Polymer salt interactions

It is worth recalling that polymer-salt interactions in systems other than the polyethers also have been explored, primarily in highly crystalline materials. However, they will not be reviewed here because of the dissimilarity of those polymers and the preliminary nature of this report. It should also be mentioned that the effect of salts in increasing the viscosity of the polyethers has been described in the commercial literature on these materials, but the information is of a qualitative nature only. 

Wissbrum and Hannon have used variations in Tg to investigate polymer-salt interactions in a number of polymers (180). One of their studies involved complexation of a copolymer prepared from 2,2-bis-4-hydroxyphenylpropane and epichlorohydrin with calcium thiocyanate (181). The salt caused an increase in Tg that was related to reduction in the free volume of the polymer. 

The glass transition temperatures of these polymers also increased with salt content, because of a stiffening of the structure, which can be ascribed to the formation of transient crosslinks between solvating moieties through the metal ions. The increase in viscosity of liquid poly(propylene glycol) on salt addition was, in fact, one of the first experimental observations symptomatic of a polymer-salt interaction. ... 

In all cases of high conductivity, the polymer-salt interaction causes an increase in Tg (which is, in this case, proportional to the square root of concentration), e.g. Figure 5(c), and therefore a decrease in mobility according to the VTF expression. This explains why the addition of salt causes an approximately linear increase in conductivity at very low concentration (where the increase in carrier concentration is dominant) followed by a decrease at high concentration due to the decrease... 

We are now in possession of the following information (1) the previously detected complex between and PEO in CD3OD has a pronounced effect on (2) a looser polymer-salt interaction, such as that responsible for salting out , in K2SO4-PEO-D2O solutions, has no apparent effect on (3) the salting-out interaction has a pronounced effect on solution viscosity. Complex formation may also affect polymer viscosity but it is difficult to separate its influence from the salting-out process. 

Diazo Coupling Reactions. Alkylphenols undergo a coupling reaction with dia2onium salts which is the basis for the preparation of a class of uv light stabilizers for polymers. The interaction of orxv i -nitrobenzenediazonium chloride with 2,4-di-/ r2 -butylphenol results in an azo-coupled product (30). Reduction of the nitro group followed by m situ cyclization affords the benzottiazole (31) (19). 

Of the preponderance of small ions, the colligative properties of polyelectrolytes in ionising solvents measure counterion activities rather than Molecular weight. In the presence of added salt, however, correct Molecular weights of polyelectrolytes can be measured by membrane osmometry, since the small ions can move across the membrane. The second virial coefficient differs from that previously defined, since it is determined by both ionic and non-ionic polymer-solvent interactions. 

The interaction of poly(ethylene oxide) and other polar polymers with metal salts has been known for many years (Bailey and Koleska, 1976). Fenton, Parker and Wright (1973) reported that alkali metal salts form crystalline complexes with poly(ethylene oxide) and a few years later, Wright (1975) reported that these materials exhibit significant ionic conductivity. Armand, Chabagno and Duclot (1978, 1979) recognised the potential of these materials in electro-chemical devices and this prompted them to perform more detailed electrical characterisation. These reports kindled research on the fundamentals of ion transport in polymers and detailed studies of the applications of polymer-salt complexes in a wide variety of devices. 

Polymer/solvent interactions may also be affected by ions. Salting in/salting out phenomena [20], as well as the alteration of gel water structure due to ionization of pendant groups [29], will affect the polymer/solvent interaction component of Ilnet. 

Other important methods of synthesis of coordination compounds are discussed in detail [1,3,10,11,53,201,202,206,207,316,318,322,690]. In this respect, we emphasize the synthesis of metal-polymers [690,691] and preparation of complexes in the solid phase (mechano- or tribosynthesis) [10,201,202,206]. Additionally to the above-described techniques, the general methods and principles of synthesis of coordination compounds are used to obtain metal-polymers (immediate interaction of polymer ligands and metal salts, template electrosynthesis, polymer-analogous transformations). The last method consists of the polymerization of metal-monomers (metal-containing monomers) and fixation of metal complexes on the polymer... 

Wyzgoski MG, Novak GE (1987) Stress cracking of nylon polymers in aqueous salt solutions - Part II. Nylon-salt interactions. J Mater Sci 22(5) 1715-1723... 

Some papers60-61 have been devoted to phase separation of polyionic complexes from partially furated (PVA-S) and aminoacetylated (PVA-AAC)poly(vinyl alcohol) in aqueous salt solutions. The separation liquid-liquid or complex coacervation occurs at a definite value of the charge density on the macromolecule. From the concentration dependence of the reduced viscosity of the initial components PVA-S, PVA-AAc and their equivalent mixture in water it follows that the viscosity of the components noticeably increases with dilution, and the curve of the equivalent mixture is concentration independent. This fact confirms the formation of the neutral polymer salt, due to electrostatic interactions of PVA-S (strong polyadd) and PVA-AAc (weak polybase). 

Polymers Interact with surfactants and mlcroemulslons In diverse. Interesting and technologically Important wavs(1.21. The mechanisms that are responsible for the Interactions Include the usual panoply of forces Involved In the interaction of any two different molecules lon-lon, lon-dlpole, dlpole-dlpole, and van der Waals forces all modulated by the presence of solvent and/ or other species such as dissolved salts. All may play a role. The special factors Involved in surfactant/polymer and polymer-/mlcroemulslon Interactions that form the basis for their particular interest lies in their tendencies to form a variety of supermolecular clusters and conformations, which In tuim may lead to the existence of separate phases of coexisting species. Micelles may form In association with the polymer, polymer may precipitate or be solubilized, mlcroemulslon phase boundaries may change, and so on. 

Based on these observations, the distinction between water penetration and salt intrusion may be schematically represented as shown in Figures 24.14 and 24.15. In these figures, two interfaces— film/water and film/metal—are involved, and the effect of lack of water-insensitive adhesion at the film/metal interface is also depicted. In the absence of water-insensitive adhesion, water molecules that reach the polymer/ metal interface cluster together by breaking weak polymer metal interaction. If one... 

Besides degree of substitution, nature of substituents, solvent, concentration, and temperature, other factors that change the polymer-solvent interactions can affect the pitch of lyotropic cellulosic mesophases. Doping inorganic salts " or small chiral molecules into the lyotropic mesophase changes the polymer-solvent interactions. As the results, the pitch of the chiral nematic mesophase changes accordingly. 

The main drawback to the widespread use of polymer-polymer aqueous two-phase extraction has been the high cost of fractionated dextran. Crude dextran has been used with some success for the purification of enzymes but is much too viscous for many applications. Conversely, polymer-salt systems have relatively low viscosities, separate rapidly, and are inexpensive. Unfortunately, they lack selectivity and cannot be used for affinity partitioning in most cases since the high salt concentrations interfere with the protein-ligand interaction. The starch derivatives are reasonable alternatives for bottom phase polymers but have been hampered by low solubilities and the tendency for gel formation. Tjemeld has reported that chemically modified starches i.e. hydroxypropyl starch... 

The more polymer chains interact with the solvent, the less they will interact with each other and, for neutral polysaccharides in water or anionic polysaccharides in salt solutions, lies between 0.3 and 05. ... 

Numerous workers50 51 52 53 have studied the effect of the counterion on the electropolymerization process. The high concentration of counterion employed means that it can have a dramatic effect on the polymerization process. The electrolyte will influence the conductivity of the solution, the polymer properties and, hence, the rate of polymerization. The nature of the electrolyte salt employed can also have a marked effect on polymer-solvent interactions. 

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