Exploring crystalline structural variations of cellulose during pulp beating of tobacco stems.

In this work, crystalline structural variations of cellulose during pulp beating of tobacco stems were characterized through X-ray diffraction (XRD) and FT-IR spectroscopy. The results showed that the correlation between the cellulose crystallinity index and the degree of beating was not a linear but an initially upward and then downward trend followed by a repeating fluctuation as a result of the beating action on amorphous regions first and then on crystalline cellulose. It was proposed that the whole beating process might be presumably divided into two phases in the case of the evolution of the crystallinity index. The crystallite sizes of 101 and 101¯ lattice planes showed an obvious fluctuation during the beating while the crystallite sizes and d-spacings from representative 002 lattice planes exhibited little change. Complementally, FT-IR characterization of cellulose structural properties further proved that the crystallinity index was highly affected by mechanical beating and the intact beating process might be divided into two stages characteristic of a first ascending and then descending tendency.