rayon

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rayon,

synthetic fibers made from cellulosecellulose,
chief constituent of the cell walls of plants. Chemically, it is a carbohydrate that is a high molecular weight polysaccharide. Raw cotton is composed of 91% pure cellulose; other important natural sources are flax, hemp, jute, straw, and wood.
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 or textiles woven from such fibers; more rayon is manufactured than any other synthetic fiber. The name was adopted (1924), in preference to "artificial silk," by the U.S. Dept. of Commerce and various commercial associations. As early as 1665 the English naturalist Robert Hooke had suggested the possibility of making artificial silk, but the first artificial textile fiber was produced in 1884 by a French scientist, Hilaire de Chardonnet, and was manufactured by him in 1889. Unpopular at first because it was too lustrous and laundered poorly, it has been steadily improved. Cellulose, originally from cotton linters but now chiefly from wood pulp, washed, bleached, and pressed into sheets, is dissolved by chemicals, then forced under pressure through minute holes in a metal cap (spinneret), emerging as filaments that unite to form one continuous strand solidified by passage through a suitable liquid or warm air. The spinning solution may be forced through a larger orifice or slit to produce a monofilament, a ribbon, or a sheet. Filaments are doubled and twisted into smooth, silklike yarns or cut into staple lengths and spun. Spun rayon can be treated to simulate wool, linen, or cotton. There are four methods of manufacturing rayon, using different materials and processes. In the nitrocellulose process developed by Chardonnet, no longer of commercial importance, cellulose is treated with nitric and sulfuric acids. In the viscose processviscose process
, method widely used for the commercial preparation of rayon. Cellulose, prepared from either wood pulp or, less commonly, cotton linters, is treated with sodium hydroxide (an alkali) and then with carbon disulfide, the resulting product being a substance called
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 discovered in 1892, it is treated with carbon disulfide, then dissolved in caustic soda, forced through a spinneret, and hardened in sulfuric acid. Viscose rayon is the most important type commercially, being used in most kinds of wearing apparel, furniture fabric, and carpets. For cuprammonium rayon, the cellulose is dissolved in copper oxide and ammonia, forced through holes larger than the intended diameter, then, by a process known as stretch spinning, is elongated and twisted under tension to yield a very fine, strong yarn used for sheer fabrics and hosiery. Rayon produced by these three methods is classified as regenerated, since the final product, like the original material, is cellulose. The fourth type, saponified acetate rayon, originated in England in 1918, is an acetate derivative of cellulose made by steeping cellulose in acetic acid, then treating it with acetic anhydride. Acetate rayon is more resistant to stains and creasing, is plasticized by heat, and requires special dyes, thus allowing two-tone effects with a single dye when acetate is combined with other fibers. An acetate filler is used to make shatterproof glass.

rayon

[′rā‚än]
(textiles)
A fiber made from regenerated cellulose by the viscose or cuprammonium process.

rayon

Continuous-filament yarn composed of regenerated cellulose; similar in chemical structure to natural cellulose fiber but contains shorter polymer units; usually made by the viscose process.

rayon

1. any of a number of textile fibres made from wood pulp or other forms of cellulose
2. any fabric made from such a fibre
References in periodicals archive ?
Develop a monitoring and performance evaluation procedure for LED in oblast and rayons.
From its very beginning, EDP heavily relied on cooperation with the local governments and, in many cases, its activities in pilot rayons were very much dependent either on the political situation or on personal cooperation of certain government officials.
In the SEP planning area, an examination is made of: the working relationships between government (oblast and rayon) departments involved in LED and the coordination of LED efforts between the public and private sector; pilot rayon SEP planning: local economic data collection and analysis.
In one rayon, EDO team-members assisted in the analysis of the newspaper questionnaire on local economic needs.
This change came about when people saw there was an opportunity to do something, get information, ask questions, and knowing there were regular meetings, and a longer-term commitment to LED in the rayon.
Local area economic data (not collected by the Oblast) need to be (and was) collected at the rayon level.
Negotiations have been made with the oblast to obtain the necessary rayon data that they have collected.
This version reflects the unique historic, economic, land-use and cultural situation of the rayon.
The working relationship among various oblast and rayon departments associated with economic development is developing.
In SEP, more local volunteers need to be recruited from community and business organizations: for example, to assist in doing LED, EDO's roles/functions such as data-gathering surveys, distributing promotional materials on their travels outside their rayon, and abroad.
The Oblast needs to give formal recognition and to legitimize LED and SEP in oblast and rayon.
As well, an agreement has to be reached between the Oblast Statistics Department and rayon LED Departments on who collects what data (to avoid duplication) and on the sharing and exchanging of data.