Copolymerization of acrylonitrile

Homogeneous GopolymeriZation. Nearly all acryhc fibers are made from acrylonitrile copolymers containing one or more additional monomers that modify the properties of the fiber. Thus copolymerization kinetics is a key technical area in the acryhc fiber industry. When carried out in a homogeneous solution, the copolymerization of acrylonitrile foUows the normal kinetic rate laws of copolymerization. Comprehensive treatments of this general subject have been pubhshed (35—39). The more specific subject of acrylonitrile copolymerization has been reviewed (40). The general subject of the reactivity of polymer radicals has been treated in depth (41). 

Nitrile Rubber. Nitrile mbbers are made by the emulsion copolymerization of acrylonitrile (9—50%) and butadiene (6) and designated NBR. The ratio of acrylonitrile (ACN) to butadiene has a direct effect on the properties on the nature of the polymers. As the ACN content increases, the oil resistance of the polymer increases (7). As the butadiene content increases, the low temperature properties of the polymer are improved (see Elastomers, SYNTHETIC-NITRILE RUBBER). 

Graft copolymerization of acrylonitrile with various vinyl comonomers such as methyl acrylate, ethyl acrylate, vinyl acetate, and styrene onto cellulose derivatives using ceric ion was studied [24]. The results showed that... 

Scheme 11 Catalyst deactivation routes in copolymerizations with polar olefins a P-elimination of a leaving group to afford allylic or dimeric species, b poisoning by N-complexation in the attempted copolymerization of acrylonitrile...

Heterogeneous combustion, 7 449-454 Heterogeneous copolymerization of acrylonitrile, 11 203—204 with VDC, 25 698-699 Heterogeneous enzyme systems, 10 255-256 Heterogeneous gas-solid catalytic reactions, 21 340-341 Heterogeneous Ideal Adsorbed Solution Theory (HIAST), gas separation under, 1 628, 629... 

Homogeneous copolymerization, of acrylonitrile, 2 2 202-203 Homogeneous difunctional initiators, 24 246... 

ABS Polymer produced by the copolymerization of acrylonitrile, butadiene, and styrene. 

The graft copolymerization of acrylonitrile onto polystyrene was attempted using benzoyl peroxide, di-/-butylperoxide, and 2,5-dimethyl-2,5-di-(/-butylperoxy)hexane as initiators. In all cases no increase in mass of the polystyrene was observed. Attempts were also made to test whether the polystyryl radical was ever formed by combining the initiator and the polymer or the initiator, polymer and a nitroxide radical trap. In the first case the formation of a radical must lead to cross-linking of the polymer and in the second case the polystyryl radical will be trapped by the nitroxide. ... 

T., 1. Xue and C. A Wilkie, Graft copolymerization of acrylonitrile onto polystyrene,./. Polym. Sci. Part... 

An anionic technique by indirect grafting was proposed for N-metallation of Nylon by Yamaguchi (153-155), in which alcali metals dissolved in liquid ammonia displace the amidic hydrogen atoms. Nylon derivatives and graft copolymers can be synthetized from the N-metallated Nylon (153). For ethylene oxide as grafting monomer, the metallated fibers were soaked in a tetrahydro-furan solution of the monomer, at 60° C (154). Methyl methacrylate is grafted on Nylon with a conversion over 90% by this technique (155). Other procedures involve the use of sodium methoxide in methanol solution and subsequent anionic graft copolymerization of acrylonitrile in a tetrahydrofuran solution (156). 

The graft copolymerization of acrylonitrile and of styrene onto regenerated celluloses, such as viscose rayon and cellophane, and onto cellulose acetate has been investigated by Pikler, Suta, and Alfoeldi (68) and by Alfoeldi and Pasteka (69). In both studies the authors used ozonized substrate for initiating the graft copolymerization. 

Graft Copolymerization of Acrylonitrile onto Bamboo Using IR Spectroscopic Technique as a Probe... 

The effect of ceric ion concentration on the graft copolymerization of acrylonitrile onto bamboo is shown in Figure 3 As can be seen the grafting percentage increases to a maximum and then decreases with further increase in the concentration of the initiator. The optimum concentration of the initiator was found at around 0.15 M. 

Figure 6. Effect of ceric ion concentration on the graft copolymerization of acrylonitrile onto holocellulose. Key A, using gravimetric method O, using spectroscopic method.

The results of the present study on the graft copolymerization of acrylonitrile onto bamboo can be summarized as follows ... 

However, the ratio 22/ 21 is the reactivity ratio f2 for copolymerization of acrylonitrile with methacrylonitrile, so that... 

An analogous situation would hold in the copolymerization of acrylonitrile with vinylidene chloride in the presence of zinc chloride (32). 

Such a procedure was successfully employed for the copolymerization of acrylonitrile with methyl methacrylate [275] or methacrylic add [276]. In the former case, the copolymerization was carried out at 40 °C in bulk (I) and in tetra-... 

Table 64 Values of reactivity ratios calculated according to Eqs. (6.10) and (6.11) used in Ref. [276] to treat the data on products of copolymerization of acrylonitrile with methacrylic acid in solution of dimethyl sulfoxide (I) and its equimolar aqueous mixture (III The conversion in all cases does not exceed 7%...

Pichot et al. applied the spin-trapping technique to study the copolymerization of acrylonitrile with vinyl chloride or vinyl acetate [256]. Macroradicals terminated by the latter two units are trapped preferentially. The authors also noted suppression of cyclization by the spin-trapping agent cyclization is otherwise very common in acrylonitrile copolymerizations. 

Addition of anionic nucleophiles to alkenes and to heteronuclear double bond systems (C=0, C=S) also lies within the scope of this Section. Chloride and cyanide ions are effieient initiators of the polymerization and copolymerization of acrylonitrile in dipolar non-HBD solvents, as reported by Parker [6], Even some 1,3-dipolar cycloaddition reactions leading to heterocyclic compounds are often better carried out in dipolar non-HBD solvents in order to increase rates and yields [311], The rate of alkaline hydrolysis of ethyl and 4-nitrophenyl acetate in dimethyl sulfoxide/water mixtures increases with increasing dimethyl sulfoxide concentration due to the increased activity of the hydroxide ion. This is presumably caused by its reduced solvation in the dipolar non-HBD solvent [312, 313]. Dimethyl sulfoxide greatly accelerates the formation of oximes from carbonyl compounds and hydroxylamine, as shown for substituted 9-oxofluorenes [314]. Nucleophilic attack on carbon disulfide by cyanide ion is possible only in A,A-dimethylformamide [315]. The fluoride ion, dissolved as tetraalkylammo-nium fluoride in dipolar difluoromethane, even reacts with carbon dioxide to yield the fluorocarbonate ion, F-C02 [840]. 

Borbely JD, Graham D, Hill DJT, Lang AP, Munro P and O Donnell JH (1991) NMR studies of copolymerizations of acrylonitrile. Prog Pac Polym Sci, Proc Pac Polym Con/1 237-48. 

Plessier C, Gaupta B, and Chapiro A. Modification of polypropylene fiber by radiation-induced graft copolymerization of acrylonitrile monomer. J. Appl. Polym. Sci. 1998 69 1343-1348. 

In copolymerization of acrylonitrile and styrene, 1-5% of added nitrogen base may promote MW reduction.297 Several bases including pyridine, triethylamine, and DABCO convert CCT catalysts into Cl catalysts in the polymerization of MMA,298 suggesting that the bases are proton acceptors converting LCo-H or LCo-R into a 7r-complex of LCo1 with monomer. Figure 9 shows the dependence of the... 

The copolymerization of acrylonitrile and acrylamide occurs by a free radical mechanism with an initial stage of initiation resulting in free radicals. FeSO, NaS O and (NH )jSjOj are used as initiators. The following reagents were added to obtain copolymer containing 20% acrylamide mL, acrylonitrile-12 g, acrylam-... 

The polarity of any species is independent of whether it is in monomer or radical form for the free radical is a neutral entity. Thus assuming that the above types of polarization are also possible with radicals, one can understand that a chain end at which there happens to be a structural unit with an electron-withdrawing substituent, prefers a monomer with an electron-donating substituent and vice versa. Such consideration of polarity explains that, for example, acrylonitrile forms statistical copolymers with methyl acrylate (rir2 = 1.26), while copolymerization of acrylonitrile with ethyl vinyl ethers leads to alternating structures (r r2 == 0.04). 

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