• Journal of the Korean Wood Science and Technology
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• 제16권4호
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• pp.70-78
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• 1988

To separate and utilize the main components of hardwood (Quercus mongolica) by organosov pulping (ester pulping), chips were cooked at various conditions such as; the solvent ratio (acetic acid: ethylacetate: water, 50:25:25; 33:33:34; 25:50:25), maximum temperature (165, 170, $175^{\circ}C$), and cooking times (2, 2.5, 3 hr). The pulps were bleached by the sequences of CEDED, C/DEDED, PEDED. Lignin, sugars, and acetic acid were separated from black liquor and washing liquors. 1. The selective delignification at optimal pulp yield (43-45%) was obtained by cooking at acetic acid: ethylace tate: water ratio of 33:34:34 for 3 hr at $170^{\circ}C$. But in this case, kappa no. of the pulp was not reduced under 60 points. 2. Kappa no. of the pulp could be dropped by an acetone wash to remove reprecipitated lignin a t cooked pulp. 3. The unbleached pulps had a brightness of 45-50%, whereas the bleached pulps gave at 88-93% brightness. Tensile, burst, and tear strengths of the bleached pulps were lower than those of kraft pulp, especially in tear strength. The pulps which were bleached with CEDED sequence were higher in strengths than another bleaching sequences. 4. Lignin of 90-95%(lignin base on wood)was separated from black liquor and washing liquors, while the purified sugars and recovery of acetic acid were a low. An organic phase composed of acetic acid, ethylacetate, and water was separated to a two-phase system by proper adjustment of the solvent ratios.

• 펄프종이기술
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• 제47권4호
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• pp.54-59
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• 2015

In this study, effects of kneading concentration on characteristics of hardwood bleached kraft pulp (HwBKP) fibers were elucidated. A laboratory two-shaft kneader was utilized for kneading. Kneading concentration was varied in the range of 15-30% (w/w) and the number of kneading treatment was adjusted between 0 and 6 passes. It was found that kneading concentration influenced fiber characteristics. At 15% of pulp concentration, fiber length slightly increased with increasing the number of kneading passes, while other morphological properties such as fiber width and curl decreased: fiber straightening occurred. In addition, the increase in WRV and the decrease in CSF were the largest at 15% kneading concentration, meanings that fibrillation mainly occurred. In contrast, at higher kneading concentration exceeding 20%, fiber deformation like curl was mainly occurred. Also, at kneading concentration of 20% and 30%, fiber length decreased with the number of kneading passes while other morphological properties such as fiber width, and WRV increased. Severe fiber entanglement was found at 30% kneading, which shall be removed during papermaking.

• 펄프종이기술
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• 제35권5호
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• pp.17-25
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• 2003

The influence of base paper properties and fiber type on coating penetration was studied in terms of characterization of coating holdout using two types of hand sheets as the base paper which were prepared from thermomechanical pulp (TMP) and hardwood bleached kraft pulp(KP) sized internally with alkyl ketene dimmer (AKD). Laboratory rod draw down coater was used for surface sizing and coating application. Characterization of coating penetration was done by measuring the roughness of the backside of coating layer. The backside of the coating was exposed by dissolving the fibers in a solution of cupriethylenedimine (CEO). Data show that internal sizing of base paper is effective and surface sizing is more effective to prevent coating penetration. Comparing between the two types of base papers, backside roughness of coating layer of TMP sheet is much larger and sizing is more effective to reduce coating penetration than those of KP sheet. From the result of water absorption and sizing degree after surface sizing, it seems that internal sizing slows down molecular diffusion much more than capillary penetration, but surface sizing reduces the capillary penetration. Furthermore, predominant mechanism of water into paper of TMP sheet seems to be capillary penetration, but it is molecular diffusion in the case of KP sheet.

• 펄프종이기술
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• 제43권3호
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• pp.59-65
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• 2011

The saw dust of tropical hardwood, Nyatoh(Palaquium Spp.), was used as a raw material for the preparation of the high valued microcrystalline cellulose(MCC). Three pulping methods, soda pulping, Kraft pulping, and acid-sulfite pulping were applied to obtain cellulose from the saw dust. The residual impurities were removed with the additional bleaching processes: (A) $ClO_2{\rightarrow}H_2O_2$; (B) $ClO_2{\rightarrow}O_3$; (C) $O_3$. For the acid treatment for MCC preparation, the $H_2SO_4$, with three concentration, 20%, 40%, 60% were applied and the effects of $H_2SO_4$ concentration on the properties of MCC were evaluated. The results indicated that the MCC obtained by acid-sulfite pulping followed with $O_3$ treatment and 40% $H_2SO_4$ treatment showed less residual lignin, higher brightness and crystallinity than that of Avicel MCC.

• Korean Chemical Engineering Research
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• 제51권5호
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• pp.561-567
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• 2013

본 연구에서는 바이오연료 생산을 위한 헤미셀룰로오스의 회수 목적으로 혼합 하드우드 칩을 크라프트(kraft) 펄핑공정 전에 녹액(green liquor)으로 선-펄핑추출(pre-pulping extraction) 하였다. 본 실험에 사용된 녹액은 황화나트륨과 탄산나트륨이 주요 성분이며, 이 녹액에 목재 건조 질량당 0, 1, 3, 5%의 알칼리($Na_2O$)를 각각 충진하였다. 가혹 조건에 따른 선-펄핑추출액의 구성 성분을 알아보기 위해 추출은 반응시간은 1~2 h로 달리하면서 $160^{\circ}C$ 조건에서 실험을 수행하였다. 선-펄핑추출공정은 헤미셀룰로오스 추출시간과 녹액 주입 정도의 가혹도(severity)에 따라서 하향류 공정(downstream process)에서 활용 가능한 아세트산(acetic acid)과 단당류 농도, 그리고 유기산과 퓨란(furan)과 같은 분해 생성물의 축적 정도가 변한다. 본 연구 결과에서는 알칼리 주입 양이 증가할수록 헤미셀룰로오스에 존재하는 아세테이트(acetate)의 곁사슬과 용해성 및 리그닌의 양은 증가하지만, 추출액에서 탄수화물과 당류는 상당히 감소하였다. 특히 고온수(hot water)로 추출(알칼리 주입 0%)하는 경우 29.80 g/L 이상의 가장 많은 양의 탄수화물이 추출되었으나, 펄프 수율은 가장 많이 감소하였다. 또한 3% 녹액의 추출은 펄프 수율은 증가하였으나 당은 7.08 g/L로 많은 양이 감소하였다. 이 논문에서 얻어진 데이터를 통해 크라프트 펄핑공정에 추출공정 통합을 위한 헤미셀룰로오스 추출 조건을 최적화할 수 있을 것이다.

• 펄프종이기술
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• 제47권4호
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• pp.38-45
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• 2015

Fold cracking is one of quality troubles of coated papers. In this study, the fold cracking of high grammage ($250g/m^2$) coated paper made with the different pulp composition and layer structure of base paper was investigated. The single layered, high grammage base paper was prepared by mixing of hardwood and softwood bleached kraft pulp fibers with the different ratios. The high grammage coated paper showed the higher fold cracking than low grammage coated paper because of the increase in thickness. The increase in the content of softwood pulp fibers reduced the fold cracking in the case of high grammage coated paper. When the creasing process was conducted before folding process, the fold cracking of coated paper decreased. By manufacturing the base paper with multiply structure, the fold cracking of coated paper could be reduced significantly, especially when the BCTMP and OCC were used as a middle layer and the creasing process was carried out. The delamination of layers in base paper affected the fold cracking positively.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.311-316
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• 2006

The role of short fibre pulp - Mixed Harwood, Eucalyptus, Aspen, Birch, etc for the manufacture of different grades of paper is very well recognized. At the same time, lots of efforts are in progress to maximize the advantages while preserving their own special property. Bleached Acacia Kraft Pulp (BAKP) is comparatively new entry but gained quick recognition. BAKP was introduced to the world market by South East Asian suppliers in the late 1990's. This paper discusses in detail the role and opportunities of use of short fibre pulps. A logical technical comparison has been made between BAKP and another short fibre grades. BAKP being a short, thin-walled fibre shows several similarities with Eucalyptus pulp in terms of good bulk and stiffness. Refining energy and strength properties are very similar, but the shorter fibres and thinner cell walls give an outstanding opacity and formation compared to other commercial short fibre pulps. The collapsed and band-shaped nature gives a matchless smoothness, enabling less calendaring and exceptional printing properties. BAKP is shown to give several advantages to fine paper manufactures, compared with a number of established short fibre pulps such as Brazilian and Chilean Eucalyptus, Canadian Aspen and Indonesian Mixed Hardwood. It is important to consider refining and calendaring conditions to achieve optimum performance. For outer layers of multiply board, Acacia gives excellent coverage due to its high opacity and uniform fibre distribution. Its low roughness property gives improved printability. For tissue products, Acacia gives unique property of superior softness both in terms of hand feel and bulk softness. The high fibre population gives an impression of much higher quality due to the higher opacity and good formation.

• Journal of the Korean Wood Science and Technology
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• 제40권2호
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• pp.71-77
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• 2012

Cellulose nanowhisker (CNW) isolated from hardwood bleached kraft pulp (HW-BKP) using sulfuric acid hydrolysis was suspended in polyvinyl alcohol (PVA) and electrospun into composites nanofibers. Transmission electron microscopy (TEM) revealed the CNW to be rod-like, approximately of $16.1{\pm}4.6$ nm wide and $194{\pm}61$ nm long, providing an aspect ratio of about 12, with a particle size distribution range of $662.2{\pm}301.2$ nm. Uniform and high quality CNW/PVA composite nanofibers were successfully manufactured by the electrospinning method. As the CNW loading increases, the viscosity of CNW/PVA solutions shows a minimum at 1% CNW level which subsequently results in the smallest diameter (193 nm) of electrospun nanofibers. The average diameter of the nanofibers increased up to 284 nm with increasing CNW loading. These results suggest that the electrospinning method provides a great potential of manufacturing consistent and reliable nanofibers from CNW/PVA solution for the formation of scaffolds with potentials in future application.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.613-627
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• 2015

Simple methods of conductometric titration and infrared spectroscopy were used to quantify the surface carboxyl content of cellulose fibrils isolated by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. The effects of different cellulose sources, post or assisted-sonication oxidation treatment, and the amount of sodium hypochlorite addition on the carboxyl content of cellulose were reported. This study showed that post sonication treatment had no influence on the improvement of surface carboxyl charge of cellulose macrofibrils (CMFs). However, the carboxyl content increased for the isolated cellulose nanofibrils (CNFs). Thus the carboxyl content of CNFs is different from those of their corresponding bulk oxidized cellulose and CMFs. Filter paper as a CNF source imparted a higher surface charge than did hardwood bleached kraft pulp (HWBKP) and microcrystalline cellulose (MCC). It was considered that the crystallinity and microstructure of the initial cellulose affected oxidation efficiency. In addition, the carboxyl content of cellulose was successfully controlled by applying sonication treatment during the oxidation reaction and adjusting the amount of sodium hypochlorite.

• Current Research on Agriculture and Life Sciences
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• 제31권4호
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• pp.250-255
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• 2013

As a renewable nanomaterial, cellulose nanocrystal (CNC) isolated from wood grants excellent mechanical properties in developing high performance nanocomposites. This study was undertaken to compare the reinforcing efficiency of two different CNCs, i.e., cellulose nanowhiskers (CNWs) and cellulose nanofibrils (CNFs) from hardwood bleached kraft pulp (HW-BKP) as reinforcing agent in polyvinyl alcohol (PVA)-based nanocomposite. The CNWs were isolated by sulfuric acid hydrolysis while the CNFs were isolated by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. Based on measurements using transmission electron microscopy, the individual CNWs were about $6.96{\pm}0.87nm$ wide and $178{\pm}55nm$ long, while CNFs were $7.07{\pm}0.99nm$ wide. The incorporation of CNWs and CNFs into the PVA matrix at 5% and 1% levels, respectively, resulted in the maximum tensile strength, indicating different efficiencies of these CNCs in the nanocomposites. Therefore, these results suggest a relationship between the reinforcing potential of CNCs and their physical characteristics, such as their morphology, dimensions, and aspect ratio.