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| PDF : |  24040243.pdf |
| title(En) : | Viscosimetric and Gravimetric Study on Pyrolysis of Cellulose Treated with Ammonium Phosphate and Sodium Borate (in English) |
| author(En) : | Toshimi Hirata, Hajime Okamoto, Kazuo Naito |
| information : | Mokuzai Gakkaishi 24(4), 243-249 (1978) |
| assort : | Original Article |
| summary(En) : | Linter cellulose was treated with two kinds of fire retardants for cellulosic materials, diammonium hydrogen phosphate and sodium tetraborate decahydrate, in order to carry out studies on the effects of the salts on the pyrolysis of the cellulose. The degree of polymerization (DP) of the treated samples which were heated in vacuo was measured by viscosimetry. Furthermore, the weights of the untreated and treated samples were continuously measured with a thermobalance while being isothermally heated in vacuo. The change in the DP of the borate-treated cellulose with the pyrolysis can be explained by the same chain mechanism with random-scission initiation and grafting termination as previously shown for the untreated cellulose. The observed leveling off DP was higher than the untreated one and varied with temperature, being shown to be ascribable to a stationary state between the reactions. The weight loss with the pyrolysis was irregular at the early stage of the heating but expressed as a first-order reaction at the late stage. The activation energies of the initiation, the termination, and the weight loss are estimated to be 29.6, 20.5, and 49.9 kcal/mole, respectively, and the corresponding pre-exponential factors are 1.6 × 107, 2.5 × 105, and 2.0 × 1016 sec-1. For the phosphate treated cellulose, however, the leveling off DP was not found because of the insoluble sample which was long heated, so the chain mechanism was inapplicable. The weight loss at the late stage may be expressed as an apparent first-order reaction. The obtained activation energies of the random scission and the weight loss are 24.8 and 40.7 kcal/mole, and the pre-exponential factors of these reactions are 4.6 × 5 and 6.9 × 1013 sec-1, respectively. For the untreated cellulose, the activation energy and the pre-exponential factor of the weight loss as an apparent first-order reaction at the late stage are determined to be 44.7 kcal/mole and 3.9 × 1013 sec-1. |