Acid polymer

Copolymers can be used to introduce a mixture of chemical functionalities into a polymer. Acidic and basic substituents can be introduced, for example, through comonomers like acrylic acid and vinyl pyridine. The resulting copolymers show interesting amphoteric behavior, reversing their charge in solution with changes of pH. 

This may be due to ion—oxide surface interactions or to ions already present on the surface. Alternatively, this deviation may reflect varying sihcate polymer acidity. Similar behavior has been observed for the adsorption of aqueous sihca to the surface of y-Al O (67). Divalent metal ions tend to reduce sihcate adsorption. 

The most common use of curing agents is with carboxylic latices. Isocyanates and melamines can be used but zinc oxide is the most common curing agent. Zinc oxide cross-links carboxylated latices and improves bond strength by ionomer formation [78]. Carboxylated polychloroprene reacts slowly with zinc oxide in dispersed form, causing a gradual increase in adhesive gel content. This can lead to restricted adhesive shelf life. Resin acid sites compete with the polymer acid sites for Zn(II). The more resin acid sites, the more stable the adhesive. 

The strongest known producer of j8-poly(L-malic acid) has been identified as Aureobasidium sp. providing 61 g of polymer from 1 liter of culture medium [5,6]. 8-Poly(L-malate, Ca -salt) of the culture broth was first separated from accompanying bulk pullulan by methanol precipitation. The water-redisolved precipitate was converted to the polymer acid by passage over Amberlite IR-120B (H -form). Thus, the best to-day producers of... 

The purification of j8-poly(L-malic acid) from A o-basiae has been reported involving methanol precipitation of the polymer in the form of the Ca salt [5]. This is possible because a high concentration of CaCOs is present in the growth medium. Unfortunately, the polymer acid is not soluble in aceton thus missing an additional purification step. In our hands, purification of jS-poly(L-malate) from several Aureobasidiae strains was unsatisfactory because of low yields and resisting impurities. 

Extensive data are given in the Uterature for the potentiometric titration of polymer acids which may be used to study the behaviour of polyelectrolyte systems under different conditions. For poly(a-D) galacturonic acid there are few data of this kind, especially in connection with the occurrence of a conformational transition induced by pH variations, or with the effect brought about by the addition or the exchange of counterions. Since for a polyacid not exhibiting a conformational transition in the course of titration, pK K denoting the apparent dissociation constant) increases monotonously with degree... 

Note 2 A polymer bearing acid or basic groups is called a polymer acid or a polymer base, respectively. 

Note 3 A polymer acid or a polymer base can be used as a matrix for ion-conducting polymers. 

Polymer scavengers are used to remove excess reactants and/or by-products from a chemical reaction. For example, nucleophiles are removed by polymer electrophiles and bases are removed with polymer acids. 

Various polymer acids are used as polymer catalysts. Sulfonated polystyrene (Eq. 9-39) has been used to catalyze a variety of acid-catalyzed reactions, including acetal and ketal... 

A full spectrum of licensed petrochemical technologies is featured. These include manufacturing processes for olefins, aromatics, polymers, acids/salts, aldehydes, ketones, nitrogen compounds, chlorides and cyclo-compounds. Over 30 licensing companies have submitted process flow diagrams and informative process descriptions that include economic data, operating conditions, number of commercial installations and more. 

The hydrolysis of esters and amides easily proceeds with the help of mineral adds. Polymer acids are expected to be effident catal3rsts because of the high local density of protons around the pol3mier chain. 

Polymer acids or polyanions can catalyze the acid hydrolyss of esters, amides, and ethers. This is because the local proton concentration in the polymer domain is hi r than that in the bulk phase. The rate acceleration caused by this effect is moderate. However, when substrate molecules are attracted to the polymer molecule by electrostatic and hydrophobic forces, the catalytic efficiency increases (up to ca. 100 fold compared with mineral acids). Similar results were obtained for the alkali hydrolysis in the presence of polycations. 

To minimize the corrosion and scale problems associated with inorganic alkalis such as sodium hydroxide and sodium carbonate, Berger and Lee (2006) proposed an organic alkali. The organic alkali is derived from the sodium salts of certain weak polymer acids. They demonstrated the following benehts by using the organic alkali in the laboratory ... 

Because the data obtained in the case of exposure to hydrochloric acid at 25°C were difficult to interpret and exhibited very slight polymer/acid interaction, the experiments, wherein the polymers were exposed to glacial acetic acid, were run at bO C for seven days in an effort to better define the effects of acids on polystyrene and the SMA copolymers under investigation. 

That concept had led to the synthesis of so-called "halato-telechelic polymers" (which means a "salt" or "neutralized" telechelic polymer, acidic or basic). Although that is a very general denomination covering all the chains formed by any type of ion-pair coupling in any way, a particularly handy and representative class of such structures can be obtained from the complete neutralization of a,o)-dicarboxylato-polymers (PX), by a di (or multi-) valent metal derivative, (19), according to the general equation ... 

When the polymer acids are treated with metallic bases the bulk and solution properties of the neutralized products are changed markedly. In bulk the neutralized products behave as if they are covalently cross-linked. In fact, they are not covalently cross-linked since they are soluble in mixtures of hydrocarbon and polar solvents (12). Nevertheless, their solution behaviors are so significantly different from those of the base polymers and the polymeric sulfonic acids that effective neutralization is not a simple operation. If solutions containing the free polymeric sulfonic acid are treated with an aqueous solution of neutralizing agent, a gel results which prevents effective neutralization and processing. The metal sulfonates are solubilized through the inclusion of a polar cosolvent such... 

There are numerous analytical and characterization steps in resist formulation and lithographic evaluation processes. First of all, each component of a resist formulation, polymer, acid generator, and additives, must be synthesized as... 

Structure Large polymers, acidic Small lipid-soluble molecule... 

This conclusion has been reached in the copolymerization of acrylic acid (AA) and methacrylic acid (MAA) with N-vinylpyrrolidone (34, 35) (a monomer noted for its thermal stability (36) and discussed in Chapter 9) and with acrylamide (37). The incorporation of the acid monomer in the copolymer decreases with increasing solution pH. The r values with MAA are particularly low at pH <5 because of hydrophobic associations of the methyl groups. Laser-Raman studies (38) have also indicated intramolecular association among the methyl groups of syndiotactic poly(methacrylic acid) (PMAA) in aqueous solution. The addition of NaCl, at a moderate pH, increases the amount of neutralized, weak acid monomer incorporated (Table III). A more gradual change is observed with pH in the MAA-AM combination than in the AA-AM pair because of the hydrophobic interactions cited. The relationships are nearly quantitative with the ionization of the acids as reflected by the pK of the monomer and polymer acid sequences. 

Carbohydrates are hydrolyzed by the action of acids. Since polymer acids are efficient catalysts for the hydrolysis of esters and amides, attempts have been made to use them for the hydrdysis of carbohydrates. Kern and co-workers (36) found that tlw catalytic activity of poly(styrenesulfonic acid) 2 in the hydrolysis of sucrose 25 was comparable to that of sulfuric acid. A sulfonated polystyrene gel (cation exchange resin) was sli tly more effective (37). 

Painter and Morgan used poly(styrenesulfonic acid) 2 as catalyst for the selective hydrolysis of polysaccharides (2S). The polymer acid was up to twenty to thirty times more effective than hydrochloric acid in the case of polysaccharides containing free amino groups, but it was 30% less effective for the hydrolysis of unsubstituted starch 26. Obviously, the electrostatic attraction between the polymer and substrate enhanced the catalytic activity. More recently, Tal da reported that amylose sulfate catalyzed the hydrolysis of sucrose 74 times more efficiently than sulfuric acid (39). 

Solid polymer acid electrolytes were first developed for fuel cell applications in the late 1950 s by the General Electric Company (GE), which initiated a program to develop membrane cells and electrolyzers. The first membranes developed by GE for fuel cell applications were made by the condensation of phenolsulfonic acid and formaldehyde. These membranes were found to be brittle, prone to cracking when dried, and rapidly hydrolyzed... 

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