Effect Of Enzyme Pretreatment On Papermaking Properties Of Poplar High Yield Pulp

In order to solve the resource and environmental problems in China’s paperindustry, high yield pulping technology has been developing rapidly in recent years.High yield pulping technology has many advantages, such as high-fiber resourceutilization, low production cost, and low pollution load, etc. However, the high yieldpulp exists some disadvantages, for example, the lower paper physical strength and thepoor brightness stability, limiting its further application. Enzyme pretreatment on thehigh yield pulp can reduce energy consumption and improve the physical and opticalproperties of the pulp, thus improving the papermaking properties of the high yield pulpand expanding the scope of its application.The cellulase and xylanase were used to modify the APMP and P-RC APMP, thenpapermaking with BKP. The effects of enzyme treatment on beatability of the high yieldpulp was studied and the physicochemical properties of paper were detected.Environmental scanning electron microscope (SEM), fiber quality analyzer (FQA),X-ray diffractometer (XRD)，fourier transform infrared spectroscopy (FTIR) were usedto analysis the changes of the fiber morphology and physical structure of the untreatedand the treated fiber. In this way, the effect of enzyme pretreatment on papermakingproperties of high yield pulp of poplar were thoroughly investigated.The effection of cellulase pretreatment on papermaking properties of APMP pulpof poplar was studied. The experimental results showed that, the suitable beating degreeof APMP pulp papermaking with BKP pulp is45°SR. The pretreatment of APMP candecrease the beating energy consumption by12%～19%, and increace water retentionvalue by12.6%. Breaking length, tearing index, bursting index and folding enduranceof the pulp treated by cellulase were respectively improved by6.1%,44.6%,30.3%,10%, while the brightness and the opacity were slightly decreased. When we improvethe properties of APMP pulp papermaking with BKP pulp, the optimized cellulasepretreatment conditions are as follows: enzyme dosage is30IU/g, addition proportion ofAPMP is60%～80%. The analysis results of FQA, SEM, XRD and FITR showed thatthe fiber of the pretreated pulp are much softer, the fiber length increased, fines contentdecreased and crystallinity increased by1.74%, resulting in the strength properties ofAPMP pulp of poplar improved.The effection of xylanase AU-PE89pretreatment on papermaking properties ofAPMP pulp of poplar was studied. The experimental results showed that， the pretreatment of APMP can decrease the beating energy consumption by20%. Waterretention value increased with the addition of xylanase, and the bursting index andfolding endurance of the pulp treated by xylanase were improved by21%and50%,respectively. The brightness increased by0.9%ISO, while the opacity were clearlydecreased. When we improve the properties of APMP pulp papermaking with BKP pulp,the optimized xylanase pretreatment conditions are as follows: enzyme dosage is20～30IU/g, addition proportion of APMP is60%～80%. The analysis results of FQA, SEM,XRD and FITR showed that the fiber of the pretreated pulp are much softer, the fiberlength increased, fines content decreased and crystallinity increased by3.1%, thus thestrength properties of APMP pulp of poplar is improved.The effection of xylanase AU-PE89pretreatment on papermaking properties ofP-RC APMP pulp of poplar was studied. The experimental results showed that, thesuitable beating degree of P-RC APMP pulp papermaking with BKP pulp is52°SR. Thepretreatment of P-RC APMP can decrease the beating energy consumption by16%.Water retention value increased with the addition of xylanase. Tearing index, burstingindex and folding endurance of the pulp treated by cellulase were improved by23%,27%, and40%, respectively. Breaking length were slightly increased, the brightnessincreased by1.7%ISO, while the opacity was decreased. When we improve theproperties of P-RC APMP pulp papermaking with BKP pulp, the optimized xylanasepretreatment conditions are as follows: enzyme dosage is30IU/g～40IU/g, additionproportion of P-RC APMP is70%～90%. The analysis results of FQA, SEM, XRD andFITR showed that the fiber of the pretreated pulp are much softer, the fiber lengthincreased, fines content decreased and crystallinity increased by2.28%, then thestrength properties of paper is improved.