| Popis: |
Glycol chitosan (GC) and methyl glycol chitosan (MGC) were, individually, reacted with potassium metaphosphate (MPK) to form a series of water-insoluble macromolecular complexes (MC) in aqueous solution at different hydrogen ion concentrations (GC-MPK and MGC-MPK systems). GC was reacted with MPK in the presence of CaCl2 (GC-MPK-CaCl2 system) as well as in the absence of CaCl2. The properties of MC obtained were studied. On the basis of elemental analysis, solubilities, and thermogravimetry analysis, it is suggested that the molecular structure of each MC depends on the hydrogen ion concentration and whether Ca2+ ion is present or not. MC prepared at pH 1,0 are composed of a relatively loose network including a small quantity of MPK, whereas those MC prepared at neutral and higher pH are composed of a relatively tight network including a large quantity of MPK. As compared with MC in the GC-MPK system, those in the GC-MPK-CaCl2 system are anticipated to have a rather tightly bound network structure due to the cross-linkings through Ca2+ ions. |
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