Preparation of Chitosan Copper Complexes: Molecular Dynamic Studies of Chitosan and Chitosan Copper Complexes

摘要

This work studied the effect of copper ions concentration chelated by functional groups in chitosan on its molecular dynamic. Chitosan Copper complexes prepared having different copper concentrations by the electrochemical oxidation technique in aqueous-acetic acid medium. It was carried out at constant voltage (2 volt.) at room temperature at different electro-oxidation time. The result of partial elemental analysis and XRD studies of chitosan copper complexes compared with chitosan confirmed that the percentage composition of the complexes were found to be depend on the time of electrolysis which is in good agreement with our previous work. Interpretation of the effect of copper ions concentration on molecular motion of chitosan studied using dielectric spectroscopy, the results showed that dielectric constant of chitosan is higher than that of chitosan copper complexes. This may be attributed to the relatively fast segmental motion of chitosan chain slowed down by complexation with copper ions of all complex samples. Calculated activation energy from Arrhenius variation showed increase in value with increasing the copper concentration and all in the range that required for ionic conduction. Temperature dependence part of dielectric parameters gives very useful representation in the glass transition temperature determination.