Monomer carboxyl-containing

Cure-Site Monomers. A large variety of cure-site monomers has been proposed, but only a few have achieved commercial significance. Two of the most important classes are labile chlorine containing monomers and epoxy/carboxyl containing monomers. 

Bassett and Hoy (7,8) investigated the influence of the method of monomer addition on the alkali-swelling behavior. In this case, carboxyl-containing monomers were fed in three different stages of the semi-continuous polymerization (i) in the... 

Numerous water-soluble monomers have been polymerized via ATRP (Fig. 7.3). Polymerization of acrylic and methacrylic monomers can be problematic as these monomers often contain trace impurities of acryhc or methacrylic acid (MAA). The presence of these carboxylic containing monomers can be detrimental for example, Matyjaszewski et al. have observed that (non-aqueous) polymerization of acrylic acid cannot be controlled with ](bpy)2CuCl] (bpy=2,2 -bipyridine), as the monomer (and the polymer) is likely to coordinate to the metal center, to form a species that is unable to control the polymerization [198]. 

In the nonaqueous polymerization processes that are conducted in organic solvent or diluent, many of the carboxyl-containing monomers cited have successfully been used in the preparation of ASNE and HASNE ASTs. Reactivity ratios, rates of reaction, monomer-polymer solubilities, economics, and degree of polymerization were among the criteria considered in monomer selection. However, in the important aqueous processes of suspension and particularly emulsion polymerization, the water solubility and hydrophilicity of the carboxylic monomer was found to be of considerable importance. Fordyce and Ham (13) observed that a significant portion of itaconic acid polymerized in the aqueous phase when emulsion polymerization was carried out with styrene. Fordyce et al. (9, 10) reported that... 

Non-covalent Interactions. Hosbach et al. (73) prepared L-phenylalanine-ethylester-selective polymers using the ion-pair association of template and carboxyl containing monomers in the polymerization step. The selectivity for racemic resolution with a - 1.04 - 1.08 was not very marked, but these polymers can easily be prepared. 

Another approach was used by Mosbach et al. (77,78). They performed crosslinking copolymerization in the presence of certain dyes and added some carboxyl-containing monomers. The prepared polymers showed a marked selectivity for the template that was used in the preparation of the polymer. 

A new class of metal-loaded nanoparticles was developed by Reynolds et al. (95). These materials have a core-shell morphology, where the core is a functionalized polymer with a high affinity to the Gd(III) ions. The core polymer contained monomers with carboxylate pendant arms, such as ethylacrylate, methacrylate, butylacrylate or allylmethacrylate. The shell consisted of a... 

B. J. Synthetic hydrogels 2. Copolymers of carboxyl-, lactam- and amide-containing monomers—Structure/ property relationships. Polymer 1988, 29, 691-700. 

An alternative approach involves the polymerization of a suitable tin-containing monomer, 4 and was recently employed by Angiolini and coworkers,33 with the preparation of grafted organotin carboxylates by copolymerization of triorganotin derivatives of p-vinylbenzoic acid (p-VBA) with styrene and 1,4-divinylbenzene. 

Ionomers of practical interest have been prepared by two synthetic routes (a) copolymerization of a low level of functionalized monomer with an olefinically unsaturated monomer or (b) direct functionalization of a preformed polymer. Typically, carboxyl containing ionomers are obtained by direct copolymerization of acrylic or methacrylic acid with ethylene, styrene and similar comonomers by free radical copoly-merization. Rees (22) has described the preparation of a number of such copolymers. The resulting copolymer is generally available as the free acid which can be neutralized to the degree desired with metal hydroxides, acetates and similar salts. Recently, Weiss et al.(23-26) have described the preparation of sulfonated ionomers by copolymerization of sodium styrene sulfonate with butadiene or styrene. 

RAFT is effective with a wide range of monomers, but distinguishes itself from SFRP and ATRP in that it can polymerize carboxylic acid-containing monomers such as methacrylic acid [46]. The polymerizations are performed at temperatures of 100 °C or less with typical polydispersities in the 1.1 1.25 range under either bulk, solution or emulsion conditions. Initially formed homopolymers can readily be chain extended or transformed into block copolymers by reaction with a second monomer [47]. 

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... 

Ill) Epoxy functionalities are not essential for grafting. For a graft copolymer made by the reaction of epoxy with carboxyl functionalities, the presence of epoxy functionalities is essential. Since this approach requires carbon-carbon bond formation, ester linkages are not necessary. Therefore epoxy functionalities can be capped with phenol or benzoic acid, etc., or bisphenol-A terminated epoxy resin can be prepared followed by grafting with acid containing monomers, and resultant epoxy-g-acrylic copolymer can be prepared. 

The surfactants usually used in the emulsion polymerizations of nonfluorine-containing monomers appear to be unsatisfactory in the case of vinyl fluoride polymerizations [6]. Salts of the higher perfluorinated carboxylic acids are more suitable emulsifiers. Cationic surfactants based on perfluoroalkylpropylamines are used in a recent patent for the emulsion polymerization of vinyl fluoride [36]. 

The preparation of ionomers involves either the copolymerization of a functionalized monomer with an olefinic unsaturated monomer or direct functionalization of a preformed polymer. Typically, free-radical copolymerization of ethylene, styrene, or other a-olefins with acrylic acid or methacrylic acid results in carboxyl-containing ionomers. The copolymer, available as a free acid, is then neutralized partially to a desired degree with metal hydroxides, acetates, or similar salts. The second route for the preparation of ionomers involves modification of a preformed polymer. For example, sulfonated polystyrene is obtained by direct sulfonation of polystyrene in a homogeneous solution followed by neutralization of the acid to the desired level. Some commercially available ionomers are listed in Table 15.17. 

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. 

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