Acrylonitrile-vinyl acetate

The monomer pair, acrylonitrile—methyl acrylate, is close to being an ideal monomer pair. Both monomers are similar in resonance, polarity, and steric characteristics. The acrylonitrile radical shows approximately equal reactivity with both monomers, and the methyl acrylate radical shows only a slight preference for reacting with acrylonitrile monomer. Many acrylonitrile monomer pairs fall into the nonideal category, eg, acrylonitrile—vinyl acetate. This is an example of a nonideality sometimes referred to as kinetic incompatibiUty. A third type of monomer pair is that which shows an alternating tendency. 

The photo-induced process of modification of cellulose and its derivatives was reported by Geacintov and coworkers [67,68]. Thus, acrylonitrile, vinyl acetate, styrene, MMA, and the binary system of styrene and AN were grafted onto cellulose and cellulose derivatives. In... 

The permeability of a number of gases through acrylonitrile-vinyl acetate (PAN-PVAc) and acrylonitrile-styrene (PAN-PS) copolymers has been studied over a wide range of composition Calculations on the basis of Eq. (30), or of the (empirical) Higuchi equation 100)... 

In the late fifties Regie Nationale des Usines Renault (86) described the preparation of allyl ethers through reaction of alkali cellulose with allyl halides in carbon tetrachloride or benzene. With products having degrees of substitution between 0.2 to 0.8 graft copolymerization could be achieved when activated by pretreatment with air or ozone or by initiation with peroxide catalysts with styrene, acrylonitrile, vinyl acetate, or acrylates. 

Fig. 22a-h. Glass transition temperature versus composition of copolymers methyl methacrylate + styrene (a) styrene + methyl acrylate (b) acrylonitrile + styrene (c) vinyl chloride + methyl acrylate (d) methyl methacrylate + vinyl chloride (e) acrylonitrile + butadiene (f) acrylonitrile + vinyl acetate (g) a-methyl styrene + acrylonitrile (h). Experimental points obtained at low conversions from various publications, are compared to the theoretical plots calculated according to Eqs. (7.1) within the framework of the terminal model [18]... 

In this synthesis, the reactivity of monomers M decreases in the classic order methyl acrylate > MMA acrylonitrile vinyl acetate > Sty, and DPn values increase linearly with the monomer conversion. Moreover, molecular weights range from 9000 (styrene) to 70000 (methyl acrylate) and the yields are quite high after only 3 h (ca. 90%) [230,231]. In addition, the authors observed that the initial value of DPn decreases with increase in the concentration of xanthogen disulfide [TX], an observation in agreement with the following kinetic equation ... 

Preparation of grafted starches on synthetic polymers. Ce salts are used to oxidize starch and generate free radicals that react with certain monomers (methyl methacrylates, acrylonitrile, vinyl acetate, acrylamide, etc.)... 

As various organic monomers, such as acrylamide, acrylonitrile, vinyl acetate, maleic acid and styrene, can polymerize at the same time as forming inorganic nanomaterials, various kinds of polymer-inorganic nanocomposites can be prepared at room temperature by a y-irradiation synthesis method. 

In some cases reactive alkenes can be polymerized with Kolbe radicals as initiators, e.g. styrene, acrylonitrile, vinyl acetate, methyl acrylate, acrylic acid, acrylamide or vinyl chloride. - The addition of Kolbe radicals to pyridine, benzotrifluoride or benzonitrile affords only low yields. 

Monomer (M2) (Reference) Styrene Methyl methacrylate Acrylonitrile Vinyl acetate Vinyl chloride... 

Novel iron carbonyl monomer, r)4-(2,4-hexadien-l-yl acrylate)tricarbonyl-iron, 23, was prepared and both homopolymerized and copolymerized with acrylonitrile, vinyl acetate, styrene, and methyl methacrylate using AIBN initiation in benzene.70,71 72 The reactivity ratios obtained demonstrated that 23 was a more active acrylate than ferrocenylmethyl acrylate, 2. The thermal decomposition of the soluble homopolymer in air at 200°C led to the formation of Fe203 particles within a cross-linked matrix. This monomer raised the glass transition temperatures of the copolymers.70 The T)4-(diene)tricarbonyliron functions of 23 in styrene copolymers were converted in high yields to TT-allyltetracarbonyliron cations in the presence of HBF4 and CO.71 Exposure to nucleophiles gave 1,4-addition products of the diene group.71... 

In summary, Table 3 presents a certain number of phenolic inhibitors that are used either during the process or storage of the main monomers including vinyl monomers such as acrylonitrile, vinyl acetate or acrolein. 

In the early work of Norrish, [29] it has been demonstrated that upon irradiation poly(methyl vinyl ketone) in conjunction with acrylonitrile, vinyl acetate, or methyl methacrylate in dioxane solution went through a-cleavage and yielded graft and homopolymers of the corresponding monomers according to the mechanism outlined in Scheme 13.10. The presence of acetaldehyde and methane in the polymerization medium supported the proposed cleavage mechanism. The initial... 

A further method of forming a Pb-C bond is by hydroplumbation of unsaturated organic compounds.481 For example, tributyllead hydride adds, even at 0° in absence of a catalyst, to terminal olefins such as acrylonitrile, vinyl acetate, and styrene ... 

Most acrylonitrile monomer pairs fall into the nonideal category. One such nonideal monomer pair is acrylonitrile-vinyl acetate, with R =4.05 and f 2 = 0.061 at 60°C. This is an example of a nonideality sometimes referred to as kinetic incompatibility. Acrylonitrile, because of the potential resonance stabilization offered by the nitrile group, is a reactive monomer but a relatively unreactive radical. On the other hand, vinyl acetate offers little possibility for resonance stabilization, so it can be categorized as a relatively unreactive monomer but highly reactive radical. The effect, shown in Table 12.6, is that the reaction between the very reactive acrylonitrile monomer with the highly reactive vinyl acetate radical has an extremely high rate constant. 

FIGURE 12.3 Incremental copolymer composition versus monomer composition for three commonly observed reaction patterns acrylonitrile-vinyl acetate (AN-VA, = 4.05/0.061) acrylonitrile-... 

FIGURE 12.4 Illustration of drift in copol rmer composition with conversion in a batch reactor for two commercially important comonomer pairs. VA content in copolymer increases sharply with conversion in acrylonitrile-vinyl acetate copol merization (i i/iJ2 = 4.05/0.061) and content of MA in copolymer changes very little with conversion in acrylonitrile-methyl acrylate copolymerization (i i/i 2=l 02/0.70). 

FIGURE 12.17 Dependence of the polymer melting point on water content for acrylonitrile-vinyl acetate copolymers. (From Frushonr, B.G., Polym. Bull. 7, 1, 1982.)... 

The NMR method has been extremely successful when applied to sequencing addition copolymers with carbon atom backbone, such as ethylene, propylene, butadiene, acrylonitrile, vinyl acetate, methyl methacrylate, styrene, methylstyrene, vinyl chloride, vinyl fluoride (in this case, F-NMR can be used). " Condensation copolymers such as polyurethanes, polyesters, and polyamides have been analyzed by and NMR. cellent reviews have appeared on this topic, the literature on the subject is always growing, and the instrumental progress is fast. ... 

The pyrolysis derivatization approach may also be used. THM results in the formation of dimethyl terephthalate when PET fibers are subjected to the procedure. Tetrabutyl ammonium hydroxide may be used to replace TMAH in the reaction to confirm the presence of vinyl acetate in acrylonitrile-vinyl acetate copolymer acrylic fibers. The derivatized product is butyl acetate. ... 

Espinoza-Gomez and Lin prepared negatively charged hydrophilic UF membranes from the blend of acrylonitrile-vinyl acetate (CP16) and acrylonitrile-vinyl acetate-sodium p-sulfophenyl methallyl ether (CP24) [49]. The compositions of membrane casting solutions for nine different membranes are summarized in Table 5.17. 

Cetiner S., Sen S., Arman B., and Sarac A S., Acrylonitrile/vinyl acetate copolymer nanofibers with different vinylacetate content, j. Appl. Polym. Set, 2013,127,5,3830-3838, D01 10.1002/app.37690. 

Transfer agent Styrene Acrylonitrile Vinyl acetate... 

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