Rayon

[5] Rayon production involves solubilizing cellulose to allow turning the fibers into required form.

Max Fremery and Johann Urban developed a method to produce carbon fibers for use in light bulbs in 1897.

[12] Production of cuprammonium rayon for textiles started in 1899 in the Vereinigte Glanzstoff Fabriken AG in Oberbruch (near Aachen).

[14][15] English chemist Charles Frederick Cross and his collaborators, Edward John Bevan and Clayton Beadle, patented their artificial silk in 1894.

In Europe, though, the fabric itself became known as "viscose", which has been ruled an acceptable alternative term for rayon by the US Federal Trade Commission (FTC).

[20] The operating name for the fibre inside the Enka organization was "Newcell", and the development was carried through pilot plant scale before the work was stopped.

The basic process of dissolving cellulose in NMMO was first described in a 1981 patent by Mcorsley for Akzona Incorporated[20][22] (the holding company of Akzo).

Cuprammonium rayon has properties similar to viscose; however, during its production, the cellulose is combined with copper and ammonia (Schweizer's reagent).

Due to the detrimental environmental effects of this production method, cuprammonium rayon is no longer being produced in the United States.

The viscose process builds on the reaction of cellulose with a strong base, followed by treatment of that solution with carbon disulfide to give a xanthate derivative.

The use of woody sources of cellulose makes viscose cheaper, so it was traditionally used on a larger scale than the other methods.

It is then dissolved and forced through a spinneret to produce filaments, which are chemically solidified, resulting in fibers of nearly pure cellulose.

[31][32] To prepare viscose, pulp is treated with aqueous sodium hydroxide (typically 16–19% by mass) to form "alkali cellulose", which has the approximate formula [C6H9O4−ONa]n. This material is allowed to depolymerize to an extent.

The rate of depolymerization (ripening or maturing) depends on temperature and is affected by the presence of various inorganic additives, such as metal oxides and hydroxides.

The steps:[30] The lyocell process relies on dissolution of cellulose products in a solvent, N-methyl morpholine N-oxide (NMMO).

[34] Regular rayon has lengthwise lines called striations and its cross-section is an indented circular shape.

Substituting cotton fiber in tires and belts, industrial types of rayon developed a totally different set of properties, amongst which tensile strength and elastic modulus were paramount.

Modal is a genericized trademark of Lenzing AG, used for (viscose) rayon which is stretched as it is made, aligning the molecules along the fibers.

[contradictory] Polynosic fibers are dimensionally stable and do not shrink or get pulled out of shape when wet like many rayons.

[28] Modal is used alone or with other fibers (often cotton or spandex) in clothing and household items like pajamas, underwear, bathrobes, towels, and bedsheets.

[36] The trademarked Modal is made by spinning beech-tree cellulose and is considered a more eco-friendly alternative to cotton, as the production process uses on average 10–20 times less water.

[15][failed verification] Modal and Tencel are widely used forms of rayon produced by Lenzing AG.

Tencel, generic name lyocell, is made by a slightly different solvent recovery process, and is considered a different fiber by the US FTC.

[40] Visil rayon and HOPE FR are flame retardant forms of viscose that have silica embedded in the fiber during manufacturing.

[48] A 2016 study found a discrepancy in the ability to identify natural fibers in a marine environment via Fourier transform infrared spectroscopy.

CanopyPlanet subsequently started publishing a yearly Hot Button report, which puts all the man-made cellulosics manufacturers globally on the same scoring platform.

[8][7][9][31] As of 2016[update], production facilities located in developing countries generally do not provide environmental or worker safety data.

[31] Studies from the 1930s show that 30% of American rayon workers experienced significant health impacts due to carbon disulfide exposure.

[8] During the Second World War, political prisoners in Nazi Germany were made to work in appalling conditions at the Phrix rayon factory in Krefeld.

[57][58] Workers in factories utilizing the viscose process may be exposed to high levels of carbon disulfide, which can cause coronary heart disease, retinal damage, behavioral changes, impaired motor function, and various fertility and hormonal effects.