Structural Changes in Cellulose during Papermaking and Recycling

Recent advances in understanding the structure of cellulose are used as the basis for analyzing the structural changes that occur in pulp fibers during papermaking, particularly in the drying stage. These changes are responsible for the degradation of papermaking properties, and they must be reversed during recycling if the maximum papermaking potential of the virgin fibers is to be recovered. A number of studies have assessed the structural transformations that can occur in cellulosic fibers upon exposure to elevated temperatures. The researchers have invariably observed that the changes occur at the secondary and tertiary levels of structure, the levels that can have significant effects on the properties of fibers. In addition, some studies have focused specifically on the structural effects of recycling; clear correlations of structural change with changes in paper characteristics have been reported. The results of the various studies point to directions for further investigations into enhancing the recovery of papermaking value from recycled fibers.