Phosphorylated polysaccharides. 2. Synthesis and properties of phosphorylated dextran

New results regarding the synthesis and characterization of water-soluble phosphorylated dextran (PDex) are presented. The phosphorylation was made by reaction of dextran with phosphorous acid in molten urea. The structure of phosphorylated product was investigated by elemental analysis, by titration of acidic groups and by FTIR and NMR spectroscopy. It was found that phosphorylated dextran prepared in these conditions is a monobasic dextran phosphate with (H)P(O)(OH) groups. The degree of polymerization of PDex was found comparable to the parent dextran, suggesting that polysaccharide chain was not degraded during phosphorylation. The polyelectrolyte behavior was studied by potentiometric and conductometric titration and by viscometric measurements.