Methyl cyanoacrylates

SYNS ADHERE COAPT a-CYANOACRYLIC ACID METHYL ESTER 2-CYANOACRYLIC ACID, METHYL ESTER CYANOLIT E. STMAN 910 EASTMAN 910 ADHESIVE EASTMAN 910 MONOMER MECRILAT MECRYLATE METHYL CYANOACRYLATE METHYL 0-CYANOACRYLATE SUPER GLUE... 

Synonyms/Trade Names Mecrylate, Methyl cyanoacrylate, Methyl a-cyanoacrylate, Methyl ester of 2-cyanoacrylic acid ... 

Methyl cyanoacrylate. See Methyl 2-cyanoacrylate Methyl 2-cyanoacrylate CAS 137-05-3... 

Synonyms ACC Acrylic acid, 2-cyano-, methyl ester 2-Cyanoacrylic acid, methyl ester a-Cyanoacrylic acid, methyl ester 2-Cyano-2-propenoic acid, methyl ester Mecrylate Methyl cyanoacrylate Methyl-a-cyanoacrylate Methyl 2-cyano-2-propenoate 2-Propenoic acid, 2-cyano-, methyl ester Empirical C5H5NO2 Formula CH2 C(CN)COOCH3 Properties Colorless to si. yel. clear liq. acrid odor sol. 1-10 mg/ml in DMSO sol. < 1 mg/ml in water, 95% ethanol, acetone m.w. 111.10 sp.gr. 1.1044 (27/4 C) b.p. 47-49 C (1.8 mm) flash pt. 78.9 C... 

Superglue is made by the on-the-spot polymerization of methyl a-cyanoacrylate (methyl 2-cyanopropenoate) with a little water or base. Draw the structure of the repeating unit. Why is this monomer so susceptible to anionic polymerization ... 

The general structure of cyanoacrylate esters is H2C=C (CN) (COOR). Most cyanoacrylate adhesives are based on either methyl-2-cyanoacrylate or ethyl-2-cyanoacrylates. Methyl cyanoacrylates yield better strengths when bonding metals or other rigid surfaces. In addition, impact resistance is slightly hetter. Ethyl cyanoacrylates are stronger and more durable when bonding rubber or plastic substrates. 

Methyl cyanoacrylate Methyl 2-cyanopropenaote (sometimes cyanomethacrylate)... 

Short-chain cyanoacrylates (methyl, ethyl) are toxic to tissue this is not the case with butyl cyanoacrylate when applied topically. In an experimental model... 

The 2-cyanoacryhc esters have sharp, pungent odors and are lacrimators, even at very low concentrations. These esters can be irritating to the nose and throat at concentrations as low as 3 ppm eye irritation is observed at levels of 5 ppm (13). The TLV for methyl 2-cyanoacrylate is 2 ppm and the short-term exposure limit is 4 ppm (14). Good ventilation when using the adhesives is essential. 

Acryhc stmctural adhesives have been modified by elastomers in order to obtain a phase-separated, toughened system. A significant contribution in this technology has been made in which acryhc adhesives were modified by the addition of chlorosulfonated polyethylene to obtain a phase-separated stmctural adhesive (11). Such adhesives also contain methyl methacrylate, glacial methacrylic acid, and cross-linkers such as ethylene glycol dimethacrylate [97-90-5]. The polymerization initiation system, which includes cumene hydroperoxide, N,1S7-dimethyl- -toluidine, and saccharin, can be apphed to the adherend surface as a primer, or it can be formulated as the second part of a two-part adhesive. Modification of cyanoacrylates using elastomers has also been attempted copolymers of acrylonitrile, butadiene, and styrene ethylene copolymers with methylacrylate or copolymers of methacrylates with butadiene and styrene have been used. However, because of the extreme reactivity of the monomer, modification of cyanoacrylate adhesives is very difficult and material purity is essential in order to be able to modify the cyanoacrylate without causing premature reaction. 

In dry air and in the presence of polymerisation inhibitors methyl and ethyl 2-cyanoacrylates have a storage life of many months. Whilst they may be polymerised by free-radical methods, anionic polymerisation is of greater significance. A very weak base, such as water, can bring about rapid polymerisation and in practice a trace of moisture on a substrate is enough to allow polymerisation to occur within a few seconds of closing the joint and excluding the air. (As with many acrylic monomers air can inhibit or severely retard polymerisation). 

An example of this improvement in toughness can be demonstrated by the addition of Vamac B-124, an ethylene/methyl acrylate copolymer from DuPont, to ethyl cyanoacrylate [24-26]. Three model instant adhesive formulations, a control without any polymeric additive (A), a formulation with poly(methyl methacrylate) (PMMA) (B), and a formulation with Vamac B-124 (C), are shown in Table 4. The formulation with PMMA, a thermoplastic which is added to modify viscosity, was included to determine if the addition of any polymer, not only rubbers, could improve the toughness properties of an alkyl cyanoacrylate instant adhesive. To demonstrate an improvement in toughness, the three formulations were tested for impact strength, 180° peel strength, and lapshear adhesive strength on steel specimens, before and after thermal exposure at 121°C. 

Synthetic polymers can be classified as either chain-growth polymen or step-growth polymers. Chain-growth polymers are prepared by chain-reaction polymerization of vinyl monomers in the presence of a radical, an anion, or a cation initiator. Radical polymerization is sometimes used, but alkenes such as 2-methylpropene that have electron-donating substituents on the double bond polymerize easily by a cationic route through carbocation intermediates. Similarly, monomers such as methyl -cyanoacrylate that have electron-withdrawing substituents on the double bond polymerize by an anionic, conjugate addition pathway. 

Generation and deazetization of specifically dideuterated azo compound 22 in the presence of methyl (Z)-3-cyanoacrylate (T) gave mixtures of symmetric (S) and unsymmetric (U) Diels-Alder-type trapping products, whose ratio depended on the concentration of Larger [T] gave greater proportions of S-products. The... 

Among Michael acceptors that have been shown to react with ketone and ester enolates under kinetic conditions are methyl a-trimethylsilylvinyl ketone,295 methyl a-methylthioacrylate,296 methyl methylthiovinyl sulfoxide,297 and ethyl a-cyanoacrylate.298 Each of these acceptors benefits from a second anion-stabilizing substituent. The latter class of acceptors has been found to be capable of generating contiguous quaternary carbon centers. 

The adhesive marketed under the tradename Superglue contains the monomer methyl a-cyanoacrylate (Fig. 14.5.1). A variety of cyanoacrylates are commercially sold as contact adhesives with the alkyl group -R denoted in Fig. 14.5.2 varying from a methyl group to produce ethyl, isopropyl, allyl, butyl, isobutyl,... 

Figure 14.5.1 The monomer methyl a-cyanoacrylate found in the adhesive marketed under the trademark Superglue. ...

Methyl 3,3-diazido-2-cyanoacrylate, 1824 Methylenebis(3 -nitramino-4-methylfurazan), 2805 1-Methyl-1,2,3-triazole, 1189 Nitrosyl azide, 4766 3-Nitro-l,2,4-triazolone, 0716 Pentazole, 4443... 

Methyl 2-azidobenzoate, 2939 Methyl 3,3-diazido-2-cyanoacrylate, 1824 l.T-Oxybis-2-a/idoc thane. 1604 Phenyl azide, 2271 Phenyldiazidomethane, 2730... 

In many cases, homopolymerization can be initiated by the anion-radicals of the monomers themselves. Of course, such monomers must have pronounced electron affinity (EA) and be stabilized by delocalization of an unpaired electron. Typical examples are represented by the anion-radicals of 1,1-dicyanoethylene (EA = 1.36 eV) and methyl or ethyl 2-cyanoacrylates (EA = 1.08 eV). In all of these anion-radicals, an unpaired electron is primarily localized on C atom of the CH2 segment and characterized by appreciable resonance stabilization (Brinkmann et al. 2002). These anion-radicals are nucleophilic and attack the neutral monomers to initiate polymerization. 

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