| PDF : |  18020079.pdf |
| title(En) : | Effect of the Thermal Treatment on Wood Hemicelluloses. VI. Studies on the Thermal Analysis of Arabinogalactan, and O-Acetyl- and Deacetylated-galactoglucomannans (in English) |
| author(En) : | Kazumasa Shimizu, Fumiyuki Teratani, Mieko Hashi, Kango Miyazaki |
| information : | Mokuzai Gakkaishi 18(2), 79-84 (1972)
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| assort : | Original Article |
| summary(En) : | The thermal degradation of the arabinogalactan and O-acetyl- and deacetylated-galactoglucomannans which had been elaborately prepared was investigated using the techniques of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) in air, flowing nitrogen and vacuum at a heating rate of 2.5°C/min. Values of kinetic parameters were calculated on the basis of TGA under vacuum.
These results showed that all the three samples pyrolyzed in three reaction stages, and that the O-acetyl-galactoglucomannan was the most thermally unstable. On the pyrolysis of the arabinogalactan and deacetylated galactoglucomannan, a first-order reaction zone with the low activation energy (6-8 kcal/mole) was found before the region in which the rapid weight loss took place. In the latter region, the degradation was followed by another first-order with the activation energy of 28.0 kcal/mole for the deacetylated galactoglucomannan, and of 34.8 kcal/mole for the arabinogalactan, respectively. For the O-acetyl-galactoglucomannan, the first-order reaction zone with the high activation energy (38.2 kcal/mole) was found which might possibly be caused by the hydrolysis of the O-acetyl groups. The O-acetyl groups had a profound effect on the thermal degradation of the galactoglucomannan in the atmospheres used except the nitrogen.
The corresoonding DTA curves seemed to reflect the distinct reaction zones as described above. |
