Polyalkyl-2-cyanoacrylate

Maincent P, Le Verge R, Sado P, Couvreur P, Devissaguet JP (1986) Disposition kinetics and oral bioavailability of vincamine-loaded polyalkyl cyanoacrylate nanoparticles. J Pharm Sci 75 955-958. 

Polyalkyl cyanoacrylates are clear, colorless thermoplastics whose physical properties are roughly equivalent to those of other common thermoplastics such as PMMA or polystyrene. Because the majority of adhesives sold today are based on ethyl cyanoacrylate, the properties of polyethyl cyanoacrylate (PECA) will be discussed in detail, and existing data for other esters will be tabulated. 

With the exception of polycyanoacrylates containing reactive groups such as polyallyl cyanoacrylate, the properties of the other polyalkyl cyanoacrylates are generally similar to those of PECA. Table IV presents the data available for commercially important cyanoacrylates. 

The moisture resistance of cyanoacrylate adhesives, like the heat resistance, is poor, and the problem is particularly apparent on metals. A cyanoacrylate bond responds in several ways to a moist environment. Polyalkyl cyanoacrylates are very susceptible to alkaline hydrolysis, which degrades the molecular weight rapidly (see Section II.F.). Corrosion products generated at the interface may catalyze this hydrolysis. Loss of adhesion due to displacement of the adhesive from the adherend by moisture is a common occurrence with many adhesives. Evidence that this mechanism... 

The first examples of thickened cyanoacrylate adhesives were described by Coover and Shearer in a U.S. Patent. The thickeners cited and claimed were polyalkyl cyanoacrylates, polyacrylates, polymethacrylates, cellulose nitrate, and cellulose organic acid esters, such as cellulose acetate butyrate. Several years later. Wicker and Shearer improved the process for thickening cyanoacrylates. Instead of adding the thickener directly to the monomer, the thickener was first dissolved in a volatile solvent and then added to the ester. The solvent was then vacuum stripped to give the thickened adhesive. The authors claimed that this process gave adhesives having better clarity, better storage stability, and faster cure speed than adhesives prepared by the older method. 

Solvent resistance. Although polyalkyl cyanoacrylates are thermoplastics, they are resistant to frequently encountered low- and medium-polarity organic liquids. 

Emulsions of polyvinyl acetate and polyalkyl acrylates have been used as tub caulking compositions, spackling compounds and as building sealants.22 Acrylic sealants which harden in the presence of powdered iron or copper meet Federal Specifications TT-S-00230C. 27 Liquid monomers, such as polyethylene glycol dimethacrylate and butyl alpha—cyanoacrylate have been used as room temperature curing sealants.22 22. 

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