Acrylic acid , copolymerization with vinyl acetate

Copolymerization with Vinyl Carboxylic Acids. The acids usually suggested for this method include maleic and fumaric acids and their half esters, crotonic, itaconic, methacrylic, and acrylic acid. The latter three appear to be most generally preferred. On occasion, the amides of these acids are suggested for achieving the same end result (24). Suggested specifically for butadiene-styrene latexes are these acids at about 0.05-10 wt. % based on total monomer. The latex should be adjusted to pH 8-11 (28, 29). For copolymerization with vinyl acetate (2) and acrylic monomers (18) identical acid monomers are suggested. Use of such latexes is claimed to give F/T stable emulsion floor polishes (25) and paints (16). 

Ethylene is copolymerized with many nonolefinic monomers, particularly acrylic acid variants and vinyl acetate, with EVA polymers being the most commercially significant. All of the copolymers discussed in this section necessarily involve disruption of the regular, crystallizable PE homopolymer and as such feature reduced yield stresses and moduli, with improved low-temperature flexibihty. 

High molecular weight and essentially linear polymers, controlled particle size in the case of emulsions, and even polymers with spatially regulated structures are available. Vinyl acetate copolymerizes with many other vinyl monomers. Acrylate esters vinyl chloride and vi-nylidene chloride dibutyl and other dialkyl maleates and fiimarates crotonic, acrylic, methacrylic and itaconic acids vinyl pyrroli-done and ethylene are commercially important comonomers. A monomer that does not combine with vinyl acetate alone may be combined by use of a third monomer. Grafting can be used with monomers such as styrene that do not copolymerize with vinyl acetate. 

Polyethylene made by high-pressure technology is often copolymerized with small amounts of comonomers (e.g., propylene, butene-1, hexene-1, octene-1, vinyl acetate, acrylic acid). The ethylene-vinyl acetate copolymers are used in film, wire or cable coating, and molding applications. Copolymers of ethylene and acrylic acid are treated with compounds of sodium, potassium, zinc, and so forth to form salts attached to the copolymer chain. Such copolymers are often called ionomers. 

Copolymers. Vinyl acetate copolymenzes easily with a few monomers, e g, ethylene, vinyl chloride, and vinyl neodecanoate, which have reactivity ratios close to its own. Block copolymers of vinyl acetate with methyl methacrylate, acrylic acid, acrylonitrile, and vinyl pyrrolidinone have been prepared by copolymerization in viscous conditions, with solvents that are poor solvents for the vinyl acetate macroradical,... 

Vinyl acetate is polymerized in aqueous emulsion and used widely in surface coating and in adhesives. Copolymerized with vinyl esters of branched carboxylic acids and small quantities of acrylic acid, it gives paint latices of excellent performance characteristics. G. C. Vegter found that a coagulum-free latex of very low residual monomer content can be produced from a mixture of an anionic and a nonionic emulsifier according to a specific operating procedure. The freeze/thaw stability of polymeric latices has been investigated by H. Naidus and R. Hanzes. 

Vinyl acetate is relatively inexpensive and is readily copolymerized with vinyl chloride, ethylene, acrylates and methacrylates. The monomer is a colourless, flammable liquid with an initial pleasant odour, which on exposure becomes irritating. One of the major disadvantages of vinyl acetate-based copolymers is their poor hydrolytic and UV stability. This was shown to improve when copolymerized with vinyl esters of versatic acid [18]. Copolymers of vinyl acetate with the vinyl esters of versatic acid have been used in Europe for the last quarter-century. In the US similar monomers were introduced in the past five years, two of which are illustrated in Table 6.1, namely, vinyl pivalate and vinyl neo-decanoate. More details of the copolymerization of these monomers with vinyl acetate is given in Chapter 16. 

The use of acrylic acid not only led to a functionalization of nanoparticles, but also was important as a structure-directing monomer for the formation of nanocapsules. In this case, the hydrophilic groups of the acrylic acid [30] or methacrylic acid [31] resulted in the formation of a nanocapsule structure, instead of Janus-like or even separate nanoparticles. The copolymerization of the functional n-methylol acrylamide with vinyl acetate was found to follow (in batch miniemulsion) the Mayo-Lewis equation, despite huge differences in the solubility of the monomers in the aqueous continuous phase [32]. A functionality of fluori-nated particles could be easily introduced by copolymerizing fluoroalkylacrylates with protonated monomers, such as acrylic acid and methacryloxyethyltrimethyl ammonium chloride [33]. 

Radical-solvent complexes are more difficult to detect spectroscopically however, they do provide a plausible explanation for many of the solvent effects observed in free-radical homopolymerization—particularly those involving unstable radical intermediates (such as vinyl acetate) where complexation can lead to stabilization. For instance, Kamachi (50) observed that the homopropagation rate of vinyl acetate in a variety of aromatic solvents was correlated with the calculated delocalization stabilization energy for complexes between the radical and solvent. If such solvent effects are detected in the homopolymerization of one or both of the comonomers, then they are likely to be present in the copolymerization systems as well. Indeed, radical-complex models have been invoked to explain solvent effects in the copolymerization of vinyl acetate with acrylic acid (51). Radical-solvent complexes are probably not restricted merely to systems with highly unstable propagating radicals. In fact, radical-solvent complexes have even been proposed to explain the effects of some solvents (such as benzyl alcohol, A7 / 7 -dimethyl for-mamide, and acetonitrile) on the homo- and/or copolymerizations of styrene and methyl methacrylate (52-54). Certainly, radical-solvent complexes should be considered in systems where there is a demonstrable solvent effect in the copolymerizations and/or in the respective homopolymerizations. 

The polymerization of 1 can be started thermically, with radicals, or by light [385,390,391]. However, since only oligomers were observed, those homopolymerizations are of academic interest only. 1 has been copolymerized with vinyl chloride and vinyl acetate [392], initiated by redox initiators in emulsion. Copolymers of this monomer are also available by hydrolysis of copolymers containing derivatives of 1-alkenylphosphonic acid, such as dichlorides [392-394] or diesters [395]. Copolymers are also described with acrylonitrile, acrylic amide, N-vinylacetamide, and N-vinylpyrrolidone they are particularly interesting for textile dying, tanning techniques and water separating membranes [396-399]. 

The preparation of copolymers of butadiene and of isoprene with methacrylic acid and with acrylic acid, described by Frank, Kraus, and Haefner in 1952, for use in rubber to metal bonding, was probably the first preparation of carboxylic elastomers made specifically for use as adhesives. They indicated that their consideration of carboxyl groups as a means for enhancing adhesion was stimulated by the observations of Doolittle and Powell " in 1944. They found that low proportions of maleic anhydride (0.1-1%) when copolymerized in copolymers of vinyl chloride with vinyl acetate, improved the adhesion of such films to metal surfaces. McLaren has described an increase in adhesion with increasing carboxyl content of vinylite copolymers to unmodified cellulose. 

To be suitable as a pressure sensitive adhesive, acrylic adhesives are based on acrylic esters with four or more carbon atoms, the most common of which are n-butyl acrylate and 2-ethylhexyl acrylate. These acrylates are copolymerized with other monomers such as acrylonitrile, methyl methacrylate, other acrylates, styrene, vinyl acetate, and a,i8- unsaturated carboxylic acids, depending on the adhesive properties required. This versatility inherent in the acrylics has led to the design of products requiring widely different adhesive properties, from those of permanent labels and high performance tapes to removable labels and films. ... 

The simplest monomer, ethylenesulfonic acid, is made by elimination from sodium hydroxyethyl sulfonate and polyphosphoric acid. Ethylenesulfonic acid is readily polymerized alone or can be incorporated as a copolymer using such monomers as acrylamide, aHyl acrylamide, sodium acrylate, acrylonitrile, methylacrylic acid, and vinyl acetate (222). Styrene and isobutene fail to copolymerize with ethylene sulfonic acid. 

Monomers which can add to their own radicals are capable of copolymerizing with SO2 to give products of variable composition. These include styrene and ring-substituted styrenes (but not a-methylstyrene), vinyl acetate, vinyl bromide, vinyl chloride, and vinyl floride, acrylamide (but not N-substituted acrylamides) and allyl esters. Methyl methacrylate, acrylic acid, acrylates, and acrylonitrile do not copolymerize and in fact can be homopolymer-ized in SO2 as solvent. Dienes such as butadiene and 2-chloro-butadiene do copolymerize, and we will be concerned with the latter cortpound in this discussion. 

During this early period, a very ingenious free-radical route to polyesters was used to introduce weak linkages into the backbones of hydrocarbon polymers and render them susceptible to biodegradabihty (128-131). Copolymerization of ketene acetals with vinyl monomers incorporates an ester linkage into the polymer backbone by rearrangement of the ketene acetal radical as illustrated in equation 13. The ester is a potential site for biological attack. The chemistry has been demonstrated with ethylene (128—131), acrylic acid (132), and styrene (133). 

Hart and de Pauw 98) used this emulsion technique on the system vinyl acetate-acrylic acid. It is well known that the copolymerization parameters rx and r2 are unfavorable in this system therefore the relative solubility of the two monomers exerces only a small influence on the composition of both sequences. The degree of homogeneity of the sequences has been evaluated, after alkaline hydrolysis, by measuring the tendency to lactonization in acid medium. While 72% of the acetate groups could be lactonized in the case of a random copolymer containing 37% vinyl acetate, only 14% are transformed in a block copolymer with the same initial composition. 

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