Polymers, ionic solution properties

The effects of calcium on polymer-solvent and polymer-surface interactions are dependent on polymer ionicity a maximum intrinsic viscosity and a minimum adsorption density as a function of polymer ionicity are obtained. For xanthan, on the other hand, no influence of specific polymer-calcium interaction is detected either on solution or on adsorption properties, and the increase in adsorption due to calcium addition is mainly due to reduction in electrostatic repulsion. The maximum adsorption density of xanthan is also found to be independent of the nature of the adsorbent surface, and the value is close to that calculated for a closely-packed monolayer of aligned molecules. 

Effect of Polymer Ionicity. The influence of polymer ionicity on solution and adsorption properties is investigated for polyacrylamides varying from 0-50% ionicity in the absence and presence of calcium. 

In the mucosal environment, effects of salt, pH, temperature, and lipids need to be taken into consideration for possible effects on viscosity and solubility. A pH range of 4-7 and a relatively constant temperature of 37°C can generally be expected. Observed solution properties as a function of salt and polymer concentration can be referred to as saline compatibility. Polyelectrolyte solution behavior [27] is generally dominated by ionic interactions, such as with other materials of like charge (repulsive), opposite charge (attractive), solvent ionic character (dielectric), and dissolved ions (i.e., salt). In general, at a constant polymer concentration, an increase in the salt concentration decreases the viscosity, due to decreasing the hydrodynamic volume of the polymer at a critical salt concentration precipitation may occur. 

Molecular weight characterization of modacrylic fibers is difficult because of the limited number of solvents available and inhomogeneties in composition between individual polymer chains that affect solution properties, particularly if the comonomers are ionic in character. Di-methylformamide and dimethylacetamide are suitable for measurement of molecular weight of polyacrylonitrile, but errors are introduced when copolymers are analyzed (126). Bortniak et al. (127) have analyzed modacrylic fibers quantitatively in microgram quantities by using pyrolysis gas chromatography. 

Although there is no strict boundary line, we have divided polymers into water soluble polymers and water-insoluble systems, typified respectively by materials used to prepare viscous solutions and those which function as barrier membranes or containers, in the first case we have considered the factors controlling their properties the influence of molecular weight (distribution), branching, charge, flexibility, ionic strength and pH on solution properties, in the case of water-soluble polymers, the main concern has been with... 

Many ionomers are used in polymer blends as a compatibilizer, because the ionomers have at least two different properties, that is, hydrophobic host-polymer matrix and hydrophilic ionic groups and/or aggregates. In addition, the solution properties of mixtures including the ionomers have also been investigated to clarify the details of characteristics not only in blending but also in micellar structures. For example, Bosse and Eisenberg recently reported on the kinetics of coil overlap in ionomer blends in DMSO by means of H NMR.47,48... 

H-S. Xu and C-Z. Yang, The ionic conductive properties of sulfonated polyethylene oxide polyurethane, J. Polym. Sci., Polym. Phys. Ed., 1995, 33, 745-751 G. Robila, T. Buruiana and E.C. Buruiana, Sulfonated polyurethane ionomers in solution, Angew. Makromol. Chem., 1995, 231, 25-33, etc. 

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