Change in Degree of Polymerization of Wood Pulp with Cellulase Hydrolysis

Abstract

A study was made of the changes in degree of polymerization (DP), water retention value (WRV), and yield when high α-sulfite pulp (α-SP) is beaten or swollen with zinc chloride or sodium hydroxide and treated with cellulase. For a sample swollen with sodium hydroxide, the decrease in DP is large, and the DP decreases easily to a value which corresponds approximately to the level of DP in acid hydrolysis. On the other hand, a sample treated with zinc chloride solution shows a small decrease, while a beaten sample indicates an intermediate DP value. It is assumed from these results that sodium hydroxide swells the amorphous region of the fiber greatly but has little effect on the crystalline region, whereas zinc chloride swells the crystalline region but its swelling effect on the amorphous region is not very great. Cellulase can be utilized for analyzing the structure of cellulose fiber.