• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.4
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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.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.13-20
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• 2015

Soda-AQ pulp made from sugarcane bagasse (SCB) and oil palm trunk (OPT) were bleached in element chlorine free (ECF) sequence. Bleached SCB and OPT pulp was achieve higher brightness than 85.0% ISO. Viscosity of SCB bleached pulp and OPT bleached pulp were achieved 18-27 cPs and 18-26 cPs. In 7.8% active chlorine dioxide addition, bleached SCB pulp was shown 88.7% ISO brightness and 20.4 cPs viscosity. And bleached OPT pulp was shown 88.5% ISO brightness and 18.8 cPs viscosity with 7.8% active chlorine dioxide addition.

• Fibers and Polymers
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• v.5 no.2
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• pp.128-133
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• 2004

This paper reports the effects of bleaching of alpaca tops and dyeing of bleached alpaca tops/yarns on the quality of tops and yarns. A dark brown alpaca top was bleached with hydrogen peroxide. Two bleaching methods were tried for effectiveness of color removal. A portion of each bleached top was dyed after bleaching. Color parameters were examined for unbleached, bleached and bleached/dyed tops, these tops were then converted into yarns of different twist levels and counts using a worsted spinning system. Some of the bleached yarn from each bleaching method was dyed in a package dye vat to compare the difference of top dyeing versus yarn package dyeing on yarn quality. Fiber diameter, yarn strength, yarn evenness, yarn hairiness and fiber degradation were tested to examine the effects of bleaching and dyeing on these properties at top and yarn stages. A processing route for bleaching and dyeing alpaca fiber was recommended.

• Journal of the Korean Wood Science and Technology
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• v.25 no.2
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• pp.100-109
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• 1997

The objectives of this study was to decrease pollutions of bleaching effluent and was to enhanced brightness of non-chlorine bleached pulps by xylanase treatments. Xylanase cloned Esherichacoli(E. coli) capable of each of endo, exo-xylanase and acetyl-esterase were obtained from Bacillus stearothermophillus. These xylanase was maintained high activity in alkali and high temperature. Especially endo-xylanase would be more active in $60^{\circ}C$ and pH 11. Xylanase pretreatment(X) of unbleached pulp increased brightness, and decreased the degree of delignification. The degree of increase in brightness of pulp due to xylanase pretreatment was similar to non-enzyme treated pulp, regardless of the amount of enzyme added. Therefore, the addition of xylanase of 2 unit was recommended when considering costs of enzyme. The pulp bleached XO sequence had higher brightness and lower Kappa no, than O bleached pulp, while pulp bleached XP sequence had similar brightness and Kappa no. with P bleached pulp. In XOC/D, XOZ and XOP bleaching sequences, brightness and degree of delignification were improved. The C/D and Z stage bleached pulp was good effect on rate of raise in brightness and Kappa no., but P stage bleached pulp had similar level in non-enzyme treated bleaching sequence.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.337-347
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• 2006

Papers made from unbleached and bleached bagasse chemimechanical pulp were chemically modified by acetylation. The effects of irradiation on unbleached and bleached also reduced papers of bagasse chemimechanical pulp before and after acetylation were investigated in this study. Chemimechanical pulp was prepared from bagasse and then bleached with hydrogen peroxide. Unbleached and hydrogen bleached pulps were reduced by Sodium borohydride in different procedures. Paper sheets were prepared from pulps and then acetylated using a technical grade of acetic anhydride. Accelerated photo-aging was run on the samples using fluorescent lamps to verify photo-stability of paper sheets before and after pretreatments. Brightness reversion (as Post-color number) and other optical properties of the paper sheets were measured. Efficient inhibition of photo-yellowing of papers made from bagasse CMP was achieved by acetylation. The acetylated unbleached CMP was noticeably photo-bleached during irradiation. Sodium borohydride reduction followed by acetylation had the same effect as acetylation alone at the same degree of reaction time and reductive treatment did not affect the yellowing rate to any great extent. The pre-reduced, acetylated unbleached papers were, however, not brightened during irradiation. Calculation done by Kubelka-Munk equation showed that reductive treatment had little effect in reducing the photo-yellowing of paper made from CMP pulp; a small stabilization effect was observed in the case of bleached CMP, while unbleached CMP was slightly more prone to discolor in the later phase of photo-reversion. The improved stability towards light may was closely related to the decrease in the phenolic hydroxyl content as a result of blocking by acetyl groups during treatment with acetic anhydride. The results support the hypothesis that phenolic hydroxyl has an important role in the process of photo-reversion of high-yield pulps. The results obtained in this study demonstrate that the acetylation of paper manufactured from peroxide bleached Bagasse CMP significantly retards light-induced discoloration. The inhibition of yellowing is connected with a decrease in the phenolic hydroxyl content of both unbleached and peroxide bleached papers.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.97-98
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• 2001

In Experiment 1, two hundred ten hatched broiler chickens(Ross) were assigned to seven dietary treatments for 5weeks. Each treatment was consisted of 3 replications with 10 birds per replication. Control diet was formulated 22%CP and 3,150kcaIME/kg for starter diet, 19%CP, 3,200kca1ME/kg for finisher diet. Euglena gracilis was added to control diet at the level of 0.25, 0.5, 1.0% and Euglena bleached(DHA enriched) at the level of 0.5, 1.0, 2.0% in the diet. 0 Experiment 2, two hundred fifty hatched broiler chickens(Ross) were assigned to five dietary treatments: T1; control, T2: T1 + Euglena gracilis(DHA enriched)0.5%, T3; T1 + Euglena gracilis(DHA enriched)1.0%, T4: T1 + Euglena bleached(DHA enriched)0.5%,T5: T1 $.$Euglena bleached(DHA enriched)1.0%. In Experiment 1, 2.0% Euglena bleached treatment showed highest DHA level in breast muscle(P<0.05), In Experiment 2, 1.0% Euglena bleached treatment showed highest EPA, Lignoceric acid and DHA level in breast muscle(P<0.05).

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.84-89
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• 1999

Treatment with the enzyme pectinase has been reported to lower the cationic demand of thermomechanical pulp(TMP) bleached with alkaline peroxide in the laboratory. We have extended this discovery to bleached TMP produced industrially, and shown that commercial enzyme preparations can treat pulp within 15 minutes at the at the temperature and pH values prevalent in paper mills. About half of the cationic demand in the bleached pulp can be destroyed by pectinase. Dynamic drainage jar experiments show that the enzyme treatment improves the effectiveness of several cationic polymers to increase retention in the absence of retention aids or with non-ionic polymers, and does not damage the strength properties of the pulp. Pectinase could be easily incorporated into paper machine stock preparation systems to lower the charges of cationic retention aids needed in furnishes containing peroxide-bleached mechanical pulp.

• Applied Microscopy
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• v.38 no.3
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• pp.251-257
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• 2008

Human hair experience tensile forces during combing, bleaching and permanent dyeing processes. We have used rheometer to characterize bleached hair tensile response. Also, we investigated to morphological changes after tensile test of virgin hair and bleached hair using scanning electron microscopy. In tensile test, the tensile strength of virgin hair was $14.66g/cm^2$. They were measured as $12.95g/cm^2$, $12.61g/cm^2$ and $11.43g/cm^2$ for after the first, the second and the third trials of bleaching were done, respectively. Virgin hair had a higher tensile force than bleached hair. Tensile strength got lowered as more bleaching trials were done. In the observation of scanning electron microscopy, the fracture and lift-off of the cuticle outer layer were shown in virgin hair and bleached hair. The bleached hair were more lifted off at the outer cuticle layer than virgin hair. Consequently, chemical damage of bleaching agent caused weakening of the outer cuticle in the hair.

• Korean Journal of Microbiology
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• v.8 no.1
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• pp.1-12
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• 1970

Nucleic acid and protein biosynthese of the glucose-bleached Chlorella cells in relation to the process of the chloroplast reformation were traced, by measuring the changes in the amounts of cell constituents and nuclease activities of the cells during the greening process. The contents of RNA and protein of the glucose-bleached cells decreased significantly, shile the contents of nucleotides and amino acids of the cells increased to compared with those of the control, showing that the biosynthetic activities of RNA and protein of the cells were inhibited severely in the glucose-bleaching process. In the early greening process of the glucose-bleached Chlorella cells the contents of RNA and protein of the cells increased significantly, while the contents of nucleotides nad amino acids of the cells increased to compared with those of the control, showing that the biosynthetic activities of RNA and protein of the cells were inhibited severely in the glucose-bleaching process. In the early greening process of the glucose-bleached Chlorella cells the contents of RNA and protein of the cells increased significantly wihout any increase in the chlorophyll contents showing that the massive biosynthese of RNA and protein proceed prior to the chlorophyll bioynthesis in the cells. The phosphate contents in the DNA fraction of the glucose-bleached cells decreased, but the contents of acid-insoluble polyphosphate increased to compared with those of the control in the early greening porcess, exhibiting that the incorporation of the phosphorus from acid-insoluble polyphosphate into DNA was retarded. In the greening process of the glucose-bleached cells the ribonuclease nad deoxyribonuclease activities of the cells decreased to compared with those of the control, although the initial activities of the both enzymes in the cell were far great compared with the control. Although the initial phosphate contents in the lipid fraction of the glucose-bleached Chlorella cells were more great than the control, the phosphate contents in the lipid fraction of the cells decreased in the early greening process to compared with control, and then increased in the late developmental stages in which massive chlorophyll biosynthesis occured.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.183-196
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• 1998

The purpose of this study was to determine the effect of bleaching technique on the shear bond strength of esthetic restorative materials to bovine enamel. The bleaching agent was used 35% $H_2O_2$(Hi-Lite, Shofu, U.S.A.). Experimental groups were divided into two divisions as group A and B. Experimental A groups for the effect of number of bleaching were as follows ; Group Al : no bleaching Group A2 : bleaching 1 time ( for 5 minutes ) Group A3 : bleaching 3 times ( each for 5 minutes ) Group A4 : bleaching 6 times ( each for 5 minutes ) Group A5 : bleaching 9 times ( each for 5 minutes ) Experimental B groups for the effect of storage period in artificial saliva were as follows ; Group B1 : not stored in artificial saliva after bleaching Group B2 : stored in artificial saliva for 1 day after bleaching Group B3 : stored in artificial saliva for 1 week after bleaching Group B4 : stored in artificial saliva for 2 weeks after bleaching Group B5 : stored in artificial saliva for 4 weeks after bleaching Composite resin and glass ionomer cement were bonded to all specimens, and the shear bond strength between enamel and r~storative material were measured in Instron Universal Testing Machine(Instron, 4467, U.S.A,), Additionally, the bleached enamel specimens were examed after etching with 37.4% $H_3PO_4$ for 1 min under SEM(S-2300, Hitachi Co., Japan) to observe the effect of bleaching procedure on enamel surface morphology. The result were as follows ; 1. In SEM findings, bleached bovine enamel was found to be superficially rough. 2. In bleached bovine enamel, the effect of acid etching was reduced with the increase of number of bleaching. 3. The mean shear bond strength of composite resin and glass ionomer cement to bleached enamel surface tended to be lower than those to non-bleached enamel surface. 4. With the increase of number of bleaching, the shear bond strength of composite resin and glass ionomer cement to bleached enamel were progressively decreased. 5. Increasing the, storage period in artificial saliva after bleaching, the shear bond strength of composite resin and glass ionomer cement to bleached enamel were progressively increased. 6. The mean shear bond strength of glass ionomer cement to bleached bovine enamel tended to be clearly lower than that of composite resin.