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تسجيل

Thermal Degradation of Cellulosic Materials

المؤلف:  A. Ravve

المصدر:  Principles of Polymer Chemistry

الجزء والصفحة:  P661-662

2026-03-02

396

Thermal Degradation of Cellulosic Materials

The degradation of cellulose triacetate in vacuum was analyzed with the aid of chromatography, mass spectrometry, infra-red, and NMR spectroscopy [517]. The mechanism of degradation was proposed by Scotney to consist primarily of deacetylation in the polymer chain and scission of the chain at the 1,4 glycosidic linkage between the pyranose rings [517]. The type of products that are formed depends upon the degradation temperature. At temperatures above 250C but below 350C, unstable intermediates form. Continued heating results in loss of carbon monoxide, carbon dioxide, and acetic acid, and eventually end in formation of tar. Heating above 350C causes condensation of radical intermediates, cross-linked aromatic, and hydroaromatic ring systems. This can be illustrated as follows:

The mechanism of thermal degradation of cellulose appears to include two reactions. The first reaction consists of dehydration and the second one of scission of C–O bonds in the chains between the rings or within the rings [457]. This can give rise to levoglucosan [457]: