• Title/Summary/Keyword: Diphenyl ether

Search Result 82, Processing Time 0.03 seconds

Thermal Properties and Water Sorption Behaviors of Epoxy and Bismaleimide Composites

  • Seo, Jong-Chul;Jang, Won-Bong;Han, Hak-Soo
    • Macromolecular Research
    • /
    • v.15 no.1
    • /
    • pp.10-16
    • /
    • 2007
  • In this work, we prepared epoxy/BMI composites by using N,N'-bismaleimide-4,4'-diphenylmethane (BMI), epoxy resin (diglycidyl ether of bisphenol-A (DGEBA)), and 4,4'-diamino diphenyl methane (DDM). The thermal properties and water sorption behaviors of the epoxy and BMI composites were investigated. For the epoxy/BMI composites, the glass transition and decomposition temperatures both increased with increasing BMI addition, which indicates the effect of BMI addition on improved thermal stability. The water sorption behaviors were gravi-metrically measured as a function of humidity, temperature, and composition. The diffusion coefficient and water uptake decreased and the activation energy for water diffusion increased with increasing BMI content, indicating that the water sorption in epoxy resin, which causes reliability problems in electronic devices, can be diminished by BMI addition. The water sorption behaviors in the epoxy/BMI composites were interpreted in terms of their chemical and morphological structures.

Purification and Characterization of Bacillus subtilis Protoporphyrinogen Oxidase and Pre-equilibrium Behavior During Oxidation of Protoporphyrinogen IX

  • Jeong, Eun-Ju;Han, Ok-Soo
    • BMB Reports
    • /
    • v.34 no.1
    • /
    • pp.39-42
    • /
    • 2001
  • Previous studies indicate that B. subtilis protoporphyrinogen oxidase is poorly inhibited by diphenyl ether herbicides. To better understand the basis of this insensitivity, the enzyme was overexpressed as a soluble protein in E. coli, purified and characterized. The mechanism of oxidation of B. subtilis protoporphyrinogen IX was studied and the enzyme kinetic parameters were determined for protoporpyrinogen IX; $K_m$, and $k_{cat}$ were $6.3\;{\mu}M$ and $0.028\;h-^1$, respectively. The enzyme required flavin adenine dinucleotide as a cofactor and its activity was enhanced by 1 mM n-octylglucopyranoside. The nonenzymatic oxidation rate was dependent on the concentration of protoporphyrinogen IX, suggesting that the reaction involves a pre-equilibrium step followed by a rate-limiting step.

  • PDF

Dyeing of Cotton Knitted Fabrics using Mud (머드를 이용한 면 편성물 염색성)

  • 신인수;유복선
    • Korean Journal of Human Ecology
    • /
    • v.5 no.2
    • /
    • pp.93-99
    • /
    • 2002
  • In this paper, the effect of the mud of an inorganic substance dyed on cotton knitted fabrics have been studied. The structure and chemical composition of mud was analyzed. And the far-infrared emissivity and emission power, colorfastness, anti-bacterial properties cotton knitted fabrics dyed with mud were also evaluated. The structure and chemical composition of mud was almost identical structure and to be alike main components were SiO2, A1203 and Fe203. The cotton knitted fabrics dyed with mud have good components and anti-bacterial properties. when the dyed fabrics was after-treated with diphenyl ether, the anti-bacterial property were improved. Far-infrared emissivity and emission fewer cotton knitted fabrics dyed with mud have very good.

  • PDF

Antioxidant and Hepatoprotective Effects of Amomum Xanthoides

  • Wang, Jing-Hua;Shin, Jang-Woo;Son, Chang-Gue
    • The Journal of Korean Medicine
    • /
    • v.31 no.3
    • /
    • pp.98-106
    • /
    • 2010
  • Objective: To examine the in vitro antioxidant and hepatoprotective properties of Amomum xanthoides extract and its fractions. Methods: Methanol extract of Amomum xanthoides was fractionated into three fractions; petroleum ether fraction (PFAX), water fraction (WFAX) and ethyl acetate fraction (AFAX). The antioxidant and hepatoprotective effects of these fractions were compared by in vitro experiments. Results: The total phenols content and DPPH (1 1-Diphenyl-2-picrylhydrazyl) radical scavenging activity was found significant in AFAX when compared with other fractions (PFAX, WFAX). AFAX significantly inhibited NO production by RAW 264.7 cells in LPS-activated condition. In Hep $G_2$ cells, AFAX markedly prevented the leakage of LDH and release of AST against CCl4 challenge. Conclusion: Amomum xanthoides and especially ethyl acetate fraction have potent antioxidative and hepatoprotective properties.

Preparation and dielectric properties of polyimide thin films by vapor deposition polymerization method (진공증착중합에 의한 Polyimide 박막의 제조와 유전특성)

  • 이덕출;김형권
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.45 no.3
    • /
    • pp.380-385
    • /
    • 1996
  • Thin films of polyamic acid(PAA) were fabricated by vapor deposition polymerization(VDP) from pyromellitic dianhydride(PMDA) and 4,4'-diamino diphenyl ether(DDE). Thin films of polyimide(PI) were obtained by curing PAA, and their dielectric properties have been measured. The uniform thin films of PI formed by curing PAA at 300 .deg. C for 1 hr. which was confirmed by Fourier transform Infrared spectroscopy(FT-IR) absorption at 720, 1380, 1780c $m_{-1}$. Relative permittivity and tan .delta. were 3.9 and 0.008 at 10kHz, respectively. (author). 8 refs., 11 figs., 1 tab.1 tab.

  • PDF

Quantitative Extraction Analysis of Brominated Flame Retardant Substances Using Supercritical-Fluid Method for Environmental Assessment (초임계추출법을 이용한 브롬계 난연제 화합물 환경성 평가 추출효율 분석 연구)

  • Oh, Min-Kyung;Yoon, Sang-Hwa;Lee, Young-Kwan;Han, Jae-Sung;Won, Sung-Ho;Nam, Jae-Do
    • Polymer(Korea)
    • /
    • v.32 no.1
    • /
    • pp.13-18
    • /
    • 2008
  • For the evaluation of brominated flame retardants included in polymeric electronic devices, we investigated the extraction methods and solvent systems for four different types of polymers of PC (polycarbonate), PP (polyropylene), PET (poly(ethylene terephthalate)) and PBT (poly(butylene terephthalate)) using different solvent systems of hexane/acetone, THF, toluene, and THF/toluene. In order to compare the extraction efficiency of different methods and solvent systems, the deca-BDE (decabromo diphenyl ether) flame retardant was included in PC, PP, PET and PBT systems and subsequently extracted by soxhlet, ultrasonic, accelerated solvent, microwave and supercritical fluid extraction methods. The amount of the extracted flame retardant was monitored to evaluate the extraction efficiency. The ultrasonic extraction method was found not to be acceptable as an extraction method for the polymer systems mainly due to a low salvation efficiency of the organic solvents. Soxhlet, accelerated solvent and microwave extraction methods exhibited over 80% of extraction efficiency for toluene. The supercritical fluid extraction method, which has been used as an extraction method for flame retardants in polymers, showed the extraction efficiencies of ca. 100% for PC and PP in the optimal extraction conditions of $60^{\circ}C$ and 120 bar.

Synthesis of Some New 4,5-dihydro-6-(4-methoxy-3-methylphenyl)-3(2H)-pyridazinone Derivatives (4,5-Dihydro-6-(4-methoxy-3-methylphenyl)-3(2H)-pyridazinone계 화합물의 합성 연구)

  • Soliman, Mohamed H. A.;El-Sakka, Sahar S.
    • Journal of the Korean Chemical Society
    • /
    • v.55 no.2
    • /
    • pp.230-234
    • /
    • 2011
  • The present study describes the synthesis of 4,5-dihydro-6-(4-methoxy-3-methylphenyl)-3(2H)-pyridazinone derivatives. The synthesis of the first target compound, 4,5-dihydro-6-(4-methoxy-3-methylphenyl)-3(2H)-pyridazinone (1), was achieved by Friedel-Crafts acylation of o-cresyl methyl ether with succinic anhydride and subsequent cyclization of the intermediary g-keto acid with hydrazine hydrate. Condensation of compound 1 with aromatic aldehydes in the presence of sodium ethoxide affords the corresponding 4-substituted benzyl pyridazinones (3a-d). The dihydropyridazinone 1 underwent dehydrogenation upon treatment with bromine/acetic acid mixture to give (4). Pyridazine (5) has been synthesized upon the reaction of pyridazinone (1) with 1,3-diphenyl-2-propen-1-one under the Michael addition reaction. N-dialkylaminomethyl derivatives 6a-b have been obtained from the reaction of pyridazinone 1 with formaldehyde and secondary amine, whereas reaction of 1 with formaldehyde gives N-hydroxymethyl derivative (7). This study also includes the synthesis of the 3-chloropyridazine derivative 8 in excellent yield by heating pyridazinone 3b in phosphorus oxychloride. The behaviour of the chloro derivative toward sodium azide, benzyl amine and anthranilic acid was also studied. The proposed structures of the products were confirmed by elemental analysis, spectral data and chemical evidence.

Synthesis and Curing Behaviors of Polyisoimide Oligomers with Ethynyl End Groups (Ethynyl 말단기를 갖는 Polyisoimide 올리고머의 합성 및 이들의 경화거동에 관한 연구)

  • Choi, Seok Woo;Kim, Bo Ock;Kim, Ji-Heung;Nam, Sung Woo;Jeon, Boong Soo;Kim, Young Jun
    • Polymer(Korea)
    • /
    • v.38 no.6
    • /
    • pp.774-781
    • /
    • 2014
  • Acetylenic or phenylethynyl end-capped polyisoimide oligomers ($M_w$ 2500 g/mol, 5000 g/mol) based upon 4,4'-diamino diphenyl ether (4,4'-ODA)/4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-ODA/3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) were synthesized by using 4-ethynylaniline (4-EA) or 4-phenylethynyl phthalic anhydride (4-PEPA) as an end capper. The incorporation of ethynyl groups were confirmed by FTIR spectroscopy. The isomerization temperature was influenced by molecular weight as well as the backbone structure of polyisoimides oligomers. Thus, polyisoimide oligomers with molecular weight of 2500 g/mol was found to be imidized at temperature $10^{\circ}C$ lower than that for the oligomers with molecular weight of 5000 g/mol. The crosslinking reaction of ethynyl groups occurred at a higher temperature than that for the isoimide/imide isomerization reaction. These two reactions were totally or partially overlapped on the DSC thermograms for the polyisoimide oligomer end-capped with 4-EA. Kinetics of thermal imidization and crosslinking reactions for the 4,4'-ODA/ODPA polyisoimide oligomers end-capped with 4-PEPA were investigated by performing dynamic DSC experiments at heating rate of $10^{\circ}C/min$. The activation energy and pre-exponential factors were 141 kJ/mol and $1.45{\times}10^{13}min^{-1}$ for the imidization reaction and 177 kJ/mol and $2.90{\times}10^{13}min^{-1}$ for the crosslinking reaction, respectively.

Spatial Distribution and Residual Consistency Assessment of PBDEs in the Surface Sediment of the Masan Bay (마산만 표층퇴적물 내의 폴리브롬화디페닐에테르(PBDEs)의 공간적 분포 및 오염도평가)

  • We, Sung-Ug;Yoon, Cho-Hee;Min, Byung-Yoon
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.32 no.5
    • /
    • pp.427-436
    • /
    • 2010
  • A total of 18 surface sediments within the special conservation zone in the Masan Bay were analyzed to investigate the spatial distribution and polluted pathway of polybrominated diphenyl ehters(PBDEs). Twenty-two PBDE congeners were detected and brominated diphenyl ether-209 (BDE-209) among them was predominant. The concentrations of BDE-209 and ${\Sigma}_{21}$PBDEs (sum of 21 PBDE congeners without BDE-209) ranged from 2.32 to 64.2 ng/g and from 0.72 to 8.24 ng/g, respectively. The spatial distribution of both BDE-209 and ${\Sigma}_{21}$PBDEs showed a negative gradient from the inner to the outer Bay, indicating that the source of PBDEs might be mainly located inside the Bay such as streams and an effluent of wastewater treatment plants. It was seemed likely that the major parameters determining levels of PBDEs in the Masan Bay were the distance discharging from their sources as well as the characteristics and movement of sediments due to the flow of sea water.

Herbicidal Phytotoxicity of Early Rice Seedlings as Affected by Cultural Practices - I. Screening of Promising Herbicides (재배조건(栽培條件)의 차이(差異)가 수도(水稻)어린묘(苗)의 제초제(除草劑) 약해발생(藥害發生)에 미치는 영향(影響) - I. 유망제초제(有望除草劑) 선발(選拔))

  • Han, S.U.;Guh, J.O.;Chon, S.U.
    • Korean Journal of Weed Science
    • /
    • v.10 no.4
    • /
    • pp.255-260
    • /
    • 1990
  • Seventeen different herbicides were screened to select promising ones for the control of weeds, which may be used in paddy fields transplanted with 8 days old young rice seedlings. Four classes of herbicides were chosen and tested with seedlings grown under different cultivating conditions. Contact herbicides such as diphenyl-ether and oxadiazol showed severe growth retardation of rice seedlings. Carbamate class(dimepiperate), quinoline class (quinclorac), pyrazol class(pyrazolate), acid amide class(mefenacet and pretilachlor), addition of safener (pretilachlor+fenclorim and mefenacet+bensulfuron+dymuron) and unknown class (KC-7079) exhibited normal growth of seedlings. Sulfonyl urea herbicide class(cimosulfuron, bensulfuron, pyrazosulfuron), and oxarane class(tridiphane) showed the slight growth inhibition but recovered shortly.

  • PDF