• 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 Society of Clothing and Textiles
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• v.29 no.9_10 s.146
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• pp.1295-1305
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• 2005

The study was based on a three-stage, non-repetitive factorial experiment in which chemical-rotted kenaf fibers were treated separately with hydrogen peroxide concentrations of $0.5\%,\;1\%\;and\;2\%$, with pH solutions of 7, 9 and 11, and treatment times of 30, 60 and 90 minutes. Under optimal conditions, the study was conducted to determine the bleaching efficiency by the addition of chelators, penetrants and surfactants. The bleaching effects on the kenaf fibers were high in high hydrogen peroxide concentration, high in alkali solution pH, low in long treatment time. The optimal level of hydrogen peroxide on bleaching effects were at $2\%$ hydrogen peroxide concentration, with pH of 11 and treatment time of 60 minutes. Under the conditions of $2\%$ hydrogen peroxide concentration, pH 11 and treatment time of 60 minutes, the addition of chelator: Sodim Pyrophosphate(SP), Citric Acid(CA) made the bleaching effects of the kenaf fibers high.

• Textile Coloration and Finishing
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• v.35 no.4
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• pp.206-213
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• 2023

This study attempted to investigate what color would fade more during hair bleaching and examine what should be done to make hair color last longer. For this, hair was colored differently in ash gray with permanent hair dyes and semi-permanent hair dyes each. Hair in multiple levels was created through such bleaching. Color retention was improved in consideration of the degree of color fading in sample hair. In terms of post-bleaching hair coloring, it was more efficient to color hair by eliminating redness without hair damage after shampooing with a permanent hair dye. Therefore, it is anticipated that the study results would be highly useful for beauty salons to find a base level in consideration of bleaching effects and make improve- ments according to hair retention and moisturizing effects.

• Korean Journal of Poultry Science
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• v.34 no.2
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• pp.99-104
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• 2007

Studies were conducted to evaluate spent bleaching clay as a feed resource. Raw spent bleaching clay from the soybean refining process in a rotary reactor is rich in crude fat (26.0%) and crude ash (68.3%) but low in moisture (5.2%) and crude protein (0.5%). The peroxide value of spent bleaching clay was significantly higher than soybean oil (P<0.05). Also the acid value of spent bleaching clay and soybean oil were 9.72 and 0.001, respectively, it was significantly different(P<0.01). It is possible that the acidification of spent bleaching clay was prevented by artificial method. On the feeding experiment, 2.0 to 4.0% of dietary spent bleaching clay were improve body weight gain, feed intake and feed/ gain. Results indicate that spent bleaching clay may be used at 2.0 to 4.0% for broiler diets without deleterious effects on performance.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.20.1-20.14
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• 2020

Objectives: To minimize the tooth sensitivity caused by in-office bleaching, many dentists use non-steroidal anti-inflammatory drugs and topical desensitizing gels containing potassium nitrate and sodium fluoride. This study aimed to evaluate the influence of these substances on inflammation and the expression of substance P and calcitonin gene-related peptide in pulp nerve fibers. Materials and Methods: Seventy-two rats were divided into 6 groups as follows: GI, control; GII, only dental bleaching; GIII, only ibuprofen; GIV, ibuprofen administered 30 minutes before and after the bleaching treatment and every 12 hours until the analysis; GV, only topical application of a desensitizing agent; and GVI, topical application of a desensitizing agent before dental bleaching. Placebo gel was applied to the upper left jaw and the bleaching agent was applied to the upper right jaw in all groups. Subsequently, the groups were divided into 3 subgroups based on the time of analysis: 0, 24, and 48 hours after bleaching (n = 8). The rats were euthanized and the maxillae were processed and evaluated by histopathological and immunohistochemical analyses. The data were analyzed using the Kruskal-Wallis test, followed by the Dunn test (p < 0.05). Results: In the bleaching groups, the inflammatory process and expression of neuropeptides decreased over time. The animals in which a desensitizing agent was applied showed better results within 24 hours. Conclusions: The use of a desensitizing agent had positive effects on inflammation and pain-related neuropeptide expression, minimizing the painful effects of dental bleaching treatment.

• Fashion & Textile Research Journal
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• v.7 no.1
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• pp.96-100
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• 2005

The bleaching is one of the worst factors which leads to the damage of the human hair. The cuticle of the human hair is injured by the alkali that is one of the chief ingredients of a bleaching agent. The alkali component of the bleaching solution chemically reacts with human hair, reducing the tenacity and dissolving the cuticle layer. The purpose of this study is to examine the effects of bleaching time and temperature on the physical properties and morphology. The results were as follows. 1. The stress-strain curves for human hair indicated the three distinct regions, such as Hookean region, Yield region and post-Yield region. The tenacity of hair is reduced gradually with an increase of bleaching time. Under these same conditions, elongation of the hair increased. 2. The greatest drop in tenacity for hair occured between $40^{\circ}C$ and $60^{\circ}C$ of bleaching temperature. 3. Compared with the virgin hair, bleached hair showed a slower rate of weight reduction in the TGA thermogram. The rate decreased gradually as the bleaching time and temperature increased. 4. As the bleaching conditions reached time and temperature extremes, the human hair cuticle became more damaged. The cuticle layers seemed to have dissolved, as seen in the SEM photographs.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.3
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• pp.79-85
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• 2012

In this study, purified cellulose was prepared from rice husk which is one of the major agricultural residues in Korea. The various bleaching processes such as ozone bleaching, $ClO_2$ bleaching and $H_2O_2$ bleaching were applied to remove residual lignin and impurities. In order to increase the contents of ${\alpha}$-cellulose contents, the effects of acid and alkali treatments were evaluated. Although the multi stages of the bleaching processes resulted in less than 0.5 % residual lignin contents, the application of ozone leaded to the decrease in DP(degree in Polymerization) and ${\alpha}$-cellulose contents. The alkali treatment after bleaching processes resulted in pure cellulose which showed more than 98% of ${\alpha}$-cellulose contents.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.1
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• pp.52-61
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• 1997

This study was aimed to decrease AOX(Adsorbed Organic Halide Compounds) by applying bleaching methods of A(HNO$_3$ ＋ NaNO$_2$) and $D^{(H/L)}$(dual pH chlorine dioxide bleaching) to conventional OCEDED bleaching stages. And so we investigate the effects of NSA treatment and the influence of production rate of ion species in chlorine dioxide and pulp mixtures according to various pH as well as dual pH on pulp bleaching. Finally the effects of AOC_DED^{(H/L)}ED^{(H/L)}$ bleaching stage were investigated by measuring AOX, brightness, kappa number and viscosity of pulps. A stage was treated by using 4% $HNO_3$ and 0.05~2.0% $NaNO_2$ on pulp and $D^{(H/L)}$ stage was like that pulp mixed with chlorine dioxide solution was adjusted at pH 7.0 and reacted in pulp cosistency 3%, S~20min, $70^{\circ}C$, and then successively for 160~175min at pH 4.0. It was found that suitable $NaNO_2$ addition rate was at 0.6% where the brigtness of pulp was most higher and pulp viscosity was not decreased much. Chlorate ($CIO_3$) was decreased according to pH increase but chlorite($CIO_2$) was highly decreased according to pH increase. And chloride was slightly increased with pH increase. The applying of A and D^{(H/L)}$ bleaching stages to some various multiple bleaching stages ($AOC_DED^{(H/L)}/EopD^{(H/L)} etc.$) had good results that brightness was increased more 2~3% ISO than conventional method(OCEDEopD), but viscosity was dropped by only 1~2cps.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.7 no.1
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• pp.6-17
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• 1998

Tooth bleaching was being done more than 100 years ago, but the standard for vital tooth bleaching for the last quarter century has been the use of hydrogen peroxide with heat or with a combination of heat and light. The major disadvantages of this process are high cost, unpredictability of results, and patient discomfort. In March, 1989, the dental world was introduced to a new vital tooth bleaching process by Haywood and Heymann in their article "Nightguard vital bleaching(NGVB)." Interestingly enough, this simple technique could have been developed years ago if we had known about the chemical effects of carbamide peroxide on tooth structure. NGVB has created a resurgence in the area of bleaching, primarily because of its relative ease of application, the safety of the materials used, low cost, and the high percentage of successful treatments. This article was to explain simply about all around NGVB(etiology of stains, bleaching chemicals and mechanisms, bleaching effectiveness, side effect, documentation, indications, treatment therapy, laboratory procedure, case reports)

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.1
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• pp.1-10
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• 2014

Xylanase (X) derived from Aurreobasidium pullulans and laccase-mediator system (LM) using Trichophyton sp. LKY-7 laccase (TrL) and N-hydroxy-2-pyridone analogue (NHP) as a mediator were applied in hardwood kraft pulp (HwKP) bleaching. The individual and the synergistic effects of X and LM stage were investigated in the enzymatic bleaching of HwKP. Also, the effects of subsequent alkaline extraction (E) and alkaline/hydrogen peroxide treatment (P) were examined. In X or LM treatment alone, an appreciable bleaching effect of HwKP was not observed, whereas subsequent E or P stage enhanced the increase of brightness and the decrease of kappa number. Especially, P stage significantly enhanced the bleaching effect of pulp. Bleaching of HwKP with XLM sequentially gave significantly higher pulp brightness and lower kappa number than that obtained after the treatment of HwKP with X+LM simultaneously. When HwKP was sequentially treated with XLM followed by P stage, the brightness increased by about 11% ISO and the kappa number decreased by about 3.6 in comparison with the initial pulp. Xylanase and laccase were strongly inactivated by NHP both in the absence and the presence of pulp.