• 펄프종이기술
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• 제48권1호
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• pp.43-52
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• 2016

The coniferous fallen leaf is one of the major forestry residues. Since the coniferous fallen leaf would not be easily decayed, the large amount of the coniferous fallen leaves in forestry could be the source of forest fire. The applicability of the fallen leaves to the pulp mold were evaluated for developing new utilization of coniferous fallen leaves. The morphological properties and the chemical composition of the fallen leaves of Pinus densiflora and Pinus koraiensis were evaluated by the comparison with those of fresh leaves. The applicability of the coniferous fallen leaves to the pulp mold and the effects on the pulp mold properties including the scent diffusion were investigated. The fallen leaves showed the shrunk structure by losing the hot water extract component, which leaded to better grinding properties than that of fresh leaves. The pulp mold with fallen leaves showed higher strength properties than the pulp mold with fresh leaves. Although the scent of the pulp mold with fresh leaves was stronger, the pulp mold with fallen leaves had coniferous scent too. The application of fallen leaves to pulp mold for the functional properties could be possible by improving the mechanical properties and the scent lasting treatments.

• 펄프종이기술
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• 제44권5호
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• pp.1-7
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• 2012

Chemical composition, morphological properties and papermaking properties of Sasa quelpaertensis Nakai were investigated in order to use it comprehensively. The lignin contents of stalks and leaves were 18.8% and 15.3% and the holocellulose contents were 63.3% and 48.6% respectively. The contents of ash and the amount of water extract showed the higher value than those of wood or other bamboo species. The average fibers length and width of Sasa quelpaertensis Nakai were 780 ${\mu}m$ and 14.8 ${\mu}m$. The fibers of Sasa quelpaertensis Nakai stalk had thinner width and more slender structure than those of softwood. The handsheet made of Sasa quelpaertensis Nakai alkaline pulp showed higher in tensile strength and bulkier structure than those of handsheet made of soft wood unbleached kraft pulp.

• 펄프종이기술
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• 제31권2호
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• pp.50-57
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• 1999

This study was carried out to compare a conventional alkaline flotation deinking conditions with neutral deinking conditions with and without enzyme addition with respect to the ink removal efficiency and theflotation deinking filtrate quality such as chemical oxygen demand, cationic demand, suspended solids. Based on ink removal rate the neutral deinking condition without enzyme was better than the alkaline deinking condition, and the neutral deinking with enzyme addition turned out to be the best. The brightness of the deinked pulp was found to be the same trend as the ink removal rate. Flotation reject rate for the neutral deinking condition without enzyme was higher than that of the alkaline deinking condition, but that of the neutral deinking condition with enzyme was lower than that of the alkaline and the neutral deinking condition without enzyme. On the freeness of the deinked pulp, the neutral deinking condition with enzyme had the highest value and the alkaline deinking condition had the lowest value among the conditions tested. On the filtrate of the flotation stage, the cationic polymer demand of the neutral deinking condition with enzyme was much lower than the other conditions. Suspended solids and chemical exygen demand for the neutral flotation deinking filtrate was lower than those of the alkaline flotation deinking filtrate.

• 펄프종이기술
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• 제47권4호
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• pp.81-87
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• 2015

Soda-AQ pulp made from sugarcane bagasse (SCB) were bleached in element chlorine free (ECF) sequence. To reduce chlorine dioxide use, final peroxide bleaching was introduced. Prior to peroxide bleaching, different chelating chemicals were applied for comparative analysis in ISO brightness and viscosity. When using equal total chlorine dioxide usage (4.5%), bleached SCB pulp using chelate and hydrogen peroxide (DEDQP) was reached 86.8% (DTPA), 86.4% (EDTA) ISO brightness, whereas bleached pulp using only hydrogen peroxide (DEDP) reached at 81.2% ISO brightness. Viscosity of DEDQP bleached pulp was 25.6 cPs (DTPA), 25.2 cPs (EDTA), And DEDP bleached pulp was shown 18.0 cPs viscosity. Decreasing of transition metal by chelate process led to improvements in final brightness along with higher viscosity. Due to EDTA is 5-7 times cheaper than DTPA, EDTA is recommended as chelating chemical prior to peroxide bleaching.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2010년도 춘계학술발표회 논문집
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• pp.195-206
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• 2010

Xylan can be applied to improve the strength properties of paper; however the optical properties, such as brightness, are decreased significantly. To solve that problem, an applicable bleaching process is therefore desired. The aim of this research was to investigate the impact of hydrogen peroxide bleaching on hardwood kraft pulp pretreated with birchwood xylan by measuring optical properties (whiteness, brightness, opacity) as well as physical properties (tensile index, tearing index, bulk) of handsheets made from the bleached pulp. Hydrogen peroxide bleaching, as a kind of totally chlorine free (TCF) bleaching method, is quite important industrially for chemical pulp. In our work, the process variables of peroxide bleaching including bleaching temperature, time, initial pH and $MgSO_4$ dosage were studied. The results showed that both good mechanical properties and optical properties could be achieved when the operating parameters were controlled properly and therefore hydrogen peroxide bleaching was proved to be a suitable method for bleaching hardwood kraft pulp with adsorption of birchwood xylan.

• 펄프종이기술
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• 제43권3호
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• pp.106-112
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• 2011

The effects of alkaline treatment on the WRV, crystalline structure and sheet structure of softwood and hardwood bleached kraft pulp were investigated. Sodium hydroxide and sodium carbonate were used as chemicals for alkaline treatment and two levels of alkali dosage (5%, 10%) were applied respectively. Alkali treated and untreated pulp were refined to three levels (550, 450 and 350 mL CSF). WRV of the alkali treated pulps depended on the alkaline type and concentration. It was found that the crystalline structures of softwood and hardwood pulp were not changed by refining. Sodium carbonate and lower concentration of sodium hydroxide treatment did not caused any modification of cellulose crystalline structure, while higher concentration of sodium hydroxide treatment caused the partial modification of cellulose crystalline structure. Alkaline treatment of hardwood bleached kraft pulp led to the shrinkage of fiber diameter and bulky structure of sheet. Alkaline treatment of softwood bleached kraft pulp did not cause the significant change in fiber shrinkage and bulk of sheet.

• 펄프종이기술
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• 제37권1호
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• pp.53-60
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• 2005

The mechanical properties of deinked mixed office waste paper in relation to sorts and dosage of enzymes were investigated for successful enzymatic deinking of mixed office waste paper. The increasing of $\Delta$. freeness was most predominant in pulp of Denimax treated pulp. The tensile and burst properties are decreased with enzyme dosage while $\Delta$. freeness were increased. The fine content in disintegrated pulp was decreased with enzyme dosage of $0.4\%$ on the dried weight of paper. The water absorption of handsheets of enzyme deinked pulp was like as that of market roll tissue papers and the mechanical properties of handsheets of enzyme deinked pulp were improved with enzyme treatment comparing of market roll tissue papers.

• 생체재료학회지
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• 제22권4호
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• pp.346-351
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• 2018

Background: Carbonate apatite ($CO_3Ap$) and silica-calcium phosphate composite (SCPC) are bone substitutes with good prospect for dental application. SCPC creates a hydroxyapatite surface layer and stimulate bone cell function while, $CO_3Ap$ induce apatite crystal formation with good adaptation providing good seal between cement and the bone. Together, these materials will add favorable properties as a pulp capping material to stimulate mineral barrier and maintain pulp vitality. The aim of this study is to investigate modification of $CO_3Ap$ cement combined with SCPC, later term as $CO_3Ap-SCPC$ cement (CAS) in means of its chemical (Calcium release) and physical properties (setting time, DTS and pH value). Methods: The study consist of three groups; group 1 (100% calcium hydroxide, group 2 $CO_3Ap$ (60% DCPA: 40% vaterite, and group 3 CAS (60% DCPA: 20% vaterite: 20% SCPC. Distilled water was employed as a solution for group 1, and $0.2mol/L\;Na_3PO_4$ used for group 2 and group 3. Samples were evaluated with respect to important properties for pulp capping application such as pH, setting time, mechanical strength and calcium release evaluation. Results: The fastest setting time was in $CO_3Ap$ cement group without SCPC, while the addition of 20% SCPC slightly increase the pH value but did not improved the cement mechanical strength, however, the mechanical strength of both $CO_3Ap$ groups were significantly higher than calcium hydroxide. All three groups released calcium ions and had alkaline pH. Highest pH level, as well as calcium released level, was in the control group. Conclusion: The CAS cement had good mechanical and acceptable chemical properties for pulp capping application compared to calcium hydroxide as a gold standard. However, improvements and in vivo studies are to be carried out with the further development of this material.

• 펄프종이기술
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• 제41권5호
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• pp.1-7
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• 2009

Oxidized acetate starch was synthesized from corn oxidized starch and vinyl acetate. The sizing concentration and degree of substitution of modified starch on surface strength, smoothness and water resistance of the paper have been studied. The results showed that the surface strength, smoothness and other properties of paper sized by oxidized acetate starch is better than that of oxidized starch. When the degree of substitution of modified starch is from 0.04 to 0.14, the properties of paper sized by oxidized acetate starch have been improved more effectively.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2008년도 추계학술발표논문집
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• pp.1-10
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• 2008