| summary(En) : | Linter cellulose was treated with ammonium bromide and sodium chloride for the purpose of making researches on effects of the salts on the pyrolysis of the cellulose. Following previous study, the degree of polymerization (DP) and the weight were measured during the heatings in vacuo.
The DPs of the treated samples were rapidly reduced at first, but eventually levelled off. The changes in the DP of both the samples at the initial stage of the pyrolysis are supposed to be caused by random scission of the polymers. Those at the late stage may be explained by a chain mechanism with random-scission initiation and with grafting termination. The obtained activation energies of the random scission and the termination for the bromide-treated sample are 26.8 and 23.0 kcal/mole, respectively. The corresponding pre-exponential factors are 7.4×108 and 1.7×109 sec-1. On the other hand, the determined activation energies of the random scission and the termination for the chloride-treated sample are 32.6 and 19.3 kcal/mole, and their pre-exponential factors are 9.3×107 and 9.9×104 sec-1, respectively.
The weight losses of the bromide-treated sample with the heating are too complicated to yield the kinetic parameters. Those of the chloride-treated sample are shown to be an apparent first-order reaction at the late stage. The activation energy and the pre-exponential factor of the reaction are determined to be 44.3 kcal/mole and 3.5×1014 sec-1. |
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