Decoration And Modification Of Bio-enzyme Treatment On Properties Of Fast-growing Poplar APMP Pulp

Alkaline peroxide mechanical pulp （APMP） is a kind of high yield pulpdeveloped with the comprehensive utilization of wood and the promotion of cleanproduction techniques. The pulping process has a lot of advantages, such as the lowconsumption of chemicals, the simple operating procedure and the low pollution load.However, the disadvantages of APMP are also obvious, including the lower paperphysical strength, the higher energy consumption of refining and the poor brightnessstability.APMP was treated by xylanase, cellulose, the mixture of xylanase and celluloserespectively in this subject. The purpose was to investigate the effects of the differentenzymes or mixed enzyme on pulp physical properties, inhibition of brightnessreversion, saving energy consumption and reduction of production costs.In order to optimize treatment conditions of APMP by xylanase in the study, afive factors and four levels orthogonal L16（45） were used. The five factors includedenzyme dosages, temperatures, pH, treatment times and pulp concentrations. Theenzyme dosages were20IU/g,40IU/g,60IU/g,80IU/g, absolute dry pulp as areference; pH values were6,7,8and9; temperatures were45℃,50℃,55℃,60℃;pulp concentrations were5%,6%,7%,8%; treatment times were60min,90min,120min,150min, respectively. In the study, the fiber morphylogy, the degree ofcrystallinity of the fibers of the pulp fibers, the paper strength properties and opticalproperties were investigated. In the orthogonal experiments, the ninth and thefourteenth runs are the optimum processing conditions. Analysis of the xylanaseoptimized processing conditions are as follow: enzyme dosage is60IU/g, temperatureis50℃, enzyme treatment times is90min, pH is8. Under the optimized condition,breaking length is4.07Km, tearing index is4.85mN.m².g^-1, burst index is2.94KPa.m²g^-1, brightness is71.75%ISO.In this subject, the optimized conditions of APMP treatment by cellulase and themixed enzymes of cellulase and xylanase were studied. A five factors and four levelsorthogonal experiment L16（45） was also used in this part. Enzyme dosages,temperatures, pH, treatment times and pulp concentrations were used as variables tostudy the fiber morphylogy, the degree of crystallinity of the fibers of the pulp fibers, the paper strength properties and optical properties. In the orthogonal experiments, thethird, eighth and the eleventh runs are the optimum processing conditions. Analysis ofthe cellulase optimized processing conditions are as follows: enzyme dosage is60IU/g, temperature is55℃, enzyme treatment times is90min, pH is8. Under theoptimized condition, breaking length is4.16Km, tearing index is4.61mN.m².g^-1,burst index is2.63KPa.m²g^-1, brightness is71.35%ISO.Analysis results of FQA, environmental scanning electron microscopy analysisand X-ray diffraction showed that cellulase and xylanase can improve the propertiesof pulp fiber, and the fiber was soft and flexible. After treatment by the xylanase, thedegree of crystallinity was increased. However, the degree of crystallinity wasdecreased after treatment by the cellulose.