Browsing by Author "BERNAL, L"

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    THERMOGRAVIMETRIC STUDIES OF CHITOSAN DERIVATIVES
    (ELSEVIER SCIENCE BV, 1992) CARDENAS, G; BERNAL, L; TAGLE, LH
    The thermal stabilities of chitosan derivatives (chito; 2-amino-2-deoxy(1-4)-beta-D-glucopyranan) have been studied by thermogravimetry (TG) between 25 and 550-degrees-C under nitrogen flow. The kinetic data thus obtained indicate that the thermostabilities decrease in the order, chito-salicylaldehyde > chito-thioglycolic acid > chito > chito-butanoyl chloride > chito-4-Br-aniline > chito-4-NO2benzene > chito-benzoic acid > chito-benzoyl chloride. The thermal stability apparently depends on the kind of bond established between the chitosan and the reactants. Schiff bases are more stable than amides and alkyl amines. The order of reaction for the thermal decomposition of these chitosan polymers ranges between -0.5 and -1.0. This is probably due to several overlapped processes. The pre-exponential factor, the reaction order and the activation energy of the decomposition for chitosan derivatives have been determined.