Cyanoacrylate

The cyanoacrylate is the name commonly used to name the 2-cyanoacrylate methyl, a very powerful adhesive substance usually sold under the registered trademark Superglue and Krazy Glue .

History

Cyanoacrylate was discovered during the Second world war by seeking a means of replacing the silk of spider in the manufacture of the reticles of sight tubes. It did not solve the problem, because it stuck to all the equipment used to handle it. Later, it was developed in a more useful form by the company Eastman Kodak in 1958. The term is now used to indicate a vast range of Adhésif S based on a similar chemical component.

Properties

In its liquid form, the cyanoacrylate consists of Monomère S of molecules of cyanoacrylates, CH₂=C (CN) COOCH₃ (Empirical formula: C₅H₅NO₂), and has a Molecular weight of 111,1 g/mol. Its Point flash is located at 79 ºC and its Densité is 1,1 compared to water (H₂O).

It is a resin Acrylique which polymerizes in the presence of anions quickly (polymerization starts with an anion igniter, such as the hydroxide, the amines, alcohols,…). In this precise case of anion polymerization, water is enough to start polymerization, the reactional intermediary being stabilized by the presence of the grouping carbonyl and the grouping cyano in alpha of the carbanion. During polymerization, there is formation long and solid chains, uniting surfaces to be stuck.

Another important feature is that the cyanoacrylate adhesive quickly, often in less than one minute, face has a normal joining which obtains its maximum solidity in two hours; and is resistant to water. Accelerating allow to obtain joining into 2 or 3 seconds, at the price of a loss of solidity. Two square centimeters of surface of joining easily support a weight higher than a ton.

The Acetone (which one finds in the solvent for nail varnish), is a solvent easily available, able to soften the polymerized cyanoacrylate.

Use

Cyanoacrylate is a tough Adhésif, particularly when it is used to stick nonporous materials. Thus it is very effective to stick body fabrics, and while this effect can be a harmful effect, (or even dangerous), it was exploited to profit from surgery without Suture S. Its secondary product of polymerization, the acetic Acid , is biocompatible. The cyanoacrylate is used in the orthopedic surgery to stick the metal objects to the bones. For example, artificial kneecaps with the femurs.

The cyanoacrylates are used in criminology for the detection of the digital fingerprints. The Colle liquid is vaporized and the vapor passed on the objects suspectés to have digital fingerprints. The negligible water traces cause the polymerization of the vapor, which, hardened, form a solid version of the print, which is made much more visible and robust.

The cyanoacrylates are often used to assemble prototype S of Circuit electronic S (see Wire wrap) (Cablage), model reduced, to block Boulon S or nut S in Mécanique.

The cyanoacrylate is also used as method of revelation of digital trace within the framework of the scientific police. Heated in a closed tank, in which mist is diffused, the cyanoacrylate sets on all the paroies and reveals the digital drawings left by the contact of the skin. This trace is photographed and transmitted to the automatic file of the digital fingerprints. It then makes it possible to identify individuals by comparison of the drawing digital or palmar.

Synonym

alpha-cyanoacrylate of methyl
MCA
Mécrylate
Mécrilate

See too

Adhesive

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