• Fibers and Polymers
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• 제5권2호
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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.

• 한국의류학회지
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• 제29권9_10호
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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.

• 한국염색가공학회지
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• 제35권4호
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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.

• 한국가금학회지
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• 제34권2호
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• pp.99-104
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• 2007

본 연구는 식용유 정제 폐백토(spent bleaching clay)를 육계 사료 원료로 가치를 평가하기 위해서 실시하였다. 식용유 정제 폐백토(spent bleaching clay)는 대두유의 정제 과정에서 생산되어지며, 생 식용유 정제 폐백토(spent bleaching clay)속에는 조지방(26.0%)과 조회분(68.3%)은 풍부하나, 수분(5.2%)과 조단백질(0.5%)의 함량은 낮게 평가되었다. 식용유 정제 폐백토(spent bleaching clay)와 대두유의 산가는 각각 9.72 및 0.001로 유의한 차이가 인정되었다(P<0.05). 뿐만아니라 식용유 정제 폐백토(spent bleaching clay)의 과산화물가는 대두유보다 유의하게 높아서(P<0.05) 식용유 정제 폐백토(spent bleaching clay)의 빠른 산패 가능성을 시사한 결과이다. 그러나 식용유 정제 폐백토(spent bleaching clay)의 산패는 인공적인 방법으로 막을 수 있을 것이다. 한편 식용유 정제 폐백토(spent bleaching clay)의 육계 사육에서의 $2.0{\sim}4.0%$의 첨가는 사료 섭취량, 증체량 및 사료 효율을 개선시켰다. 결론적으로 육계 사료에 $2.0{\sim}4.0%$의 식용유 정제 폐백토(spent bleaching clay)의 이용이 가능할 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제45권2호
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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.

• 한국의류산업학회지
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• 제7권1호
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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.

• 펄프종이기술
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• 제44권3호
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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.

• 펄프종이기술
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• 제29권1호
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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.

• 대한심미치과학회지
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• 제7권1호
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• pp.6-17
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• 1998

치아미백은 100여년전 이상부터 시행되어 왔으나, 지난 4반세기 동안의 생활치아 미백술의 표준적인 방법은 과산화수소와 열원을 사용하거나, 열원과 광원을 복합해서 사용하는 것이었다. 이 술식의 단점은 술식의 복잡성, 많은 비용, 결과의 불확실성과 환자의 불편이었다. 1989년 3월에 치과계에서는 Haywood와 Heyman에 의해 발표된 새로운 생활치아 미백술(Night Guard Vital Bleaching)을 도입했다. 치아구조에 대한 carbamide peroxide의 화학적 효과를 알고 있었으면 수년 전에 개발되었을 아주 간단한 치료술식이다. 이 방법은 시술이 쉽고, 사용 되는 재료의 높은 안전성, 낮은 치료비, 높은 성공률로 최근 다시 치아미백 붐을 일으키는데 일조를 하고 있으며, 생활치아 미백술의 표준적인 방법으로 신속히 자리잡아가고 있다.

• 펄프종이기술
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• 제46권1호
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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.