With chlorophosphazenes properties

The modification of lignins with chlorophosphazenes allows the manufacture of products characterized by flame resistance and thermal stability. This can be attributed to the aromatic structure of the lignin-phosphazene polymer as well as to the presence of such flame inhibiting elements as phosphorous, nitrogen and sulfur. Other useful properties may also result from this combination. It has previously been reported (8-13) that the modification provides crosslinked products with suitably low chlorine content. This is a consequence of incomplete substitution of the phosphazenes cycles. Additional modification of the reaction products by chemical compounds with reactive hydroxyl or amine groups reduces the unreacted chlorine content and improves product properties (8-13). Some properties of the derivatives obtained are presented in Table I. 

In a purely application driven paper, PTFEP, which is known for it excellent membrane forming properties was characterized as a membrane for the removal of thiophene from gasoline. PTFEP in this work was synthesized using the common ring opening polymerization procedure for poly[bis-chlorophosphazene], followed by substitution with sodium 2,2,2-trifluoroethoxide in THF solvent. Solution cast membranes were formed and characterized for transmembrane flux and selectivity using pervaporation as the separation technique. An inverse relationship between selectivity and flux was observed. 

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