• Title/Summary/Keyword: Cresol Red

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The Intumescent Flame Retardant Mechanism of Red-phosphorus Containing Ortho-Cresol Novolac / Biphenyl Epoxy Composites (적인을 포함한 Ortho-Cresol Novolac/Biphenyl 에폭시 복합재료의 발포성 난연 기구)

  • 김윤진;강신우;유제홍;김익흠;서광석
    • Polymer(Korea)
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    • v.26 no.5
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    • pp.623-633
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    • 2002
  • The flame retardant and thermal properties of ortho-cresol novolac (OCN) and biphenyl epoxy blends containing red-phosphorus were investigated. For five types of compounds designed with the volume ratio of OCN and biphenyl epoxy, thermal properties were analysed by TGA or DTC, and flame retardancy effectiveness was estimated through UL-94V test. While the flame retardant and thermal properties were improved with the content of filler and red-phosphorus, the excessive amount of red-phosphorus caused to deteriorate those properties. Using the blends of OCN/biphenyl rather than pure OCN or biphenyl epoxy as a matrix the flame retardancy of composites could be improved by the synergic effects of high thermal resistance of OCN and intumescent property of biphenyl. The flame retardant me chanism of epoxy compound containing red-phosphorus could be thought of the heat-insulating effect of intumescent char-layer formed in the surface of composites.

Study on Optical Characteristics of pH Indicators in the Immobilized Film for Fiber-Optic pH Sensor (광학적 pH 센서를 위한 지시염료가 고정된 필름의 광학적 특성 연구)

  • Kim, Beom Kyu;Park, Byung Gi
    • Journal of Sensor Science and Technology
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    • v.26 no.6
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    • pp.414-419
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    • 2017
  • The optical characteristics of cresol red, phenol red, and neutral red immobilized in the thin film were investigated with absorbance measurement in order to find a sensing part of a fiber-optic pH sensor. Sol-Gel method with tetramethyl orthosilicate as a precursor was used to immobilize the pH indicators in the thin film. The absorbance spectra were measured when pH indicators were immobilized in the film and were dissolved in the buffer solution. Experimental results showed that the absorbance spectra could be changed when the pH indicator is immobilized in the thin film. As compared with other pH indicators, the neutral red exhibited similar absorbance spectra regardless of physical conditions and was sensitive over whole pH range between 4 and 11. In addition, the absorbance ratio of base peak to acid peak tended to increase in proportion to the increase in pH. Experimental results indicate that the neutral red is a good pH indicator for fabrication of a sensing part of the fiber-optic pH sensor.

Hydrocarbon Synthesis of Waste Lignocellulosics by Liquefaction Reaction of Thermochemical Deoxyhdrogenolysis Method (II) (목질폐재(木質廢材)의 열(熱)-화학적(化學的) 탈(脫)산소-수소첨가반응(환원반응)에 의한 액화(液化)탄화수소의 합성 (II))

  • Lee, Byung-Guen
    • Journal of the Korean Wood Science and Technology
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    • v.19 no.4
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    • pp.80-84
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    • 1991
  • Lignocellulosic biomass including acetosolv ricestraw and spruce lignin were liquefied and converted into liquid hydrocarbons by catalytic hydroliquefaction reaction. These experimental works were carried out in 1-liter-capacity autoclave using 50% tetralin and m-cresol solution respectively as soluble solvent and Ni. Pd. Fe and red mud as catalyst. $H_2$ gas was supplied into the reactor for escaltion of deoxhydroenolysis reaction. Catalyst concentrations were 1 % of raw material based on weight. The ratio between raw materials and soluble solvent are 1g and 10cc. The reaction conditions are 400-$700^{\circ}C$ of reaction temperature, 10-50 atms of reaction pressure. The highest yield of hydrocarbon, so called "product oil" showed 32% and 5.5% of lowest char formation when red mud was used as catalyst. The product oil yields from those of other catalysts were in the range of 20-29%. The influence of different initial hydrogen pressures was examined in the range d 30-50 atms. A minimum pressure of 35 atms was necessary to obtain a complete recovery of souble solvent for recycling.

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Structural Characteristics of Nylon 6 Grafted with Polyacrylamide (아크릴아미드로 그라프트 공중합시킨 나일론6의 구조적 특성)

  • Lee, Yang Hun;Park, Chan Hun;Shin, Eun Joo;Choi, Suk Chul
    • Textile Coloration and Finishing
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    • v.9 no.1
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    • pp.1-14
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    • 1997
  • Nylon 6 grafted with polyacrylamide(PAAm) was synthesized by a dispersion polymerization method at 6$0^{\circ}C$ for 2 hours, and a cresol-soluble graft polymer(CSGP) and water-dispersable graft polymer (WI)GP) were separated. Infra-red(IR) spectrum analysis, differential scanning calorimetery(DSC), thermogravimetery(TG), and X-ray diffraction analysis were carried out to research their structural characteristics.

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The Dual-frequency (20/40 kHz) Ultrasound Assisted Photocatalysis with the Active Carbon Fiber-loaded Fe3+-TiO2 as Photocatalyst for Degradation of Organic Dye

  • Xiong, Shaofeng;Yin, Zhoulan;Zhou, Yuanjin;Peng, Xianzhong;Yan, Wenbin;Liu, Zhixiong;Zhang, Xiangyu
    • Bulletin of the Korean Chemical Society
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    • v.34 no.10
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    • pp.3039-3045
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    • 2013
  • Dual-frequency ultrasound assisted photocatalysis (DUAP) method was proposed to degrade a stable organic model effluent, cresol red (CR), using the prepared $Fe^{3+}$-doped $TiO_2$ with active carbon fiber loading ($Fe^{3+}-TiO_2/ACF$) as photocatalyst. The influence of key factors, including Fe doping amount and power density of dual-frequency ultrasounds (20/40 kHz), on the degradation efficiency was investigated. The degradation efficiency rises to 98.7% in 60 min accompanied by the color removal of CR liquid samples from yellow to colorless transparent at optimal conditions. A synergy index of 1.40 was yielded by comparison with single ultrasound assisted photocatalysis (SUAP) and the photocatalysis without ultrasound assisted (UV/$TiO_2$), indicating that a clear synergistic effect exists for the DUAP process. Obvious enhancement of degradation efficiency for the DUAP process should be attributed to production of large amount of free radicals by strong cavitational effects of dual ultrasounds.

PHENOLOXIDASE AND ANTIOXIDANT IN KOREAN GINSENG (고려인삼에 있어서의 페놀 산화효소의 항산화물질)

  • Park E.Y.;Luh B.S.;Branen A.L.
    • Proceedings of the Ginseng society Conference
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    • 1984.09a
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    • pp.257-275
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    • 1984
  • Enzymatic browning is considered desirable in tea and tobacco processing but undesirable in many fruits processing at the present time. It is necessary to understand the nature of the enzyme, phenoloxidase, in order to control browning reactions, and extend its effects to formation of browning products as antioxidants in ginseng. Ginseng exhibits antioxidant activity when incorporated with turkey dark meat patties. The activity in red ginseng showed about two times stronger than white ginseng. One of the phenolic antioxidants from fresh, white and reprocessed white ginseng was identified as phenol 2.6 Bis(1.1 dimethyl ethyl) 4-methyl among several unknown compounds by GC/mass spectrometer. In red ginseng, no phenol 2.6 Bis (1.1 dimethyl ethyl) 4-methyl was detected, the compound may be polymerized by phenoloxidase and form some higher molecular compounds which may possess high antioxidant activity. Phenoloxidase isozymes in fresh Korean ginseng (panax ginseng C.A. Meyer) were extracted with phosphate buffer at pH 7.3. The isozymes were purified through ammonium sulfate fractionation, dialysis and chromatography on a DEAE-cellulose column. Two groups of phenoloxidase were shown to be present, one in the floating agglomerated group and the other in the precipitate. group from the 0.85 saturation ammonium sulfate. The DEAE-cellulose column chromatography, the phenoloxidase isozyme present in the precipitate appears as the first peak (I), and that in the agglomerate in the second peak (II). Isozyme I showed higher activity with catechin and catechal, and isozyme II showed higher activity with p-cresol. The isozyme showed two optimum pH activity one at pH 4.5 and the other at 8.5 with catechin as substrate. Korean ginseng phenoloxidase has high heat stability. When heated at $75^{\circ}C$ for 2 hours, its activity remained $90\%\;and\;80\%$ on phenoloxidase I and II respectively. Phenoloxidase I was most active on (+) catechin followed by p-cresal, catechol and epicatechin. Phenoloxidase II was most active on p-cresal followed by (+) catechin, catechol, p-coumanic acid and epicatechin. Sodium bisulfite, sodium cyanide, ascorbic acid glutachion in the oxidized form, sodium diethyl dithiocarbomate and ethylendiamine tetra acetate (EDTA) acted as inhibitors. Red ginseng color development was initiated by phenoloxidase and finished by a followed sun drying process. The antiaging activity of ginseng may be initiated by the antioxidant in the ginseng.

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Development of Reflection-type Fiber-optic pH Sensor Using Sol-gel Film (졸-겔 필름을 이용한 반사형 광섬유 pH 센서의 개발)

  • Yoo, Wook-Jae;Seo, Jeong-Ki;Jang, Kyoung-Won;Moon, Jin-Soo;Han, Ki-Tek;Park, Jang-Yeon;Lee, Bong-Soo;Cho, Seung-Hyun;Heo, Ji-Yeon;Park, Byung-Gi
    • Journal of Sensor Science and Technology
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    • v.20 no.4
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    • pp.266-271
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    • 2011
  • A reflection-type fiber-optic pH sensor, which is composed of a pH sol-gel film, plastic optical fibers, a mirror, a light source and a spectrometer, is developed in this study. As pH indicators, a bromthymol blue, a cresol red and a thymol blue are used, and they are immobilized in the sol-gel films. The emitted light from a light source is guided by a fiber-optic Y-coupler and plastic optical fibers to the pH sol-gel film in a pH sensing probe. The pH change in the sensing probe gives rise to a change in the color of the pH sol-gel film, and the optical characteristic of reflected light through the pH sol-gel film is also changed. Therefore, we have measured the spectra of reflected lights, which are changed according to the color variations of the pH sol-gel films with different pH values, by using of a spectrometer. Also, the relationships between the pH values and the intensities of reflected lights are obtained on the basis of the color variations of the pH sol-gel films.