• Fibers and Polymers
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• 제7권1호
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• pp.26-29
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• 2006

Samples of kenaf (Hibiscus cannabinus) grown in Malaysia were examined to determine the kraft pulp and paper-making properties of their bast (or bark) fibers. Using kraft pulping process showed that bast fibers were relatively easy to cook resulting good pulp yields in the range of 45-51 %. The bast pulp produced sheets with great density, tear index and dry zero-span breaking length. Kenaf bast fiber is considered promising for production of high-grade printing, writing and specialty papers.

• Journal of the Korean Wood Science and Technology
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• 제27권4호
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• pp.65-71
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• 1999

This study was carried out to investigate the effect of xylanase pretreatment of the unbleached hardwood kraft pulp during the conventional Chlorine-Extraction- Hypochlorite (CEH) bleaching on pulp property. Optimum bleaching condition was evaluated by using Novozym produced from the fungus Humicola insolens. Also the effect of chelating agent prior to enzyme treatment was analyzed. The kappa number of enzymatic bleached pulp at the enzyme charge 10 IU/ml was slightly similar to that of bleached pulp without enzyme. By enzyme treatment, the chlorine charge in conventional CEH bleaching process of hardwood KP could be reduced by 17%, while no adverse effect on pulp yield and strength was. The optimum condition for enzyme pretreatment was 10 IU/ml xylanase charge, 3 to 4 hrs treatment, and 2% pulp consistency. In sugar composition in the enzyme pretreated pulp, arabinose and mannose were not much different, but more xylose was retained. This high content of hemicellulose in pulp seems to play an important role in pulp properties. The pulp pretreatment by chelating agent prior to enzyme treatment could improve the enzyme activity and enhance the bleaching effect at 0.2% diethylenetriamine pentaacetic acid (DTPA) charges.

• 펄프종이기술
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• 제44권6호
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• pp.1-8
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• 2012

This study was carried out to explore optimum use of the products generated from the National Forest Management Operation (NFMO) as raw materials for kraft pulp. First of all, different wood species from NFMO were randomly mixed, and then they were used to make kraft pulp under the specified condition. All kraft pulps made from the mixed species displayed equal physical properties to those from foreign wood chips used in Moorim P&P Co. Ltd. For optical properties, most of the unbleached pulps had high brightness but the pulp made from wood species containing chestnut tree showed the lowest brightness due to its high kappa number. Finally, the products from NFMO had little negative effects on the properties of kraft pulps. This means that they could be used as complementary raw materials for kraft pulps with foreign wood chips.

• 펄프종이기술
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• 제40권5호
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• pp.27-35
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• 2008

In order to determine the most appropriate recycling line to treat old corrugated container (OCC) to substitute unbleached kraft pulp (UKP) for the manufacture of kraft paper, three recycling lines were evaluated in pilot scale tests. The recycling line consisting of kneading, flotation, washing, dispersion and screening steps was able to produce pulp with acceptable appearance. Kneading was shown to be more efficient treatment to reduce specks than dispersion. In addition, 0.2 mm slot screen was very effective to remove specks. Severe damages on fiber morphology such as shortening of fiber and formation of fines were not observed during mechanical treatments such as kneading and dispersion. Most of strength properties of the kraft paper produced with the recycled pulp were found to be slightly increased after treated in the recycling lines.

• 펄프종이기술
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• 제33권4호
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• pp.49-54
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• 2001

This study was carried out to acquire basic data for the bleaching of bamboo chemical pulp. Bamboo chemical pulps (alkaline sulfite (AS)-anthraquinone (AQ) pulp, Kraft pulp) were bleached with two kinds of multistage bleaching methods (CEDED, PDED) using the various kinds of bleaching agents. And, physical properties of bleached pulps were investigated. The conclusions obtained from the results were as follows; The yield of AS-AQ pulp bleached with four-stages bleaching method using the hydrogen peroxide and chlorine dioxide as a bleaching agents was higher than the other bleached pulps. The brightness of kraft pulp bleached with five-stages bleaching method using the chlorine and chlorine dioxide as a bleaching agents was higher than the other bleached pulps. The physical properties of kraft pulp bleached with four-stages bleaching method using the hydrogen peroxide and chlorine dioxide as a bleaching agents was higher than the other bleached pulps.

• 펄프종이기술
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• 제33권5호
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• pp.25-29
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• 2001

Dimethyldioxirane (DMD), which is a source of active oxygen, is effective agent that can be used in chemical pulp bleaching. In this study, delignification of kraft bagasse pulp has been carried out by using DMD. The effect of the applied charge of DMD (as active oxygen) and pH of the delignification medium were studied. The optimum conditions of the applied DMD charge and pH of the delignification reaction were achieved at pH range from 8~9, 2% of DMD (as active oxygen) and the rest of delignification reaction conditions were $25^{\circ}C$, 60 min, and 12% pulp consistency. The development of brightness per unit kappa number removal (ΔBrightness/ Δ Kappa number) has highest value at the optimum condition. The study showed that the reactivity of kraft bagasse pulp be enhanced to wards alkaline hydrogen peroxide bleaching by pulp treatment with DMD.

• 펄프종이기술
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• 제30권1호
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• pp.44-58
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• 1998

This study was carried out to bleach the Oakwood kraft pulp without the elemental chlorine using the xylanase or wastewater(We : wastewater enzymes) effluented from the submerged biofilter reactor containing the fungi, Phanerorhaete sordida YK-624. So in this research, the proper treatment conditions (pH, temperature, dosage and time) were investigated respectively. And after the various kinds of multistage bleaching of pulps, the properties of pulps were tested. From the experimental results, we can conclude as follows. In the treatments of Oakwood kraft pulps with xylanase, the proper pH, temperature, enzyme dosage and time were 8.0, $35^{\circ}C$ , 400 EXU/kg and 1 hr. respectively. And in the case of treatment with a wastewater(We) effluented from the submerged biofilter reactor, the proper pH, temperature and time were 5.5, $37^{\circ}C$ and 2 hr. respectively. On the other hand, Oakwood kraft pulps were bleached by the method of a multistage bleaching using xylanase or We instead of elemental chlorine Consequently the strengthes and brightnesses of pulps bleached by the method mentioned above were lower than those of pulp bleached by the conventional method using the elemental chlorine. But it is possible to improve the brightnesses through the increase of chlorine dioxide dosage or use of hydrogen peroxide in the final bleaching stage.

• 펄프종이기술
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• 제30권3호
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• pp.84-96
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• 1998

This study was carried out to bleach the Pinewood kraft pulp without the elemental chlorine using the xylanase or wastewater(We:wastewater enzymes) effluented from the submerged biofilter reactor containing the fungi, Phanerochaete sordida YK-624. So in this research, the proper treatment conditions(pH, temperature, dosage and time) were investigated respectively. And after the various kinds of multistage bleaching of pulps, the properties of pulps were tested. From the experimental results, we can conclude as follows. In the treatments of Pinewood kraft pulps with xylanase, the proper pH, temperature, enzyme dosage and time were 8.0, $35^{\circ}C, 400EXU/kg and 3 hr. respectively. And in the case of treatment with a wastewater(We) effluented from the submerged biofilter reactor, the proper pH, temperature and time were 5.0, $37^{\circ}C and 3 hr. respectively. On the other hand, Pinewood kraft pulps were bleached by the method of a multistage bleaching using xylanase or We instead of elemental chlorine. Consequently, the strengthes and brightnesses of pulps bleached by the method mentioned above were lower than those of pulp bleached by the conventional method using the elemental chlorine. But it is possible to improve the brightnesses through the increase of chlorine dioxide dosage or use of hydrogen peroxide in the final bleaching stage.

• Journal of the Korean Wood Science and Technology
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• 제35권6호
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• pp.166-174
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• 2007

효소 전처리에 의한 침엽수 Kraft 펄프의 표백 효율을 살펴보고자 Trichoderma reesei에서 2종류의 xylanase를 cloning하였다. Cloning된 xylanasel과 xylanaseII 유전자를 E. coli에서 발현시켜 29kDa의 재조합 단백질인 XYNI과 29.5 kDa의 XYNII를 생한하여 정제하였고, Rumicoccus albus로부터 cloning되어 변형된 50kDa의 EGIV-CBDII를 동일한 방법으로 cellulase를 생산 정제하였다. 정제된 효소들을 각각 xylan과 CMC를 기질로하여 효소 활성도를 측정한 결과 XYNI이 XYNII보다 효소활성이 더 높았으며, EFIV-CBDII 또한 높은 활성을 나타내었다. 이렇게 생산 정제된 xylanase와 cellulase를 이용하여 침엽수 Kraft 펄프를 대상으로 연속처리에 의한 biobleaching test를 실시하였다. XYNI을 처리하였을 때 백색도는 29.9% 증가하였고, XYNI를 1차 처리한 후 2차로 EGIV-CBDII를 처리하였을 때 백색도는 1차 처리구에 비해 9.1% 증가하였다. 그 후 3차 XYNI를 처리 하였을 때 2차에 비해 7.3%의 bleaching의 효과를 볼 수 있었다. 또한 Kappa No.는 처리단계에 따라 8.1, 4.6 그리고 3.2% 각각 지속적으로 감소하였다. 이 실험결과를 통해 재조합 효소 XYNI과 EGIV-CBDII를 함께 이용하여 Karft 펄프에 대한 biobleaching의 상승효과를 확인하였다.

• 펄프종이기술
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• 제44권5호
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• pp.63-71
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• 2012

This study was carried out to investigate pulping properties of the forest biomass arising from the national forest management operation. The forest biomass was collected and classified into many groups according to their species and age. After the chips were made from the forest biomass, the measurement of chip size and chemical analysis were performed. To make the pulps from the forest biomass, the kraft pulping was applied and thereafter the physical and optical properties of kraft pulps were measured. The pulp fibers from the forest biomass had the similar mean fiber length, but their properties became different according to wood species and ages. Differently from the other species, kraft pulps from chestnut wood had the highest kappa number. Acacia, paulownia and chestnut woods made kraft pulps with lower tensile strength and brightness than the others. It could be concluded that acacia, paulownia and chestnut woods must be screened out in order to make a good quality of kraft pulps while being collected during Forest Management Operation.