Action Mechanism of the Improvement of Printability for Eucalypt Bleached Kraft Pulp Pretreated by Cellulase

摘要

Enzymatic refining of eucalypt bleached kraft pulp with the cellulase NOV476 was studied. The effects of this cellulase on the physical properties of pulp, fiber shape and fiber morphology of the eucalypt bleached kraft pulp in different application conditions were discussed. The results show that, with the increase in the amount of enzyme, tensile strength index, burst index and TEA index of paper are increased and then decreased; elongation and tear index of paper have been declining, Zeeil tensile strength index has been an upward trend. Without beating the pulp sample, gradually increases as the amount of enzyme, the average fiber length and the average fiber width are gradually reduced, while mean kink index substantially constant. Number of vessels in fiber overall reduced tendency reaches a minimum in the amount of enzyme 0.5μ/g, the phenomenon is most obvious. In the same conditions of beating time, gradually increases as the amount of enzyme, the average fiber length is gradually reduced, an average fiber width is gradually increased, the mean kink index reaches a maximum in the amount of enzyme is 0.5μ/g. Number of vessels in fiber overall reduced trend. Eucalyptus is one of the fast growing tree species in tropical and subtropical. Due to its short growth cycle, making out of the good air permeability of the pulp, high opacity, good absorption and good formability of sheet, so many countries as a system eucalyptus the main raw material for pulp and paper. But because of the thickness of eucalyptus fiber, the big and hard catheter, normal beating process is very difficult to make break it, and so bring some bad effects will give performance and printability of paper products. Enzymatic beating is the use of high activity of hemicellulase and cellulase pretreatment of the pulp before beating, making surface of the fiber to achieve some degree of activation and relaxation, so as to promote the water-absorbing swelling of the fibers and fine fibrosis. In the subsequent mechanical force, the fibers are cutting and brooming, to increase the binding force between the specific surface area of the individual fiber and the fiber molecule, so that the physical properties of the paper are improved in the subsequent papermaking process, thereby improving the performance of paper [4, 6]. This study adopts the efficient NOV476 cellulase enzymatic modification of eucalyptus BKP pulp, in order to improve the physical properties, and improve the quality of the paper.