Polymeric inner salt

Note An ampholytic polymer in which ionic groups of opposite sign are incorporated into the same pendant groups is called, depending on the structure of the pendant groups, a zwitterionic polymer, polymeric inner salt, or poly betaine. 

Eastham et aL ruled out reaction through the inner salt because of the absence of the precipitation and discoloration usually observed with this salt but this argument depends upon concentrations about which little is known. It was observed earlier that the stannic chloride-catalysed polymerization may perhaps proceed through the inner salt so the low yield of dioxane in the present case might result because some of the monomer enters the polymer but the complete absence of deuterium in the dioxane seems to deny this. The problem is an interesting one. 

Zwitterion l-[(4-carboxyphenyl)methyl]tetrahydrothiophenium hydroxide inner salt (557) was polymerized at temperatures ranging from 70° C to 200° C [343]. The copolymer contained oxycarbonyl-l,4-phenyl-enemethylene (A) and oxycarbonyl-l,4-phenylenemethylenethiotetra-methylene (B) repeat units [Eq. (96)]. These units were distributed randomly in the copolymer. 

Figure 74 Initiation of polymerization of the zwitterion l-[4-carboxyphenyl>-methyl] tetrahydrothiophenium hydroxide inner salt. (From Ref. 343.)...

The polymerization of tetrahydro-l-[4-hydroxy-3-(2-hydroxyethoxy)-phenyl]thiophenium hydroxide inner salt was carried out in bulk and in solution. Higher yields (88.3-90.6%) and number-average molecular weights (M = 51,300-67,800) were obtained in bulk. Lower polymer yields (maximum 19%) and lower molecular weights (maximum M = 6930) were obtained in solution. The major products in solution were cyclic oligomers. Increased polymer yields and molecular weights were obtained by the addition of trifluoroacetic acid salts to the solution. 

Figure 75 Polymerization of l-[4-hydroxy-3-(2-hydroxyethoxy)phenyl]thiophe-nium hydroxide inner salt, 563. (From Ref. 344.)...

The complexes of 2,2 -bipyridine and 1,10-phenanthroline have been especially well studied.7 / -Diketones (dike) form stable, inner-salt complexes, Fe(dike)2 these appear to be polymeric with the exception of Fe(Bu COCHCOBu )2. 

Synonyms Siloxanes and silicones, dimethyl-, 3-hydroxypropylmethyl, ethers with polyethylene glycol 3-[dimethyl [3-[(oxotetradecyl) amino] propyl] ammonio]-2-hydroxypropyl hydrogen phosphate, hydroxides, inner salts, chloride Classification Polymeric quaternary ammonium salt... 

The thermal stability of 1-(4-hydroxy-3-methylphenyl)tetra-hydrothlophenlum hydroxide Inner salt (dlhydrate), monomer I Is much lower than l-(3,5-dlchloro-4-hydroxyphenyl)tetrahydrothlo-phenlum hydroxide Inner salt, monomer II. Differential thermal analysis of I Indicates polymerization begins at 75°C,but monomer II does not begin polymerization until 150 C (9). 

In addition to these inner salts, a number of monomeric salt pairs have been prepared [93]. In these systems a vinyl acid such as vinyl sulfonic acid was reacted with a vinyl base such as vinyl pyridine in THF. The precipitated salt was washed and purified. Polymerization of the salt was accomplished in the aqueous solution with a thermal initiator. Other salt pairs include acrylate and acrylamide derivatives with sulfonic groups as the anionic constituents and tertiary or quaternary amino pendant groups as the cationic constituents [94]. 

Direct polymerization from sulfonated monomers is the most widely used method for the synthesis of the SPIs. The synthesis is usually performed by polycondensation reaction of sulfonated diamine monomers with tetracarboxylic dianhydride monomers in m-cresol in the presence of triethyl amine (EtjN) and benzoic acid at around 180°C [4,7,10,11,13,28-34]. Sulfonated diamines are inner salts that are formed due to the interaction of the sulfonic add groups and the basic amino groups, and the function of the EtsN is to liberate the protonated amino groups of sulfonated diamines for polymerization with the 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTDA),... 

Polymerizations. The polymerizations were carried out in an argon atmosphere in capped glass bottles fitted with a neoprene rubber gasket inner liner. In charging the polymerizations, the order of addition of materials was solvent first, then metal alkyls, next the barium salt, and finally the monomer(s). The amount of metal alkyl charged was sufficient to titrate the acidic impurities present in the solvent and polymerization bottle, plus the calculated amount for initiation of polymerizations. The mole ratio of barium to metal alkyl(s) was based on the moles of total alkalinity of barium to the moles of carbon-metal assayed. Unless otherwise stated,... 

The conversion rates, and the selectivities of the various catalysts used, are listed in Table 7.2. Among these, CuCl was seen to be the most efficient, but no carbonate was produced however, the substrate was very effectively converted when noble metal salts such as Pd(II), Rh(III), Ru(III), and Au(III) were used as catalysts. This behavior may be explained only if a polymerization reaction were to occur when the noble metal salts/[BMIm][PhS03] systems had been used, as confirmed by the presence of some black tar on the inner wall of the reactor when the reaction had been completed. In the absence of a metal salt as catalyst, the reaction did not yield any product, even after a long reaction time. 

Most RE have the components shown in Fig. 4. In order to maintain the RE at equilibrium, a glass or polymeric body separates the inner, or fill, solution from the test environment. The ionic communication with the test solution needed is controlled, often through a porous frit. The electrode interface itself is often composed of a metal coated with a metal salt. This arrangement often leads to a robust equilibrium condition as long as some metal salt is present on the electrode surface, the potential of the RE is independent of the amount of salt. The composition of the All solution is important in maintaining the RE at equilibrium. 

In summary, the arthropod cuticle is not chitinous and can probably best be described as a plasticized, protein sheet, variously subdivided to give a laminar structure by (a) the addition of waxes at the outer surfaces and chitin in the inner parts, and (b) hardening due to impregnation with calcium salts or further polymerization with polyphenols, or both. 

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