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2-Ethylhexylpoly(trimethylene 1,3-phosphate) (3). poly(l,2-glycerol phosphate) (1) and poly-(l-acetoxy-2,3-glycerol phosphate) (2) were synthesized and used as synthetic analogues of teichoic acids. Their properties as a carrier of magnesium and calcium ions were examined in the competitive exchange diffusion process with the countertransport of hydrogen or sodium ions. It turned out that polymers with 1,2-glycerol phosphate units (1,2) exhibit lower ability to transport preferentially magnesium ions than poly(l,3-alkylene phosphate+ (3). In all cases the efficiency of polyphosphates in preferential transport of magnesium ions is higher when transport is coupled with proton counterflow. 0 1990, Hitthig & Wepf Verlag, Basel CCC 0025-1 16X/90/$03.00

synopsisThis article deals with the method of determination of a threshold volume fraction of the conductive phase within perfluorosulfonic acid ionomer Nafion. Experiments have been performed with the commercial Nafion-120 and Nafion-427 membranes equilibrated with concentrated sodium chloride and sodium hydroxide solutions at 353 K. It has been stated that the insulator-to-conductor transition in membranes occurs at the critical volume fraction of the conductive phase (VJ equal to 0.1. The same V, has been estimated for a geometrical cluster-network model. Lower than the theoretical V, for a classical dense-packed-hard-sphere model (V, = 0.15), the volume fraction for the membranes is caused mainly by channels connecting the ionic clusters. The critical exponent t has been calculated for both membranes and found to be equal to 1.6 for Nafion-120 and 1.5 for Nafion-427. Both these constants correspond to those theoretically predicted for 3D systems. The ratios of sodium ion mobility in the internal membrane solution to its mobility in the equilibrating NaCl or NaOH solutions (U + / u +) are below unity, and they are dependent on the nature and concentration of the electrolyte.

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Experimental investigations are presented on the application of poly-[poly(ethylene glycol) phosphate] (PEGP) as a macromolecular, multisite, carrier of ions in an emulsion liquid membrane system. This polymer acts as a mobile carrier and surfactant-stabilizing WIOI W emulsion. The transport properties of PEGP have been checked for systems composed of (a) a feed phase containing Ni(II), Co(I1) or Cu(I1) ions; (b) an organic phase, i.e., PEGP dissolved in 1.2-dichloroethane; and (c) 1 M sulfuric acid as a receiving solution. Fast and effective membrane extraction of Ni(I1) has been found for membranes with PEGP of molecular weight 22,000. It has been proved that the affinity of PEGP toward the studied ions is reversed in comparison with that for poly(ethy1ene glycol). The affinity order of PEGP toward the tested ions is Ni(I1) > Co(I1) > Cu(I1).