• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.1-8
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• 2001

Paper consists of fiber network and paper properties were highly affected by fiber characteristics. Many researchers have tried to relate fiber and paper properties. Softwood and hardwood fiber's are quite different in their properties. Generally, softwood fiber's are longer and more flexible than hardwood fibers. At present, many paper mills make mixed paper with softwood and hardwood fibers except for special grade. During fracture some fiber's are broken and others are pulled out. In this paper, the number of broken and pulled out fiber's during fracture is analyzed depending on the mixing ratio of softwood and hardwood fiber's. Fiber length, curl, kink, coarseness, WRV and formation index were measured. Double-edged strength samples were prepared to observe the number of broken and pulled out fiber's. Mixed paper strength was decreased with increasing hardwood fibers ratio. During fracture, softwood fiber's were more likely broken and hardwood fibers were more likely pulled out. The strength of paper which consists of softwood fibers was determined by fiber's broken strength and that of hardwood fibers by fiber's debonding strength. Paper strength was changed depending on the fiber's bonding capability. If the fiber is longer and more flexible, the fiber network becomes stronger and stiffer.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.37-42
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• 2003

Physical properties of paper can be explained in terms of the changes in fiber's morphological properties. As the paper machine speed increases, the basis weight decreases and the mixing ratio of inferior recycled fibers increases, paper break becomes important than ever before. One of the objectives of this study is to analyze paper's physical, mechanical and fracture mechanical properties depending on softwood(SW) and hardwood(HW) mixing ratios and recycling. Fibers were refined by Valley beater to 450 mL CSF. Handsheets of 30 g/$\textrm{m}^2$ were prepared at different mixing ratios. Fracture toughness was measured as the amount of energy applied to cracked sample before total failure. Fracture toughness showed different trend to other strength properties. At the mixing ratio of SW 80: HW 20, papers showed the maximum fracture toughness. At this mixing ratio, flexible softwood fibers were mostly broken and stiff hardwood fibers were mostly pulled out.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.3
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• pp.25-31
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• 2002

The purpose of this study was to analyze how the fiber properties and mixing ratio of softwood and hardwood pulp affect on roundness of printed image. Softwood pulp and hardwood pulp were refined to 400 and 600ml CSF by Valley beater and handsheets of 70 g/$m^2$ basis weight were made at different mixing ratios of hardwood and softwood pulp. The roundness, dot area, and shape of the printed dot were measured by Image Analyzer. The depths and shapes of the acridine orange penetration into paper were measured by CLSM. With higher mixing ratio of hardwood pulp, the paper showed higher air-permeability and better formation, especially at lower freeness. The roundness of the printed image became better and the dot size became smaller when the amount of hardwood pulp increased. Penetration depth of acridine orange by CLSM became greater and roundness increased to real circle when the amount of hardwood pulp increased. It was thought that higher mixing ratio of hardwood fibers resulted in efficient penetration by better formation with uniform micro-pore distribution and it increased roundness. It was thought that fiber properties and mixing ratio affected the structure of paper and the shape of the printed dot. This study showed that the measurement of depth of the liquid penetration into paper without destruction and contact was feasible. Moreover, this method showed that the shape of the liquid penetration was measurable.

• Journal of the Korean Wood Science and Technology
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• v.21 no.1
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• pp.15-20
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• 1993

X-ray diffractograms of the vessel elements and the wood fibers of Quercus variabilis BLUME were recorded and resolved into characteristic reflections of cellulose I. Some differences were observed in the ratio of integrated intensity and crystallinity index between vessel elements and wood fibers. Present results suggest that cellulose crystal structure in the hardwood species was varied with the elements of wood.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.4
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• pp.53-63
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• 1997

Most cellulose resources come from the higher plants, but bacteria also synthesize same cellulose as in plants. Many scientists have been widely studied on the bacterial cellulose, the process development, manufacturing, even marketing of cellulose fibers. The bacterial celluloses are very different in its physical and morphological structures. These fibers have many unique properties that are potentially and commercially beneficial. The fine fibers can produce a smooth paper with enchanced its strength property. But there gave been few reports on the mechanical properties of the processing of bacterial cellulose into structural materials. This study were performed to elucidate the mechanical properties of sheets prepared from bacterial cellulose. Also reinforcing effect of bacterial cellulose on the conventional pulp paper as well as surface structures by scanning electron microscopy were discussed. Paper made from bacterial cellulose is 10 times much stronger than ordinary chemical pulp sheet, and the mixing of bacterial cellulose has a remarkable reinforcing effect on the papers. Mechanical strengthes were increased with the increase of bacterial cellulose content in the sheet. This strength increase corresponds to the increasing water retention value and sheet density with the increase of bacterial cellulose content. Scanning electron micrographs were shown that fine microfibrills of bacterial celluloses covered on the surfaces of hardwood pulp fibers, and enhanced sheet strength by its intimate fiber bonding.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.3
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• pp.47-54
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• 2015

In this study, effects of kneading treatment on the properties of hardwood bleached kraft pulp (HwBKP), softwood bleached kraft pulp (SwBKP) and hardwood bleached chemi-thermo-mechanical pulp (HwBCTMP) were elucidated with a laboratory two-shaft kneader. Kneading treatment was performed at 30% (w/w) of pulp concentration and the number of passes through the kneader was adjusted from 0 to 10 passes. Then, changes in properties of pulp fibers were evaluated. It was found that fiber characteristics were influenced by kneading treatment. Fiber length was decreased with kneading while other morphological properties such as fiber width, curl and kink became increased as the number of passes through the kneader increased from 0 to 5 passes. The magnitude of changes in the morphological properties of softwood chemical pulp was the largest, followed by hardwood chemical pulp. The morphological properties of HwBCTMP were little influenced by kneading treatment. Swelling of fiber measured by WRV was increased with kneading except of HwBCTMP.

• 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.

• Journal of Forest and Environmental Science
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• v.26 no.2
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• pp.75-82
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• 2010

The biometry, morphological properties and chemical composition of bagasse, corn, sunflower, rice, and rapeseed residues plants were analyzed. The results revealed differences in biometry properties and chemical composition of the different types of agricultural resides investigated. The greatest proportion of fiber length (1.32 mm) and cellulose (55.56%) was found in residues of bagasse plants, with a low ash (1.78%) and lignin (20.5%). The lignin of all types of agricultural resides was less than hardwood and softwood. In addition, the rice and rapeseed residues plants had highest amount of ash and extractive component. The slenderness and flexibility ratios of the all types of agricultural resides fibers were similar to some of hardwood and softwood species.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.1
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• pp.57-64
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• 2011

The purpose of this research is to investigate the anatomical and chemical properties of arrowroots for the use of paper fibers. The cells consisting of arrowroots showed certain affinities with those in the fibers and vessels of hardwood. Its parenchyma cells showed different shapes with those of hardwood. It was observed that starch was filled in the multi-shape cells. The average width and length of arrowroot fibers were $15.2{\mu}m$ ($11.1-20.3{\mu}m$) and 1.9 mm (1.49 mm-2.31 mm), respectively. In the chemical characteristics of arrowroots, the contents of cold- and hot-water, alcohol-benzene, and alkali extractives were 12-17%, 15.6%, and 38.8%, respectively. Its chemical composition was 61.3% holocellulose, 15.5% lignin and 2.0% ash.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.1
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• pp.30-37
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• 2001

The effects of enzymatic treatment of recycled fiber were investigated to obtain the basic informations which can be used to improve the papermaking properties of recycled fiber. The recycled fibers were prepared by the repeated handsheet making and disintegrating of hardwood of hardwood and softwood kraft pulp. Novozym 342, Dinimax and Pulpzyme HC were used for enzymatic treatment. The change of fiber length distribution, freeness, contact angle and crystallinity of pulp were measured. The brightness, opacity, breaking and tear index of paper were also measured. The enzymatic treatment decreased long fiber fraction of recycled hardwood fiber, but increased long fiber fraction of recycled softwood fiber. Freeness was decreased with 0.1% enzyme and then increased again with the increase of th enzyme dosage. The improvement of flexibility of recycled fiber was obtained through the decrease of contact angle that is resulted from the decrease of crystallinity of fiber. Brightness and opacity were affected by the type of pulp and enzyme, and dosage of enzyme. Breaking length of recycled hardwood fiber was improved with enzyme treatment, but breaking length of recycled softwood fiber was decreased except for 0.01% Pulpzyme treatment. Tear index was decreased with enzymatic treatment and the lowest decrease was observed with the treatment to Pulpzyme.