Macromolecular salts

Macromolecular salts, using as counterions polyacrylic acids, sulfonic, or phosporylated polysaccharides, have been used to alter drug distribution, for example, by promoting lymphatic uptake of anti-biotics.f ... 

An interesting application of this reaction was the use of macro-molecular anhydrides, namely, styrene-maleic anhydride or vinyl acetate-maleic anhydride copolymers in the presence of perchloric acid as catalyst, these copolymers acylate mesityl oxide or d rpnone to macromolecular pyrylium salts which, with aryl substituents, are fluorescent.No crystalline products could be obtained from succinic anhydride because of the solubility and ease of decarboxylation. 

Block or graft copolymem can be obtained by cationic polymerization of THF with macromolecular initiators. The recommended groups for the initiation are the dioxolenium cation, the acyl cation and the super acid ester, each of which can be introduced into the backbone polymer by reaction with silver salts of strong acids. Introduction of the dioxolenium group into polystyrene was carried out by the following route32 ... 

Then, the macromolecular characterization is necessary to obtain the molecular weight distribution of the polymeric material and the average molecular weights. For this purpose, the first important condition is to get a perfectly molecular soluble material which means to avoid aggregation and/or take off insoluble material. This point was previously discussed [12]. The polysaccharide must be isolated preferentially as a sodium salt form to be fully soluble in water or in presence of some NaCI used to screen electrostatic interactions. 

KM Morimoto, T Nakai, K Morisaka. (1987). Evaluation of permeability enhancement of hydrophilic compounds and macromolecular compounds by bile salts through rabbit corneas in vitro. J Pharm Pharmacol 39 124-126. 

K Morimoto, T Nakamura, K Morisaka. (1989). Effect of medium-chain fatty acid salts on penetration of a hydrophilic compound and a macromolecular compound across rabbit corneas. Arch Int Pharmacodyn 302 18-26. 

As described in previous sections (Sections VI and VII), macromolecular design of polymer/salt hybrids with a highly dissociable lithium borate unit proved to be a valuable approach for single-ion conductive polymers. To further improve the degree of lithium salt dissociation, we have designed a polymer/salt hybrid bearing the boron-stabilized imidoanion (BSI)38 (Fig. 10). 

Finally, mixtures of ionic salts may form glasses, which contain discrete anions (iodide, or molybdate...) without any macromolecular anions. This is the case for glasses in the Agl-AgMoO system for which the pure limiting compositions Agl or AgMoO do not form glasses. 

In comparison with the surface layer chemistry on active cathode materials where both salt anions and solvents are involved, a general perception extracted from various studies is that the salt species has the determining influence on the stabilization of the A1 substrate while the role of solvents does not seem to be pronounced, although individual reports have mentioned that EC/DMC seems to be more corrosive than PC/DEC. Considering the fact that pitting corrosion occurs on A1 in the polymer electrolytes Lilm/PEO or LiTf/PEO, where the reactivity of these macromolecular solvents is negligible at the potentials where the pitting appears, the salt appears to play the dominant role in A1 corrosion. 

In the simplest case, such a system consists of two phases with the same volume. One of them (phase 1) contains KCl in concentration Ci and the potassium salt of a macromolecular anion, KX, in concentration cx The second phase consists only of a KCl solution with concentration c. The system can be depicted by the scheme... 

Amongst the important chemical conversions of macromolecular substances are the various reactions of cellulose. The three hydroxy groups per CRU can be partially or completely esterified or etherified. The number of hydroxy groups acetylated per CRU are indicated by the names, i.e., cellulose triacetate, cellulose 2-acetate, etc. Another commercially important reaction of cellulose is its conversion to dithiocarboxylic acid derivatives (xanthates). Aqueous solutions of the sodium salt are known as viscose they are spun into baths containing mineral acid, thereby regenerating the cellulose in the form of an insoluble fiber known as viscose rayon. 

One of the first methods for making capsules involved polymer coacervation. In this method, macromolecules are dissolved in either the dispersed or continuous phase of an emulsion and are induced to precipitate as a shell around the dispersed phase. Coacervation can be brought about in several ways, such as changes in temperature or pH, addition of salts or a second macromolecular substance, or solvent evaporation (Bungenberg de Jong 1949). 

Poly-3-vinyl-5-hydroxyoxadiazole is a high melting macromolecular compound, which forms metallic salt when dissolved in bases. It might be used as a constituent in antifouling composition, for ion-exchangers, and to increase the dyeability of fibers. 

In accord with experiments on emulsions (Husband et al., 1997), the molecular configurations deduced from SCF calculations have demonstrated the crucial role of the cluster ( blob ) of 5 charged phosphoserine residues in p-casein in maintaining the steric stabilizing layer, whilst also preventing interfacial precipitation (multilayers). The mobility of this blob was demonstrated experimentally by P NMR measurements on P-casein-stabilized emulsions (ter Beek et al., 1996). It was inferred that, when the effective charge on the blob is reduced (by dephosphorylation) or screened (by salt addition), the macromolecular spring relaxes... 

In addition to water and inorganic solids (salts dissolved in cell fluids, shells, and bones), organisms consist of a mix of organic substances. Some of these are macromolecules (e.g., globular proteins, cellulose). Some combine to form subcellular and tissue structures built with combinations of lipids, proteins, carbohydrates, and some specialized polymers like cutin or lignin (Fig. 10.2). These diverse organic materials cause organisms to have diverse macromolecular, cellular, and tissue portions that may be apolar, monopolar, and/or bipolar. 

The fundamental task, in our opinion, is to correlate the principles and methods of the proposed synthesis with those of mechanochemical synthesis. Thus, besides the destruction processes and mechanochemical synthesis discussed in the literature, other lands of transformations sometimes occur as side reactions, or even as major processes. These include chemical fixation of small molecules (methyl chloride or butyl alcohol) on mechanically activated macromolecular backbones grafting of inorganic surfaces (quartz, metals, metallic oxides, inorganic salts, etc.) dispersed by vibratory milling on polymerized fragments synthesized from monomers present in the reaction medium, and activated by centers on the inorganic surface (14) and the possibility of some reactions (such as nitration), achieved so far on macromolecular supports and only as side reactions. 

All authors accept the alternating incorporation of epoxide and anhydride into the macromolecular chain 36 39.40.45 52.73-74). However, the mechanisms of termination and chain transfer have not yet been elucidated. Although the lability of the nitrogen atom is obvious 39 40 44> and its salts or associates are readily thermally decomposed 89), Fischer 39 detected its presence in precipitated polyesters by elemental analysis. A simple calculation confirms the presence of the nitrogen atom in almost every tenth macromolecule. In this case, the isolated polyester might be a living polymer and, on the addition of monomers, it might initiate another copolymerization. Similar experiments have not been reported so far. 

When dissolved in a suitable solvent, uncross-linked poly(dichlorophosphazene) (3.21) functioned as a remarkable macromolecular reactant (reaction sequence (3)). When treated with organic nucleophiles such as the sodium salts of alcohols or phenols, or with primary or secondary amines, all the chlorine atoms along the polymer chain could be replaced by organic units. This is all the more remarkable because an average of 30,000 chlorine atoms per molecule are replaced. 

P. H. von Hippel and K.-Y. Wong, Neutral salts the generality of their effects on the stability of macromolecular conformation, Science 1964, 145, 577-580. 

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