Poly pair

Association Complexes. The unshared electron pairs of the ether oxygens, which give the polymer strong hydrogen bonding affinity, can also take part in association reactions with a variety of monomeric and polymeric electron acceptors (40,41). These include poly(acryhc acid), poly(methacryhc acid), copolymers of maleic and acryflc acids, tannic acid, naphthoHc and phenoHc compounds, as well as urea and thiourea (42—47). 

Tubular film may be biaxially oriented by passing eooled film through a pair of nip rolls, reheating it to a uniform temperature and then passing it between a further pair of rolls. Between the two pairs of rolls a mandrel of air is introduced in order to expand the film. The proeess is similar to that shown for poly(vinylidene ehloride) in Figure 17.4. 

Pyridinium ylide is considered to be the adduct car-bene to the lone pair of nitrogen in pyridine. The validity of this assumption was confirmed by Tozume et al. [12J. They obtained pyridinium bis-(methoxycarbonyl) meth-ylide by the photolysis of dimethyl diazomalonate in pyridine. Matsuyama et al. [13] reported that the pyridinium ylide was produced quantitatively by the transylidalion of sulfonium ylide with pyridine in the presence of some sulfides. However, in their method it was not easy to separate the end products. Kondo and his coworkers [14] noticed that this disadvantage was overcome by the use of carbon disulfide as a catalyst. Therefore, they used this reaction to prepare poly[4-vinylpyridinium bis-(methoxycarbonyl) methylide (Scheme 12) by stirring a solution of poly(4-vinylpyridine), methylphenylsulfo-nium bis-(methoxycarbonyl)methylide, and carbon disulfide in chloroform for 2 days at room temperature. 

Cationic polymerization of tetrahydrofuran with the or bis(3,5-di-bromomethyl) benzoyl peroxide and AgPp6 pairs of 4,4 -bromomethyl benzoyl peroxide and AgPp6 yield active poly-THP having peroxide group in the main... 

Finally, ion chromatography can be used to determine the a-sulfo fatty acid esters. The chromatographic column is a nonpolar poly sty rene/divinylbenzene column and the ion pair reagent is 0.005 M ammonia. In order to reduce the elution time, acetonitrile is added as a modifier with increasing concentration. This gradient technique makes it possible to separate simultaneously ester sulfonates and disalts by chain length. Determination is achieved by standards with defined chain length [107]. 

The second strategy is to replace the vinylene bridges of PPV (B) by a heteroatom possessing a lone pair that can participate in the n-conjugation [4]. Representative examples of this class of derivative (D) (Fig. 1) are the polyanilines and poly(p-phenylenesulfide) [la,b]. 

Polyphosphazenes sulfonates XIX with the anion covalently attached to the polymer are a new class of cation conductors that have been synthesized by Shriver [625]. They were obtained by reaction of Na0C2H4S03Na with an excess of polydichlorophosphazene in the presence of 15-crown-5, followed by the reaction of the partially substituted product with the sodium salt of poly(ethylene glycol methyl ether). The conductivity at 80 °C of the polymer with x=1.8, m=7.22 is 1.7x10 S cm This low conductivity can be attributed to an extensive ion pair formation between the sodium and sulfonate ions. 

FIG. 9 Schematic illustration of adsorption of poly(styrenesulfonate) on an oppositely charged surface. For an amphiphile surface in pure water or in simple electrolyte solutions, dissociation of charged groups leads to buildup of a classical double layer, (a) In the initial stage of adsorption, the polymer forms stoichiometric ion pairs and the layer becomes electroneutral, (b) At higher polyion concentrations, a process of restructuring of the adsorbed polymer builds a new double layer by additional binding of the polymer. 

Countless macrocycles containing basic functionalities have been synthesized and, for a large number of compounds, values have been determined (Patai, 1980 Gokel and Korzenowski, 1982 Kaden, 1984 Kimura, 1985 Lindoy, 1989 Vogtle, 1989, 1991 Gokel, 1991, 1992 Izatt et al., 1991, 1992 Dietrich et al., 1993). Usually, the basic function in these macrocycles is a nitrogen atom the compounds are (poly)azamacrocycles. But in azacrowns like [1] or cyclams [2] the /n-orientation of the lone pair at the nitrogen atom is not assured. Murakami et al. (1991) synthesized the... 

In the previous Sections, the properties of acids and bases in macrocycles and other concave structures have been compared. A number of factors have been recognized which influence the acidity or basicity of an acid or base (i) hydrogen bonds, (ii) hindered solvation (exclusion of solvent), (iii) formation of tight ion pairs (high microacidity but low overall acidity), and (iv) Coulomb forces when poly anions are formed. A fifth influence, (v) steric hindrance, still has to be discussed. 

Fig. 39.—Plots of c/c against c from the data of Masson and Melville for the following solvent-polymer pairs curve 1, polyacrylonitrile in dimethylformamide at 13.5° C curves 2 and 4, poly-(vinyl acetate) s in benzene at 20°C curve 3, polyacenaphthylene in benzene at 25°C curve 5, polyvinylxylene in benzene at 24°C curve 6, poly-(methyl methacrylate) in benzene at 16°C. All curves have been calculated from Eq. (13). Units correspond to those in Fig. 38. (Fox, Flory, and Bueche. )...

These were prepared by efficiently interhnking pairs of carboxyl end groups in fibers extruded from tetra-chain and from octachain poly- -caproamides (see p. 

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