Phosphazene uses

Other synthetic routes to phosphazenes, using phosphorus(v) compounds as substrates, are more limited. An example of the reaction of a nitrile with a phos-phorus(v) chloride is provided by Scheme 4.48 In benzene solution, or in the absence... 

Structures of Some Example Poly(phosphazenes) Used in Drug Delivery... 

Magill JJ, Riekel C (1986) A phase transition study in poly[l s(p-methylphenoxy)phosphazene] using synchrotron radiation. Makromol. Chemie, Rapid Comm. 7 287... 

On the other hand, Wisian-Neilson and Neilson [46-48] report a condensation method that leads to the formation of polyphosphazenes. In this route, NH-(Si-(CH3)3)2 is reacted in the presence of n-butyllithium and PCI3 to form the dichloride phosphazene using the Grignard reactant, as depicted in Figure 3.16... 

Polyl(trifluoroethoxy)(octafiuoro pentoxy)]phosphazene decomposes thermally by random chain scission. The decomposition process has been studied in detail for polyKbis trifluoroethoxy) phosphazene] using n.m.r., i.r. spectroscopy, gas chromotography, mass spectrometry, and electron spectroscopy for chemical analysis. Random chain scission is confirmed followed by depolymerization with an average zip length of 35 chain units. The thermo-oxidation of a hydroquinone-phosphorus oxychloride copolymer has also been investigated. Decomposition is a two-stage process, chain scission to form quinone followed by oxidation of the quinone to maleic anhydride. ... 

Fig. 18 Direct methanol fuel-cell performance curves with membranes composed of PBI-doped sulfonated poly[bis(phenoxy)phosphazene] using a sandwich MEA design, and b direct hotpressing of electrodes. 1.0 M methanol feed, 60 °C, ambient pressure air at 500 seem. Cross denotes the methanol crossover flux (mol/cm min) at open circuit, relative to that in Nafion 117...

Another example was a simple two component blending experiment between a phosphazene polymer and a carboxylic acid functionalized MWCNT.The phosphazene used in this example was a heteropolymer... 

The studies on separation of water isotopomers (HTO, HDO, H2O) with membranes from poly[bis(phenoxy)phosphazene] and carboxylated derivatives were carried on in Pacific Northwest Laboratory [112,113]. Using these membranes tritiated water was extracted from fuel storing pool water of 3 pCi/L concentration of tritium, and from facilities under supervision of US DOE in Hanford and Savannah River. Separation with 10,800 pCi/L tritiated water obtained by membrane method was not higher than 33% (depletion in the permeate fraction). Water containing 3 pCi/L of HTO was depleted by 22% in a similar system [113]. 

From Figure 13, it is seen that a phosphazene trimer (PNCl2)3 has an S3 axis of symmetry. The C3 axis of rotation is perpendicular to the equilateral triangle obtained by joining three phosphorous atoms. The two chlorine atoms bound to each phosphorous atoms are above and below the plane of the triangle. A rotation of 120° followed by reflection in the plane perpendicular to this axis retains the appearance of the molecule with the new positions of the chlorine atoms. A few more operations on the above mentioned molecule can also lead us to derive the following relations. 

This electrolyte displays high room temperature conductivity which in most cases is 2-3 orders of magnitude greater than similar PEG complexes. The success of the phosphazene-based electrolyte led us to consider other polymer electrolytes with inorganic backbones. 

Since the middle of sixties, when H.R.Allcock first reported the synthesis of poly(organophosphazenes), (POPs) (1-3), the scientific, technological and industrial relevance of these materials has increased tremendously (4-7). During the last decade our interest in this field was mainly focused on the photochemistry and photophysics of POPs, and on their possible practical exploitation in the photochemical field (8,9). A few years ago, however, we became interested also in the functionalization of POPs as obtained by the introduction of suitable chemical functionalities in selected macromolecules. These investigations led us to the synthesis and characterization of water-soluble phosphazenes (10-14), double-bond-containing substrates (15,16), and polymers bearing epoxide moieties (16). 

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