Monomer carboxylic acids

In some cases the polymerization of reactive olefins can be initiated by electrolysis of carboxylic acids. Monomers that have been polymerized this way are styrene [212],... 

A carboxylic acid monomer and an alcohol monomer can join in an ester linkage. 

Fig.4 Traditional and systemic representation of a carboxylic acid monomer...

From a theoretical point of view, any WSP potentially can be suitably modified to construct an associative thickener. Associative ASTs, however, are usually terpolymers consisting of a carboxylic monomer, a hydrophobic monomer, and a third monomer that is associative. These thickeners are prepared by using many of the same polymerization procedures used for conventional ASTs, and many of the same carboxylic acid monomers and hydrophobic monomers are employed. The presence of carboxylic or anhydride monomer is, of course, mandatory, but the hydrophobic monomer can be omitted if the associative monomer is able to impart the proper hydrophilic-hydrophobic balance for the necessary pH-dependent solubility. In Figure 1, the schematic structure of an associative AST is contrasted with that of a conventional AST. Also depicted are other associative moieties, including a nonionic surfactant, an ethoxylated anionic surfactant, and a typical nonionic associative thickener structure. The structural features common to the anionic species and those common to the associative species become obvious. 

Using primarily potentiometric and conductometric titration, several investigators also reported variations in the distribution of the carboxylic acid monomer within the AST emulsion particles. Guziak and Maclay (14) showed that carboxylic acid monomers tended to concentrate near the particle surface of the styrene-acrylic and styrene-butadiene latices studied. Acrylic acid had a greater tendency for surface concentration than did methacrylic acid. Treatment of the latices containing greater than about 20% carboxylic acid monomer with inorganic base produced clear aqueous solutions that were extremely viscous. In an electrophoretic study, Matsumoto and Shimada (16) also found a preferential concentration of acrylic acid near the surface of latices. In contrast, methacrylic acid diffused readily into the particles, where it copolymerized favorably with methyl methacrylate. 

Polymer characterization is an important use of NIR spectrometry. Polymers can be made either from a single monomer, as is polyethylene, or from mixtures of monomers, as are styrene-butadiene rubber from styrene and butadiene and nylon 6-6, made from hexamethylenediamine and adipic acid. An important parameter of such copolymers is the relative amount of each present. This can be determined by NIR for polymers with the appropriate functional groups. Styrene content in a styrene-butadiene copolymer can be measured using the aromatic and aliphatic C—H bands. Nylon can be characterized by the NH band from the amine monomer and the C=0 band from the carboxylic acid monomer. Nitrogen-containing polymers such as nylons, polyurethanes, and urea formaldehyde resins can be measured by using the NH bands. Block copolymers, which are typically made of a soft block of polyester and a hard block containing aromatics, for example, polystyrene, have been analyzed by NIR. These analyses have utilized the... 

Carboxylated polybutadiene ionomers, which are close relatives of the polyethylene ionomers described above, have an essentially polybutadiene backbone that contains some acrylonitrile and styrene to adjust its flexibility and toughness, and, in addition, up to 6% by weight of acrylic or methacrylic acid. Like the polyethylene ionomers, they are usually made by direct copolymerization with the carboxylic acid monomer using, however, emulsion methods. Typically the monomers are slurried in water with sodium dodecylbenzene sulfonate as the emulsifier and potassium persulfate as the free-radical initiator. The tendency of the carboxyhc add monomer to dissolve in the aqueous phase instead of remaining in the butadiene-rich phase is suppressed by making the aqueous phase acidic so that the monomer remains in the nonionized form. 

This chapter concludes with brief reference to carboxylated rubber latexes. Further information, with references, is available in a review by Blackley [27]. Carboxylated rubber latexes contain rubbery polymers which have been modified by inclusion of a small amount of a copolymerisable carboxylic-acid monomer in the emulsion polymerization system by which they were prepared. Typical carboxylic-acid monomers are acrylic acid (XI), methacrylic acid (XII) and itaconic acid (XIII). The most industrially-important rubber latexes of this type are the carboxylated styrene-butadiene rubber latexes. Also of considerable... 

Minor amounts of carboxylic acid monomers are sometimes polymerized into vinyl-acrylic latexes, chiefly for introducing a viscosity response to changes in pH. Acrylic acid (AA) is also used for the pressure-sensitive adhesive market. Gajria and Tjayendran [41] studied the pH response of AA and methaciylic acid (MAA) modified VAc/BA latexes. Feeding the acid in the monomer feed as opposed to a water solution feed produced a greater viscosity response upon pH... 

Two general features of emulsion polymerization reaction systems for the production of carboxylated rubber latexes are of special interest The first b that the polymerization usually takes place under acidic conditions (c. pH 3-4) and not under the alkaline conditions which are usual for the production of non-functionalized synthetic rubber latexes. Polymerization is carried out under acidic conditions in order to encourage the carboxylic acid monomer to become copolymerized into the molecxiles of rubber being prcxluced. If the reaction is carried oui under alkaline conditions, then the carboxylic acid monomer is present mainly as a carboxylate salt which partitions strongly in favour of the aqueous phase If it polymerizes at all under these conditions, polymerization occurs mainly ir the aqueous phase of the reaction system, and the polymer molecxiles in whicl it becomes incorporated are far more hydrophilic than are the majority of the polymer molecxiles, which are produced in the latex particles. The requiremen... 

There is confusion in the literature concerning the nature of the polymers used in glass-ionomers. This stems from the early research of Wilson et al., who studied a range of mono-, di- and tri-carboxylic acid monomers in polymers for cement formation, including itaconic and tricarballic acid [20] and this has led to the assumption that these must be used in practical cements. In fact proprietary materials are all based on the two polymers previously mentioned. 

Similarly, a carboxylic acid monomer and an alcohol monomer can join together to form an ester linkage followed by a loss of water molecule. The monoester thus... 

Although, the lactams are limited to certain geometrically stable ring structures, in theory nearly any combination of an amide and carboxylic acid monomer could create a polyamide. In practice, however, only several major petro-based and bio-based types have been established. 

The bis-carboxylic acid monomers can be polymerized via interfacial techniques from the corresponding acyl halides, while the dibromides can be coupled with R2SiCl2, after ra 5-metallation with alkyl lithium... 

A trifunctional carboxylic acid monomer is being reacted to form a polyanhydride. What is the critical extent of reaction at gelation ... 

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