Pyrolysis-Crystallinity Relationships in Cellulose

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Abstract
During pyrolysis of pure cellulose, the Crystallinity Index (Crl) remained fairly constant over more than 50% weight loss before dropping rapidly as the X-ray pattern deteriorated. With samples first treated with trace quantities of inorganic salts, heating first increased the Crl—the results implying a preferentially catalyzed decomposition of the amorphous regions. Swelling cellulose in liquid ammonia eliminated the crystalline diffraction pattern, but heating restored a considerable degree of order. The initial weight loss rate in the swelled material was considerably accelerated and the ultimate char residue reduced. The results support the suggestion that inter-ring cross-linking leading to enhanced char formation will occur preferentially in the ordered rather than the disordered regions of natural cellulose.