Thermal properties of cellulose acetate and its complexes with some transition metals

Different samples of cellulose triacetate-metal ion complexes were prepared from different metal salts. The products were characterized by LR spectros copy, with emphasis on the complex formation. TGA and DTA of cellulose tria cetate (CTA) and its complexes with Ni(ZI), Co(TI), Cu(II) and Cr(III) chlo rides were investigated in the temperature range from room temperature to 5 50 degrees C. The obtained TGA curves show that these samples degrade therm ally in three steps, which are attributed to dehydration, fragmentation of the macromolecular structure (the main thermal degradation step), and the c arbonization of the product to ash. It is found that the main degradation s tep follows first-order kinetics. The complexation of cellulose acetate wit h metal ions increased its thermal stability. The calculated activation ene rgies varied in the following sequence: CTA-Cu(II) > CTA-Ni(II) > CTA-Co(II ) > CTA-Cr(III) > CTA. This observation was attributed to the electronegati vity of the metal ion and the strength of the bond between the cellulose ac etate and the metal ion.