Carboxylic monomer

New efficient vulcanization systems have been introduced in the market based on quaternary ammonium salts initially developed in Italy (29—33) and later adopted in Japan (34) to vulcanize epoxy/carboxyl cure sites. They have been found effective in chlorine containing ACM dual cure site with carboxyl monomer (43). This accelerator system together with a retarder (or scorch inhibitor) based on stearic acid (43) and/or guanidine (29—33) can eliminate post-curing. More recently (47,48), in the United States a proprietary vulcanization package based on zinc diethyldithiocarbamate [14324-55-1]... 

Polymers with a sizable number of ionic groups and a relatively nonpolar backbone are known as ionomers. The term was first used for copolymers of ethylene with carboxylated monomers (such as methacrylic acid) present as salts, and cross-linked thermoreversibly by divalent metal ions. Such polymers are useful as transparent packaging and coating materials. Their fluorinated forms have been made into very interesting ion-exchange membranes (considered further below). 

This terpolymer is formed from methyl acrylate, ethylene and a carboxylic monomer. It has properties comparable to those of an acrylic. Ethylene Dichloride... 

A concept along similar lines was recently developed to account for the auto-accelerated character of the polymerization of carboxylic monomers and of acrylonitrile. Accelerated propagation is assumed to occur in oriented monomer-polymer association complexes. This conclusion is reached on the basis of kinetic evidence and the investigation of molecular associations present in these systems. 

Small amounts of carboxylic monomers (acrylic acid (AA) or methacrylic acid (MAA)) [86] or 2-hydroxyalkyl methacrylates [87] could be easily used in a styrene miniemulsion polymerization, using DMA or SMA as hydrophobe and SDS as emulsifier. 

In the early 1950 s, B.F. Goodrich introduced the first commercial elastomer based on ionic interactions, a poly(butadiene-co-acry-lon1trile-co-acrylic acid). Typically less than 6% of carboxylic monomer 1s employed in order to preserve the elastomeric properties inherent in these systems. When neutralized to the zinc salt, these elastomers display enhanced tensile properties and improved adhesion compared to conventional copolymers. This enhancement of properties can be directly attributed to ionic associations between the metal carboxylate groups. 

Ceska GW. The effect of carboxylic monomers on surfactant-free emulsion copolymerization. J Appl Polym Sci 1974 18 427—437. 

Among the carboxylic acid and anhydride functional monomers that have been employed in the synthesis of these thickener polymers are acrylic acid, methacrylic acid, itaconic acid, citraconic acid, maleic acid, fumaric acid, crotonic acid, maleic anhydride, and citraconic anhydride. The copolymers containing maleic and citraconic anhydride monomers are either hydrolyzed or partially esterified to obtain the required carboxyl functionality. Among these carboxylic monomers, maleic anhydride and particularly methacrylic acid are most frequently favored. Carboxylic homopolymers, where they can be formed, might be considered the simplest examples of ASTs were it not for the fact that they are not copolymers as defined, and some are water soluble in their un-ionized states. Examples of carboxylic homopolymers are the un-ionized free-radical-polymerized atactic forms of polyacrylic acid (i) and polymethacrylic acid (2), which are both readily soluble in water. 

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. 

Terminal Hydrophobe Hydrophobic Linking Group Carboxylic Monomer Or Group Hydrophobic Monomer... 

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... 

The copolymers contain carboxyl monomers and associative monomers only. 

Coordination polymerization of hydroxyl, carboxyl and amino monomers can also be effected by the judicious use of protecting groups. For example, amino and hydroxyl monomers have been protected by silyl ethers and aluminate salts for Ziegler Natta and/or metallocene polynrierization and carboxyl monomers have been protected via aluminate salts. Alternatively, organoborane synthons have been used to carry... 

HgEl l Plausible structure of polymer network based on H-bonded rodlike dimers formed by carboxyl monomer units Incorporated In the polymer side... 

Scheme 4.19 Homopolymerisation of an epoxide-carboxylic monomer. PMA Propylene glycol monomethyl ether acetate TBABr tetrabutylammonium bromide and TPPB tetraphenylphosphonium bromide [78]...

Scheme 6.7 Carboxyl monomers from sunflower oil and castor oil [19, 29]...

Carboxylic monomers, such as acrylic or methacrylic acid, are included in emulsion polymerisation formulations for several reasons to increase the stability of latex particles, to improve the adhesion of resultant films to various substrates, to provide functional groups for interparticle crosslinking reactions and to control the viscosity of latex via neutralisation. Acrylic latices with and without incorporation of carboxylic groups, together with addition of various amounts of anionic surfactant, are used to investigate rheological and drying behaviours of the latices. 9 refs. 

SEMI-BATCH SURFACTANT-FREE EMULSION POLYMERISATION OF BUTYL ACRYLATE IN THE PRESENCE OF CARBOXYLIC MONOMERS... 

A study was made of the impact of incorporation of a small amount of carboxylic monomers (acrylic acid or methacrylic acid) into the latex particles in the limited flocculation process, often encountered in the semi-batch surfactant-free emulsion polymerisation of pure butyl acrylate. The possibility of producing carboxylated polybutyl acrylate latices with a smaller particle size was evaluated. The resultant latex was characterised to gain a better understanding of the effect of the surfactant-free technique on their physical properties, e.g. zeta potential, distribution of acrylic acid or methacrylic acid in the particles, and stability towards the added salt, compared with the conventional emulsion polymerisation system stabiUsed by surfactants. 35 refs. 

Other Anionic Carboxyiate Monomers. The anionic carboxylate monomers 8A and 9A, prepared by the Ritter reaction involving acrylonitrile or methacrylonitrile and 3,3-dimethylacrylic acid have been copolymerized in the sodium salt form to yield calcium-tolerant copoljnners with utility in enhanced oil recovery (145-148). Monomer 8A, for example, has been copol5unerized with 7A... 

Naphthyl groups could be substituted for phenyl groups in all of the structures. And, amine and carboxylate monomers could be mixed to prepare a host of possible copolymers. At least fifteen amines and sixty acids have been condensed to form polybenzimidazoles over the last 25 years [1]. 

An example of a complex seeded polymerization is given in Procedure 4-5. In this process the pH of the seed latex should be maintained between 1 and 3.5, possibly by gradually adding carboxylated monomers or by the use of appropriate acids or bases. The system is interesting since it is a patented method for the production of a vinyl chloride-ethylene copolymer with a 2-thylhexyl acrylate seed polymer and additions of acrylic acid. The procedure is given here for reference only. Not the use of preemulsified monomers in this procedure. 

The OH stretching vibration absorbs sharply and weakly at 3550-3500 cm in CCI4 solution and somewhat higher in the vapor phase. The C=0 stretching vibration absorbs at 1800-1740 cm Table 9.10 lists carboxyl monomer bands. 

Carboxylated rubber latices are commonly produced hy hatch emulsion polymerization. The reaction system comprises the monomers, water, surfactant, initiator, modifier and (usually) inorganic electrolytes. It is essential that polymerization takes place under acid conditions (typically pH ca.4) in order to ensure that the carboxylic acid monomer does become copolymerized in the main polymer molecule which is being produced. If the reaction is carried out under alkaline conditions, then the carboxylating monomer partitions strongly in the aqueous phase as the salt form if it polymerizes at all under these conditions, it is in the aqueous phase that it polymerizes, and the polymer chains in which it becomes incorporated will be far more hydrophilic than the majority of polymer molecules which are produced in the reaction system. In contrast to the production of, say, solid styrene-butadiene rubber by emulsion polymerization, where it is common practice to shortstop the reaction at ca. 65 conversion in order to prevent "undue branching and crosslinking within the polymer, reaction systems for the production of carboxylated latices by emulsion polymerization are usually taken to as near complete conversion as possible. 

As a consequence, entry into the particles is delayed until hydrophobic units are added to promote collapse. And since carboxylic monomer such as acrylic and methacrylic acid, show a strong tendency to react with themselves, the oligomeric species which finally collapse (or are absorbed by other particles) are unusually large and are likely to have a higher concentration of water-soluble segments than is representative of the overall composition of the growing particles. 

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