Thermal Stability and Degradation of Chitosan Modified by Acetophenone

Abstract

N-(Methylphenylmethylidenyl) chitosan (MPMC) polymer was synthesized by chemical modification of chitosan. The chemical structure of the modified polymer was characterized by IR, 1H NMR and elemental analysis. Thermogravimetric reveals that the thermal stability of chitosan polymer is greater than MPMC polymer. The activation energies of thermal degradation of chitosan and MPMC polymers determined using Arrhenius relationship. Thermal degradation of MPMC polymer was studied and the products of degradation were identified by GC–MS technique. It seems that the mechanism of degradation of MPMC polymer is characterized by elimination of low-molecular weight radicals. Combination or recombination of H· or OH− with these radicals and random scission mechanism along the backbone chain are the main source of the degradation products.