Surface and pore structure modification of cellulose fibers through cellulase treatment

The surface and pore structure of cellulose fibers have a significant impact on the properties and performance in applications. Cellulase enzymatic hydrolysis of cellulose fibers can result in changes to the surface and pore structure, thus providing a useful tool for fiber modification. This research characterizes these changes using various test methods such as fiber dimension, water retention value (WRV), hard-to-remove (HR) water content, freezing and nonfreezing bound water content, polymer adsorption, and crystallinity index. For a high-dosage cellulase treatment (600 U/g dry solid), the fiber length was significantly decreased and the fibers were "cut" in the cross direction, not in the axial direction. The swelling capacities as measured by the WRV and HR water content increased for the high-dosage treatment. Three independent measurements (nonfreezing bound water, polymer adsorption, and crystallinity index) are in good agreement with the statement that the amorphous regions of cellulose fibers are a more readily available substrate relative to crystalline regions.