• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.5
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• pp.95-100
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• 1999

In order to find fungi having high treatment activity of kraft pulp bleaching (E1) effluent without any additional nutrietns, 124 strains of white-rot fungi were isolated from decayed wood samples. The author isolated five fungi(KS-62, MZ-400 , YK-719, YK-472 and Phanerochaete sordida YK-624) having high-decolorization activity of the E1 effluent. Particularly, the fugus KS-62 show the high effect of the decolorization and the degradation of the chlorinated lignin in the E1 , effluent compared with Coriolus versicolor and Phanerochaete chrysosporium.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11a
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• pp.194-204
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• 1999

The use of genetically cloned xylanase acquired from Bacillus strearthermophillus improves bleachability for oak kraft pulps. Combination of xylanase(X). oxygen(O), ozone(Z). peroxide(P), alkaline extraction(Eo. Eop), and chlorination(C/D, D) have been tested in a variety of bleaching sequences. The effectiveness of xylanase pre-treatment(XO) and post-treatment(OX) in oxygen bleaching is mainly compared. With xylanase treatment the brightness increase by 1.5-2.1% ISO in OZEP, OZEoP, OZEopP and OPZP sequences. There is only numerically difference of brightness gains between OX and XO sequences. With xylanase treatment chemical requirements for bleaching decrease by 42.6-48.6% in OC/DEoD sequence and 47.9-54.7% as active chlorine in OC/DEopD sequence at the same brightness. the reduction of bleaching chemicals is higher in XO sequence than those in OX sequence. Following xylanase treatment the viscosity increases from 11.7-12.0 mPa·s to 12.4-13.5 mPa·s and the brightness stability is considerably improved however the difference of effectiveness between XO and OX sequence is not present. Compared to tensile index vs tear index, the physical properties are similar for TCF bleaching sequences with and without xylanase treatments. However in OC/DEoD and OC/DEopD sequences the physical properties decrease with xylanase treatment. There is no difference in the physical properties between XO and OX sequences. COD, BOD and color of bleaching effluents increase slightly with xylanase treatment, however the discharge of COD end-load into environmental impact decrease.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.4
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• pp.21-27
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• 2014

As a part of the study on manufacture of low density paper by organic bulky agent treatment, the effects of cationic fatty acid bulky agent on physical and optical properties of handsheets were elucidated. The research on change of physical and optical properties of paper samples according to bulky agent concentration, pulp type, and pulp combination were carried out. The results demonstrated that an increase of the concentration of cationic fatty acid bulky agent was proportional to an increase of the bulky properties of paper samples while tensile strength decreased. Also, the more the treated concentration of cationic fatty acid bulky agent increased, the more the ISO brightness of paper samples decreased while the opacity increased. The effectiveness of bulky agent with softwood bleached kraft pulp (SwBKP) was higher than that with hardwood bleached kraft pulp (HwBKP). In addition, the effectiveness with mixed pulps was higher than that with single pulp.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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• pp.53-60
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• 2010

Kudzu vine (Pueraria lobata) is a perennial plant and spreads all around in South Korea. Recently the use of leaves, stems and roots of kudzu vine has been investigated in many fields. However, the research on kudzu fibers has not been performed in korean pulp and paper industry. As the stems and roots of kudzu were estimated to contain cellulosic fibers, the possibility of producing a raw material from kudzu fibers in pulp and paper mills was investigated in this study. The stems and roots of kudzu were collected in woods, and then the chemical composition and ash contents was measured. To acquire kudzu pulp, kraft pulping and bleaching of kudzu roots were carried out sequently. After making kudzu pulp, freeness and fiber length were measured, and handsheets was also prepared with kudzu pulp and the properties of handsheets were determined. Consequently, kudzu fibers have lower holocellulose contents than wood fibers and other non-wood fibers. Average fiber length is shorter than that of Sw-BKP, but shows the same level as that of Hw-BKP. The handsheet made from kudzu pulp shows the bulkier structure than those made from Hw-BKP and Sw-BKP.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.5 s.108
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• pp.69-77
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• 2004

Degradations of pine, yellow poplar and sweet gum by two fungi, Pycnoporus cinnabarinus and Trichophyton rubrum LSK-27 were investigated. P. cinabarinus degraded pine block samples much faster than T rub rum LSK-27, whereas P. cinnabarinus and T rubrum LSK-27 degraded yellow poplar and sweet gum at almost the same rate. In an effort to get a better understanding of how fungi degrade lignin in wood, contents of various functional groups were analyzed. After three-months of degradation of pine flour by these fungi, the following changes were observed: an increase in condensed phenolic OH group and carboxylic acid group content, a decrease in the guaiacyl phenolic OH content, and little change of aliphatic OH group content. Further studies in the degradation of pine flour by P. cinnabarinus indicated that the increase in condensed phenolic OH group content and the decrease in guaiacyl phenolic OH group content occurred in the first month of the degradation. The changes of functional group contents in the degradation of unbleached softwood kraft pulp by P. cinnabarinus had the same trends as those in the degradation of pine flour. That is, structural alteration of lignin due to the kraft pulping process had little effect on how P. cinnabarinus degraded lignin.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.1
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• pp.31-38
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• 1999

Adsorption of polymeric flocculants and dry strength agents onto the surface of papermaking fibers is critical for their effective utilization since the polymeric substances not adsorbed on fibers or fines keep recirculating in the papermaking system to cause various operational difficulties and loss of raw materials. Problems associated with the unadsorbed polymeric substances generate great attention because unprecedent interests in utilization of recycled papers and papermaking system closure. In this study, to understand the effects of recycling on the adsorption propensity of cationic polyacryamide (PAM) dry strength resin onto hardwood bleached kraft pulp fibers and fines a systematic approach was followed. Never dried bleached hardwood kraft pulp was recycled in two different ways. In mode one recycling experiment never dried pulp was beaten then recycled three times by employing simple drying and disintegrating steps. In mode two recycling experiment beating of the recycled pulp was carried out after each recycling step. Adsorption of cationic PAM on fibers and fines was evaluated employing Kjeldahl nitrogen analysis method. The influence of recycling on water retention value, carboxyl content, sheet density and tensile strength of the pulp was examined. As the number of recycling increased, water retention value of the fiber was reduced due to hornification and this in turn caused a decrease in adsorption of cationic PAM. On the other hand, the carboxyl content of the recycled fibers increased because of the oxidation of fibers occurred during drying, and this caused an increase in adsorption of cationic PAM. Because of these two opposing factors the adsorption of the cationic PAM on the recycled fibers decreased and then increased slightly at third recycling step. Increase of PAM adsorption, however, did not provide did not provide and strength improvement for the recycled pulp fibers indicating greater influence of the honification on interfiber bonding.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.10a
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• pp.305-311
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• 2008

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.31-36
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• 2006

Tritium has been used to directly measure the exchangeable hydrogen in bleached softwood kraft pulp. The hydrogen atoms associated with hydroxyl groups in pulp or with water contained in the pulp can dissociate and exchange with the hydrogen atoms in bulk water. Tritium is a radioactive isotope of hydrogen and behaves almost identically to it. The distribution of tritium between pulp and water ($k_{pw}$) can be easily measured and becomes an index of the protons available fur hydrogen bonding. Bleached kraft pulp was refined in a PFI mill to a range of freenesses. Tritiated water was added and the amount exchanged measured. There was a slight steady increase in $k_{pw}$ until approximately 300 CSF; $k_{pw}$ then rose sharply between 300 CSF and 100 CSF. This rise appears to correlate with FSP. It is likely that the action of refining on the fiber reaches a threshold at about 300 CSF causing the fiber surface to break open creating exponentially more surface area. This theory is visually confirmed through light microscopy. The slow increase in fibrillation of the fibers above 300 CSF correlates with the increase in $k_{pw}$. Beyond the threshold of 300 CSF a dramatic difference in fibrillation is shown, also corresponding with the large increase in $k_{pw}$. The freeness difference around 300 CSF is small, but the change in fiber properties is extreme within this region. This change in properties could lead to sheet breaks and other disruptions when producing products around the threshold. This study leads to a better understanding of how fiber changes during refining, resulting in a practical benefit of target freeness determination. Presently, freeness is selected based on product quality and on some measure of runnability. Yet, there are other considerations, demonstrated by the extreme change in fiber properties around 300 CSF.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.5
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• pp.47-56
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• 1999

Tensile energy absorption in paper has long been measured as the area under the load-elongation curve. Little effort has been made to define where and how that energy is used within the paper itself. Characterization of tensile energy absorption in paper is discussed. Multiple small elements within newsprint and kraft sack have been defined and the energy absorbed in those elements are discussed. The tensile profiles of the weak paper, newsprint, and the tough paper, kraft sack, are presented as separate strain profiles, stress profiles, and strain energy density profiles. This allows a complete analysis of the energy absorption of both papers for comparison or contrast.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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• pp.35-40
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• 2010

Variations in hexeneuronic acid content in hardwood alkaline pulps were investigated to evaluate their contribution to kappa number. Out of diverse chemical pulps the highest hexeneuronic acid content were measured in yellow poplar kraft pulping, which was assumed to enhance ca. 7.0 of kappa number determined by acid permanganate consumption. In yellow poplar soda-anthraquinone pulping, hexeneuornic acid was contributed to increment of 5.0-6.0 kappa number. In eucalyptus alkaline pulping, hexeneuronic acid content was not significantly different from soda-anthraquinone pulping. Increment of Kappa number by hexeneuronic acid was 4.5-5.6 depending on pulping method and pulping time at target temperature.