Dispersions polysaccharide-metal

Macromolecular conformations and reversible order-disorder and disorder-order transitions are highly sensitive to solvent, temperature, pressure, pH, water activity, and metal ions. Polyanions are distinguished from neutral molecules by their sensitivity to electrolytes. Whereas synthetic polymers do not normally dissolve or disperse spontaneously, some polysaccharides may do so in water (hydration), given their strong hydrophilicity. 

Degradation of the polysaccharide during methylation can be minimized by performing the reaction at low temperatures and in an atmosphere of nitrogen. Methylation is facilitated by simultaneous deacetylation and methylation of the polysaccharide acetate dispersed in an inert solvent IJiS), Fully methylated polysaccharides are obtained only after repeated methylations, which are often completed by a final methylation with a mixture of silver oxide and methyl iodide. Resistant hydroxyl groups may be methylated by the alternate addition of sodium metal and methyl iodide to the polysaccharide dispersed in liquid ammonia... 

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