Abstract

The thermal stabilities of chitin derivatives (chitin; chitin iodine, acetate, phenylthiourea, tosylate, butyl xantate, benzyl xantate, isocyanate hexane, benzoate and benzoylate) have been studied by thermo-gravimetry (TG) between 278 K and 823 K under nitrogen flow. The kinetic data thus obtained indicate that the thermostabilities decrease in the order: chitin-acetate > chitin-phenylthiourea > chitin-iso-cyanate hexane > chitin-butylxantate > chitin-benzoate > chitin-benzylxanthate > chitin-iodine > chitin benzoylate. The thermal stability seems to depend on the kind of bond established between the chitin and the reactant. Tosylate exhibits the lowest Ea. probably due to its property as a good leaving group. Furthermore, chitin-acetate has the highest Ea due to its similarity with the pendant group which enables the macromolecule to achieve better electric resonance stabilization. The reaction order for the thermal decomposition of these chitin polymers is zero. This means that we are concerned with a single step decomposition mechanism. The pre-exponential factor, the reaction order, the decomposition temperature and the activation energy of the decomposition for chitin derivatives have been determined.