Methacrylo nitrile

Fig. 24. Sequential three-stage polymerization of methyl methacrylate (MMA), methacrylo-nitrile (MAN), and MAN in CH2CI2 at rt with the methylaluminum porphyrin (1, X=Me)-methylaluminum bis(2,6-di-tert-butyl-4-methylphenolate) (3e) system. GPC profiles of the polymers formed at I The first stage [MMA]o/[l]o=100, 100% conversion Mn= 13,200, Mw/Mn=1.22, II The second stage [MAN]o/[l]o=50, 100% conversion Mn=17,500, Mw/Mn=1.21, and III The third stage [MAN]o/[l]o=50, 100% conversion Mn=20,700, Mw/Mn=1.29...

Monomers with relative reaction rates well below 1 (methacrylo-nitrile and decyl methacrylate). 

In some systems the termination may be extremely slow as compared with the rate of propagation, and then the polymerization may come to the end because the supply of the monomer is exhausted. The termination will eventually take place however, at that time the polymerization is over and consequently such a termination does not contribute to the kinetics of polymerization. Such a situation is most likely to be encountered in an extremely rapid polymerization, e.g. this is claimed to be the case in a polymerization of methacrylo-nitrile proceeding in liquid ammonia and initiated by metalic lithium. 

Economically produced block copolymers containing acrylonitrile or methacrylo-nitrile as the principal component have been prepared that are heat resistant, weath-erable, and oil and flame resistant. These materials were prepared using reversible addition-fragmentation chain transfer polymerization. 

Catalyst Acrylo- nitrile Croto- nitrile Methacrylo- nitrile Dimethyl maleate... 

The rates of radical-monomer reactions are also dependent on considerations of steric effects. It is observed that most common 1,1-disubstituted monomers — for example, isobutylene, methyl methacrylate and methacrylo-nitrile—react quite readily in both homo- and copolymerizations. On the other hand, 1,2-disubstituted vinyl monomers exhibit a reluctance to ho-mopolymerize, but they do, however, add quite readily to monosubstituted, and perhaps 1,1-disubstituted monomers. A well-known example is styrene (Ml) and maleic anhydride (M2), which copolymerize with r — 0.01 and T2 = 0 at 60°C, forming a 50/50 alternating copolymer over a wide range of monomer feed compositions. This behavior seems to be a consequence of steric hindrance. Calculation of A i2 values for the reactions of various chloroethylenes with radicals of monosubstituted monomers such as styrene, acrylonitrile, and vinyl acetate shows that the effect of a second substituent on monomer reactivity is approximately additive when both substituents are in the 1- or cr-position, but a second substituent when in the 2- or /3-position of the monomer results in a decrease in reactivity due to steric hindrance between it and the polymer radical to which it is adding. 

Miscellaneous Rearrangements and Bond Fission Processes. - Methacrylo-nitrile undergoes C-CN bond fission on irradiation at 193 Substitution... 

In this chapter, there are frequent mentions of certain monomers and the polymers derived from them. Abbreviations are used for styrene (STY), methyl methacrylate (MMA), vinyl acetate (VAC), acrylonitrile (AN) and methacrylo-nitrile (MAN). Abbreviations for other materials are specified at the points at which they first appear. 

Through the years other monomers have been investigated. The diene commonly employed is 1,3-butadiene, although isoprene, 2-ethyl butadiene, 2,3-dimethyl butadiene, piperylene, and other substituted dienes have been investigated. The nitrile commonly employed is acrylonitrile. It has been reported that when part of the acrylonitrile is replaced by methacrylo-nitrile or ethacrylonitrile, the cement-making properties of the rubber are improved. Small proportions of a third monomer may also be used in conjunction with the two principal components. Hycar 1072, which employs methacrylic acid as the third monomer, is occasionally used in adhesive applications. Other monomers including ethyl acrylate, methyl methacrylate, styrene, vinylidene chloride, acrylic acid, N-vinyl-2-pyrrolidone, and vinyl acetate have been employed in varying amounts to adjust the adhesive and elastomeric properties. 

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