Physical characterization of enzymatically modified kraft pulp fibers

Douglas-fir kraft pulps were treated with an enzyme preparation containing both cellulase and xylanase activities. Treatments resulted in the solubilization of 21.1% the xylan and 1.8% of the cellulose. Changes in fiber and paper properties were observed. Monitoring pore volume, degree of polymerization, crystallinity, FT-IR spectra, and scanning electron microscopy helped elucidate changes in fiber composition and morphology. Data indicate a decline in intrinsic fiber strength due to an erosion of the fiber surface. Reduction in paper strength resulted from the collective effects of decreased intrinsic fiber strength and the reduction in the degree of polymerization of a large portion of the hemicellulose component of the fibers, as well as fiber defibrillation and fines hydrolysis. (C) 1997 Elsevier Science B.V.