mordant

1. 1. Bitingly sarcastic: mordant satire.
   2. Incisive and trenchant: an inquisitor's mordant questioning.
2. Bitingly painful.
3. Serving to fix colors in dyeing.

1. A reagent, such as tannic acid, that fixes dyes to cells, tissues, or textiles or other materials.
2. A corrosive substance, such as an acid, used in etching.

To treat with a mordant.

[French, from Old French, present participle of mordre, to bite, from Vulgar Latin *mordere, from Latin mordēre.]

A substance or combination of substances that facilitates the fixing of a dye to a fiber. A mordant enables the production of a more permanent and often deeper color. Metallic salts or hydroxides are most frequently used as mordants.

Certain mordants act directly on the fiber, making it more susceptible to the dye. Fabrics are then pretreated with the mordant before exposure to the dye. Other mordants function through the formation of a complex with the dye. The complex acts as the dyeing agent. Mordant and dye in this case are exposed simultaneously to the fabric. See also Dye.

adjective

So sharp as to cause mental pain: acerbic, acid, acidic, acrid, astringent, biting, caustic, corrosive, cutting, mordacious, pungent, scathing, sharp, slashing, stinging, trenchant, truculent, vitriolic. See attack/defend, respect/contempt/standing.

Definition: caustic
Antonyms: uncritical, vague

1. a substance capable of intensifying or deepening the reaction of a specimen to a stain.
2. to subject to the action of a mordant before staining.

Not to be confused with mordent.

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A mordant is a substance used to set dyes on fabrics by forming an insoluble compound with the dye.^[1] It may be used for dyeing fabrics, or for intensifying stains in cell or tissue preparations. A mordant is either inherently colloidal or produces colloids and can be either acidic or alkaline.

Common mordants

Mordants include tannic acid, alum, chrome alum, sodium chloride, and certain salts of aluminum, chromium, copper, iron, iodine, potassium, sodium, and tin.

Iodine is used as a mordant to set the first dye in gram stains.

Phosphomolybdic acid is used as a mordant to set light green when staining with Masson's trichrome stain.

Methods

The three methods used for mordanting are:

• Pre-mordanting: The substrate is treated with the mordant and then dyed.
• Meta-mordanting: The mordant is added in the dye bath itself.
• Post-mordanting: The dyed material is treated with a mordant.

The methods have different effects on the shade obtained after dyeing and also on the fastness properties. It also depends upon the dye and the substrate. It is therefore necessary to choose a proper method to get the required shade and fastness by optimization of parameters.

• Cotton:

Since metallic mordants are soluble in water and are loosely held by the cotton fibres, these mordants have to be precipitated on the fabric by converting them into insoluble form, or by first treating the fibres with oil or tannic acid and then impregnating treated fabric with solution of mordant, whereby the metallic mordants are held on to cotton via oil or tannic acid.

• Wool:

Unlike cotton, wool is highly receptive toward mordants. Due to its amphoteric nature wool can absorb acids and bases equally effectively. When wool is treated with a metallic salt it hydrolyses the salt into an acidic and basic component. The basic component is absorbed at –COOH group and the acidic component is removed during washing. Wool also has a tendency to absorb fine precipitates from solutions; these cling to the surface of fibres and dye particles attached to these contaminants result in poor rubbing fastness.

• Silk:

Like wool, silk is also amphoteric and can absorb both acids as well as bases. However, wool has thio groups (-SH) from the cystine amino acid, which act as reducing agent and can reduce hexavalent chromium of potassium dichromate to trivalent form. The trivalent chromium forms the complex with the fibre and dye. Therefore potassium dichromate cannot be used as mordant effectively.

References

1. ^ International Union of Pure and Applied Chemistry (1993). "mordant". Compendium of Chemical Terminology Internet edition.

v • d • e Dyeing Techniques: Batik · Dyeing · Leheria · Mordant · Tie-dye · Kalamkari · Resist Types of dyes: Dyes · Natural · Acid · Reactive · Solvent · Substantive · Sulfur · Vat Traditional textile dyes: Brazilin · Cochineal · Cudbear · Dyewoods · Fustic · Henna · Indigo · Kermes · Logwood · Madder · Polish cochineal · Saffron · Tyrian purple · Weld · Woad History: Trade and use of saffron  · Traditional dyes of the Scottish Highlands Craft dyes: Dylon · Procion

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Dansk (Danish)
adj. - bidende (f.eks. sarkasme), skarp, ætsende
n. - bejdse(farvestof)
v. tr. - behandle med bejdse

Nederlands (Dutch)
beits, etsvloeistof, bijtend, etsend, snijdend

Français (French)
adj. - mordant, caustique
n. - pincé
v. tr. - (Tech) mordancer

Deutsch (German)
adj. - beißend, beizend
n. - Beize
v. - beizen

Ελληνική (Greek)
adj. - δηκτικός, καυστικός
n. - στυπτήριο, στύμμα, στερεωτικό βαφής
v. - στυπτηριάζω

Italiano (Italian)
mordente

Português (Portuguese)
adj. - mordaz, corrosivo
n. - mordente (m)
v. - aplicar mordente a

Русский (Russian)
язвительный, вызывающий разрушение, травящее вещество

Español (Spanish)
adj. - mordaz, mordiente, cáustico
n. - mordiente, mordente, sustancia fijadora
v. tr. - tratar con sustancia fijadora, fijar

Svenska (Swedish)
adj. - bitande, skarp, frätande, betnings-, bindnings-
n. - etssyra, betningsmedel, fixermedel
v. - fräta

中文（简体）(Chinese (Simplified))
尖酸的, 有腐蚀性的, 辛辣的, 金属腐蚀剂, 金箔粘着剂, 用媒染剂处理

中文（繁體）(Chinese (Traditional))
adj. - 尖酸的, 有腐蝕性的, 辛辣的
n. - 金屬腐蝕劑, 金箔粘著劑
v. tr. - 用媒染劑處理

한국어 (Korean)
adj. - 비판하는, 부식성의
n. - 착색료
v. tr. - 착색료로 처리하다

日本語 (Japanese)
adj. - 皮肉な, 辛辣な, 腐食性の
n. - 媒染剤, 金属腐食剤

العربيه (Arabic)
‏(صفه) لاذع (الاسم) حامض كاوي (فعل) يلذع‏

עברית (Hebrew)
adj. - ‮עוקץ, סרקסטי‬
n. - ‮חומר מאכל, צורב או מטהר‬
v. tr. - ‮השתמש בחומר מאכל, צורב או מטהר‬

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