Cyanoacrylates advantages

These acids can be used alone or as mixtures. It is especially advantageous to use a mixture of liquid and gaseous acids. The gaseous acid will stabilize free monomer in the headspace of a container, while the liquid acid will prevent premature polymerization of the bulk monomer or adhesive. However, it is important to use only a minimum amount of acid, because excess acid will slow initiation and the formation of a strong adhesive bond. It can also accelerate the hydrolysis of the alkyl cyanoacrylate monomer to 2-cyanoacrylic acid, which inhibits the polymerization of the monomer and reduces molecular weight of the adhesive polymer. While carboxylic acids inhibit the polymerization of cyanoacrylate monomer, they do not prevent it completely [15]. Therefore, they cannot be utilized as stabilizers, but are used more for modifying the reactivity of instant adhesives. 

All of the eommereial alkyl eyanoaerylate monomers are low-viseosity liquids, and for some applications this can be an advantage. However, there are instances where a viseous liquid or a gel adhesive would be preferred, sueh as for application to a vertical surface or on porous substrates. A variety of viscosity control agents, depending upon the desired properties, have been added to increase the viscosity of instant adhesives [21]. The materials, which have been utilized, include polymethyl methacrylate, hydrophobic silica, hydrophobic alumina, treated quartz, polyethyl cyanoacrylate, cellulose esters, polycarbonates, and carbon black. For example, the addition of 5-10% of amorphous, non-crystalline, fumed silica to ethyl cyanoacrylate changes the monomer viscosity from a 2-cps liquid to a gelled material [22]. Because of the sensitivity of cyanoacrylate esters to basic materials, some additives require treatment with an acid to prevent premature gelation of the product. 

What is an advantage to using cyanoacrylates at a crash site ... 

Gelatin-resorcin-formaldehyde adhesives (GRF) have been studied 38-40>. These adhesives compared with cyanoacrylates have an advantage in that they join tissues reliably under conditions of a moist operative area and undergo rapid degradation in the organism. The rate of curing is adjusted easily by changing the ratio of components. 

The viscous isoamyl cyanoacrylate shows the least deterioration of bond strength to bone in an aqueous environment. This material has the further advantage that (1) it may be more suitable for applications where some filling of a gap by the adhesive is required and (2) it is considered to be less toxic than the lower homologues of the 2-cyanoacrylate series. 

Major advantage of this method is that the methyl cyanoacrylate can be instilled by a specially-designed transcervical delivery device (31) by trained paramedical personnel and does not require a surgical procedure. Thus, this method may be attractive to developing countries with serious population problems. 

Moisture-curing adhesives are formulated with resins that react with atmospheric moisture to form a cured polymer. Most of these resins are one-part cyanoacrylates, silicones, or polyurethanes. The key advantage, of course, is their ability to cure without the use of heat or other external form of energy. However, in many cases, several days of ambient exposure are required to achieve full properties since the rate... 

Ethyl cyanoacrylate is a little less polar than methyl cyanoacrylate, and has the ability to wet plastic surfaces more readily, and is a better solvent for plastics. With this added ability to make intimate contact with the surface, the bonds on plastic are stronger with ethyl cyanoacrylate than with the methyl ester. This difference in performance gives rise to the adage that methyl is for metal and ethyl is for everything else. Sometimes this difference can be utilized in reverse to good advantage to avoid stress cracking on such sensitive plastics as polycarbonate and polyacrylate. 

The fourth type of cyanoacrylates presented in Fig. 2 are the alkoxyalkyl esters. Methoxyethyl cyanoacrylate and methoxyisopropyl cyanoacrylate esters have all the desirable properties of the methyl, ethyl, and allyl cyanoacrylates, with the added advantage of low vapor pressure. As a result, these monomers have little or no odor, which makes them popular for use in environments where ventilation is a problem. The low vapor pressure also reduees the fogging of adjaeent parts so often seen with regular cyanoaerylates on damp days, a problem discussed in more detail below. 

N-butyl cyanoacrylate is the most commonly used cerebral AVM embolic material, and is considered by some to be the most effective (Finfante and Wakhloo, 2007). While its drawbacks include tissue adhesiveness and optimization of polymerization time, the main advantage of this material is its permanency. The curative capability of n-BCA, seen both after initial embolization... 

In the aerospace, aircraft, automotive, electrical, instrument, construction and marine industries, among others, modified acrylics offer distinct assembly advantages over high performance epoxies and urethanes, as well as anaerobic structural adhesives and cyanoacrylates. 

Advantages of cyanoacrylate adhesives include rapid curing, solvent-free nature, high bond strength, versatility, solvent resistance and their comprising only one part. 

Further details regarding the advantages and limitations of different adhesives are given in articles already cited and in the articles listed below. Other sources include Refs. [2-4] and works discussed in the Appendix. See also Adhesive classification, Anaerobic adhesives, Cyanoacrylate adhesives. High-temperature adhesives, Rubber-based adhesives. 

Cyanoacrylate adhesives J GUTHRIE Anionic polymerization, additives, applications, advantages and disadvantages... 

The major advantage to the use of Onyx compared with cyanoacrylates is the ease of injection. The catheter should be placed in the same wedge situation as for intranidal glue injection. The injection should be very slow, as well. It may be stopped for... 

It is very difficult to render the smaller screw sizes absolutely immovable with anaerobics. While they will prevent vibration loosening, they cannot necessarily be relied on to prevent removal where permanent assembly and total security is required. In such circumstances cyanoacrylates offer the advantage of literally bonding the parts together, as well as giving a hard mechanical wedge to lock them. 

Recently, inorganic catalysts have been suggested for use as cyanoacrylate initiators, particularly for use in wood bonding. One patent teaches the use of strong bases such as sodium hydroxide in a calcerous binder which provides a chalk-like primer coating for wood. Another patent teaches the use of weakly basic and weakly acidic ionic compounds as wood primers. These last mentioned primers, such as potassium bromide in aqueous ethanol, have the advantage that while they promote rapid polymerization on wood, they do not cause post-cure hydrolysis of the polycyanoacrylate, a problem noted with the strong bases. 

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