Cuprammonium rayon is a rayon fiber made from cellulose dissolved in a cuprammonium solution,[1] Schweizer's reagent.[2]

Brown cupra (also known as cupro or Bemberg) fabric made of rayon
Lab demonstration of the process. When a solution of cellulose in cuprammonium hydroxide comes into contact with sulfuric acid, the cellulose begins to precipitate from the solution. The sulfuric acid reacts with a complex compound of copper and dissolves it. Thin blue fibers of rayon are formed. After some time, sulfuric acid reacts with the complex compound and washes out the copper salts from the fibers. The fibers become colorless

It is produced by making cellulose a soluble compound by combining it with copper and ammonia with caustic soda. The solution is passed through a spinneret and the cellulose is regenerated in hardening baths that remove the copper and ammonia and neutralize the caustic soda. Cuprammonium rayon is usually made in fine filaments that are used in lightweight summer dresses and blouses, sometimes in combination with cotton to make textured fabrics with slubbed, uneven surfaces.[3]

The fabric is commonly known by the trade name "Bemberg", owned by the J.P. Bemberg company. The fabric may also be known as "cupro" or "cupra". It is also known as "ammonia silk" on Chinese fashion retail websites.

History edit

Cuprammonium rayon was invented in 1890.[4]

Swiss chemist Matthias Eduard Schweizer (1818–1860) discovered that cellulose dissolves in tetraaminecopper dihydroxide. Max Fremery and Johann Urban developed a method to produce carbon fibers for use in light bulbs in 1897 (the factory closed in 1902).[5] Production of cuprammonium rayon for textiles started in 1899 in the Vereinigte Glanzstoff Fabriken AG in Oberbruch near Aachen.[citation needed][6] An improvement by J. P. Bemberg AG in 1904 made the artificial silk a product comparable to real silk.[7][8]

Properties edit

  • The fibers are very fine[9]
  • It has a soft, silk-like handle (i.e., tactile feel)[9]
  • It has similar properties to cotton. It is different in that the average degree of polymerization is lower and a larger part of this fiber is occupied by amorphous regions, causing cuprammonium rayon to swell[9]
  • It burns rapidly and chars at 180°C[9]
  • On ignition, it leaves behind ash containing copper[9]
  • It can be used to create fabric that is sheer and lightweight and has desirable draping properties[4]

Production edit

Cellulose is dissolved in a [Cu(NH3)4](OH)2 solution and then regenerates as rayon when extruded into sulfuric acid.

References edit

  1. ^ "cuprammonium rayon". Retrieved December 1, 2011.
  2. ^ Burchard, Walther; Habermann, Norbert; Klüfers, Peter; Seger, Bernd; Wilhelm, Ulf (1994). "Cellulose in Schweizer's Reagent: A Stable, Polymeric Metal Complex with High Chain Stiffness". Angewandte Chemie International Edition in English. 33 (8): 884–887. doi:10.1002/anie.199408841.
  3. ^ "Rayon Fiber". Archived from the original on April 6, 2008. Retrieved December 1, 2011.
  4. ^ a b Davidson, Michael W. "Cuprammonium Rayon Fibers". Polarized Light Microscopy Digital Image Gallery. The Florida State University. Retrieved 2 July 2020.
  5. ^ Over 100 years old and still going strong From Glanzstoff (artificial silk) factory to industry park.
  6. ^ Verinigte Glanstoff Fabriken merged with the Nederlandse Kunstzijdefabrieken in 1929 to form the Algemene Kunstzijde Unie, AkzoNobel's predecessor.[citation needed]
  7. ^ Krässig, Hans; Schurz, Josef; Steadman, Robert G.; Schliefer, Karl; Albrecht, Wilhelm; Mohring, Marc; Schlosser, Harald (2002). "Cellulose". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a05_375.pub2. ISBN 978-3527306732.
  8. ^ J. P. Bemberg AG was one of the Vereinigte Glanzstoff-Fabriken which merged into the Dutch based Algemene Kunstzijde Unie (AKU)--AkzoNobel today.[citation needed]
  9. ^ a b c d e "Properties of Cuprammonium Rayon". 2009-05-15. Retrieved December 1, 2011.

External links edit

  1. ^ "Production System".