Vinylidene cyanide

It has been shown52 that under similar conditions reduction of the nitrile groups in cellulose ethyl cyanate and of those in the copolymer of vinylidene cyanide with vinyl acetate, proceed simultaneously in two directions with the formation of aldehyde and amine groups. g+ g ... 

Polymer Solvent. Sulfolane is a solvent for a variety of polymers, including polyacrylonitrile (PAN), poly(vinylidene cyanide), poly(vinyl chloride) (PVC), poly(vinyl fluoride), and polysulfones (124—129). Sulfolane solutions of PAN, poly(vinylidene cyanide), and PVC have been patented for fiber-spinning processes, in which the relatively low solution viscosity, good thermal stability, and comparatively low solvent toxicity of sulfolane are advantageous. Powdered perfluorocarbon copolymers bearing sulfo or carboxy groups have been prepared by precipitation from sulfolane solution with toluene at temperatures below 300°C. Particle sizes of 0.5—100 Jim result. 

New terpolymers of vinyl acetate with ethylene and carbon monoxide have been prepared and their uses as additives to improve the curing and flexibility of coating resins, eg, nitrocellulose, asphalt, phenolics, and polystyrene, have been described (130—132). Vinyl acetate and vinylidene cyanide form highly alternating copolymers. 

In addition to these monomers, vinylidene cyanide polymerizes very readily anionically (15). Even traces of the relatively weak base water being sufficient to cause a violent polymerization... 

Spontaneous 1 1 copolymerization has been noted when sulfur dioxide was bubbled through bicycloheptene at —40°C. (88), when isobutylene was bubbled through methyl a-cyanoacrylate (54), when 1,3-dioxole was mixed with maleic anhydride (17), and when vinylidene cyanide was mixed with styrene (20), the latter reactions at room temperature. None of these monomers undergoes homopolymerization under the same experi-... 

Darvan Vinylidene cyanide-vinyl acetate copolymer Celanese... 

The synthesis of anion-exchange resins from acrylonitrile — SDVB copolymer has been reported The copolymer beads are converted to imino ester form by passing dry hydrogen chloride gas into a slurry of the beads in anhydrous methanol at 5 °C. These beads, after washing with anhydrous methanol, are refluxed with a mixture of ethylene diamine and anhydrous methanol. The resin thus synthesized has a capacity of 5 meq/g in Cl" form. Other diamines used for the synthesis of such type of resins are aminoethanolamine, neopentyldiamine, and trimethylenediamine Other monomers which are used for the synthesis of polymer matrices are methyl-acrylonitrile, vinylidene cyanide, cyanoalkyacrylates, and methacrylates, o-, m-, and />-cyanostyrene, 1-cyanobutadiene, 2-cyanobutadiene, methyl, ethyl, propyl,... 

Very recently the spontaneous, simultaneous homopolymerization of vinylidene cyanide and cyclic ethers including THF has been reported [105]. Polymerizations were initiated via a donor—acceptor complex but further investigation of the mechanism of initiation is continuing. It is still too early for kinetics to have been reported but they should be interesting when they do come. 

Similar to vinyl derivatives, a number of substituted vinylidene polymers are used in practice. Some of these polymers are part of classes of polymers such as halogenated polyolefins and were discussed separately (see Section 6.3 and 7.5). One example of polymer that can be indicated here is poly(vinylidene cyanide). Its pyrolysis generates a high yield of monomer [42],... 

Where both donor and acceptor molecules are vinyl monomers then the generation of radical ions might be expected to polymerize both species. This appears to be so [see reaction (9)] when unsaturated ethers, such as / -dioxene, dihydropyran, ethyl vinyl ether, isopropyl vinyl ether, and ketene diethylacetal, are each mixed with vinylidene cyanide. Cycloadducts are also important... 

Alkyl cyanoacrylates are used extensively as instant adhesives and are grouped with vinylidene cyanide, methylene malonates, and a-cyanosorbates at the top of the anionic reactivity scale. As well as readily polymerizing in the presence of conventional anionic initiations such as Bu"Li, they also react readily with tertiary amines and phosphines. Pepper and Johnstonhave examined the catalytic action of triethylphosphine and pyridine at —78 °C in tetrahydrofuran. The former initiator appears to add rapidly and irreversibly to monomer to yield a conventional living anionic polymerization. With pyridine, however,... 

Thus the relatively weak sodium methoxide (NaOCHs) can polymerize acrylonitrile, which has a strong electronegative substituent (-CN). Vinylidene cyanide carries two —CN groups on the same carbon atom and can be polymerized even by weaker bases like water and amines. Polymerization of nonpolar monomers such as conjugated olefins, however, requires initiation by very strong bases like metal alkyls. 

Only monomers with pronounced electron acceptor properties can polymerize in water (e. g. derivatives of nitrostyrenes, cyanocrylates, vinylidene cyanide). Generally, only oligomers are formed. 

This is achieved by using monomers of the corresponding nature (nitroethylene and vinylidene cyanide are polymerized only anionically, whereas acrylonitrile and methyl methacrylate polymerize by both anionic and free-radical mechanisms) and by carrying out polymerization in solvents whose molecules contain electron-donating groups (atoms) or an unshared electron pair (dimethyl formamide, tri ethyl amine, isopropylamine, tetrahydrofuran, acetone, ethylpropyl ketone, etc.). 

In a paper devoted to the investigation of radical co-polymerization of vinylidene cyanide with a variety of monomers, an unusual autocatalytic behavior was reported for the pair vinylidene cyanide - vinyl ether251. The authors suggested a possible mutual co-initiation of anionic polymerization of vinylidene cyanide, inducing a cationic polymerization mode of vinyl ether. 

Vinylidene cyanide is much more rapidly polymerized than the cyclic ether, as shown in Fig. 32. Furthermore, it precipitates as it is formed, hurrying its anionically growing end-group in the resulting gel and making it inaccessible to the cationically growing polyether. Hence, these two polymerizations proceed in different phases and, to a great extent, at different times. 

Fig. 32. Rates of disappearance of vinylidene cyanide (VC) and tetrahydrofuran (THF) in spontaneous polymerization of their 1 1 mixture of20°C...

Darvatt . Vinylidene cyanide-vinyl acetate copolymer Parian Travis. Methylenemalononitrile copolymer with vinyl acetate contg about equal parts of each component. Polymerization of vinylidene cyanide with vinyl acetate Gilbert et al. J. Am. Chem. Soc. 78, 1669 (1956) Gilbert, Miller, U.S. pat. 2,615,866 and Sayre, U.S. pat. 2,975,-158 (1952, 1961, hoth to B. F. Goodrich). Review R W. Moncrieff, Man-Made Fibres (John Wiley, New York, 4th ed., 1963) pp 488-494. Approximate structure ... 

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