitely in the environment, but the small production volume limits
What raw materials are used in Herstellung von Kevlar-Fasern (Poly-p-phenyleneterephthalamid)?
The main raw materials include: p-Phenylenediamine (C6H4(NH2)2), Terephthaloyl chloride (ClOC-C6H4-COCl), Concentrated sulfuric acid (H2SO4).