• Title/Summary/Keyword: 1,3-Butadiene

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Effect of Binder and Electrolyte on Electrochemical Performance of Si/CNT/C Anode Composite in Lithium-ion Battery (리튬이온 이차전지에서 Si/CNT/C 음극 복합소재의 전기화학적 성능에 대한 바인더 및 전해액의 효과)

  • Choi, Na Hyun;Kim, Eun Bi;Yeom, Tae Ho;Lee, Jong Dae
    • Korean Chemical Engineering Research
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    • v.60 no.3
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    • pp.327-333
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    • 2022
  • In this study, silicon/carbon nanotube/carbon (Si/CNT/C) composites for anode were prepared to improve the volume expansion of silicon used as a high-capacity anode material. Si/CNT were prepared by electrostatic attraction of the positively charged Si and negatively charged CNT and then hydrothermal synthesis was performed to obtain the spherical Si/CNT/C composites. Poly(vinylidene fluoride) (PVDF), polyacrylic acid (PAA), and styrene butadiene rubber (SBR) were used as binders for electrode preparation, and coin cell was assembled using 1.0 M LiPF6 (EC:DMC:EMC = 1:1:1 vol%) electrolyte and fluoroethylene carbonate (FEC) additive. The physical properties of Si/CNT/C anode materials were analyzed using SEM, EDS, XRD and TGA, and the electrochemical performances of lithium-ion batteries were investigated by charge-discharge cycle, rate performance, dQ/dV and electrochemical impedance spectroscopy tests. Also, it was confirmed that both capacity and rate performance were significantly improved using the PAA/SBR binder and 10 wt% FEC-added electrolyte. It is found that Si/CNT/C have the reversible capacity of 914 mAh/g, the capacity retention ratio of 83% during 50 cycles and the rate performance of 70% in 2 C/0.1 C.

A Novel Photoreaction of (2-Hydroxyethoxyphenyl)pentamethyldisilane

  • Park, Seung Ki;Seong, Won-Je
    • Bulletin of the Korean Chemical Society
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    • v.30 no.6
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    • pp.1331-1336
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    • 2009
  • Photolysis of (2-hydroxyethoxyphenyl)pentamethyldisilane 2 in benzene provides a novel intramolecular cyclization photoproduct 9 which was probably formed from the intramolecular reaction to form a seven-membered ring in silatriene intermediate 7 and then the photochemical disrotatory ring closure of 1,3-butadiene moiety to cyclobutene. Irradiation of 2 in methanol afforded photoproducts 5 and 6 which were formed by the nucleophilic attack of methanol to $\beta$ or $\alpha$ silicon atom in pentamethyldisilanyl group of the photoexcited state of 2. Compounds 10 and 11 were also formed by the same way as in the formation of the photoproducts 5 and 6 in the photolysis of (2-allyloxyethoxyphenyl)pentamethyldisilane 3 in methanol solvent. Photoreaction of (2-acetoxyethoxyphenyl) pentamethyldisilane 4 in methanol gave a photoproduct 12 which was formed via the elimination of dimethylsilylene species in the photoexcited state of 4.

Dependence of Thermal and Electrochemical Properties of ceramic Coated Separators on the Ceramic Particle Size (알루미나 크기에 따른 세라믹 코팅 분리막의 열적 특성 및 전기화학적 특성)

  • Park, Sun Min;Yu, Ho Jun;Kim, Kwang Hyun;Kang, Yun Chan;Cho, Won Il
    • Journal of the Korean Electrochemical Society
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    • v.20 no.2
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    • pp.27-33
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    • 2017
  • Conventional lithium ion batteries suffer from notorious safety issues caused by inevitable lithium dendrite formation and proliferation during over/fast charging processes. The lithium dendrites or mechanical damage on the separator induce internal short circuit in LiB that generates extensive amount of heat within contacted electrode surfaces through the separator. During this heat generation, conventional polyolefin separators shrinks dramatically, and increasing short circuit pathway, that causes the battery to explode. To overcome this serious issue, ceramic coated separators are developed in commercial LiB to enhance thermal and mechanical stability. In this paper, various size(IL = 488.5 nm, I = 538.7 nm, S = 810.3 nm, D = 1533.3 nm) of $Al_2O_3$ particles are coated using styrene-butadiene rubber(SBR) / carboxymethyl cellulose(CMC) binder on PE separator to investigate its thermal stability and electrochemical effect on LiB coin cell with NCM cathode and Li metal anode.

Management of Cancer Risk Caused by Motor Vehicle in a Large City (대도시 자동차 배출가스의 발암위해 관리 방안)

  • 김강석
    • Environmental Analysis Health and Toxicology
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    • v.13 no.1_2
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    • pp.27-31
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    • 1998
  • Motor vehicle exhaust is the major cause to the air contamination in Seoul. It includes many toxic chemicals to human health such as aidehyde, PAHs, benzene, xylene, toluene, benzo[a]pyrene, nickel, arsenic and cadmium in gasoline exhaust and formaldehyde, PAHs, 1,3-butadiene, benzene and particulate matter in diesel exhaust. Some chemicals out of them are classified as a human carcinogen. Many large diesel vehicles such as buses and trucks are drivened frequently in Seoul so that the air in Seoul is seriously contaminated by diesel exhaust, especially particulate matter. The amounts of particulate matter from large diesel vehicles may be estimated to be more than 50% of small dust in Seoul. The particles of particulate matter are coated with many toxic chemicals and some of these are considered as a human carcinogen. The cancer risk has to be throughly managed because the population density of Seoul is very high. Government should list hazardous air pollutants in Seoul, assess the exposure of people to toxic pollutants, especially carcinogens and manage human health risk.

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Studies on the Physical Properties and Application of EPDM-Polymer Blends. Part 4. Physical Properties for EPDM-NBR Blends (EPDM과 각종(各種)Polymer의 Blend에 의(依)한 성능변화(性能變化) 및 그 응용(應用)에 관(關)한 연구(硏究)(제4보(第4報)) EPDM과 Acrylonitrile-Butadiene Rubber의 Blend에 대(對)하여)

  • Kim, Joon-Soo
    • Elastomers and Composites
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    • v.7 no.1
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    • pp.45-52
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    • 1972
  • As a series of the studies of EPDM-Polymer blends, the experiments are concentracted to the investigation of the physical properties of the EPDM-NBR blends. The results are shown as follows; 1. As EPDM addition ratio is increased, the physical properties such as resistance to ozone and aging have also improved, on the other hand, elongation and abrasion resistance decreased. 2. Tear strength is less influenced by blending and character after aging exhibited the same result. 3. Tensile strength decreased with increase in EPDM contents, especially the ratio of EPDM/NBR are 50/50 and 75/25.

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Cross-section Morphology and Surface Roughness of an Article Manufactured by Material Extrusion-type 3D Printing according to the Thermal Conductivity of the Material

  • Woo, In Young;Kim, Do Yeon;Kang, Hong Pil;Lyu, Min-Young
    • Elastomers and Composites
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    • v.55 no.1
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    • pp.46-50
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    • 2020
  • Material extrusion (ME)-type 3D printing is the most popular among the 3D printing processes. In this study, the cross-section morphologies of ME-type 3D printing manufactured specimens were observed with respect to the thermal properties of the material. The cross-section morphology of a specimen is related to the deposition strength, and the outside profile of the cross-section is related to the surface roughness. The filaments used in this study, with different thermal conductivities, were the acrylonitrile-butadiene-styrene (ABS), the high impact polystyrene (HIPS), the glycol-modified polyethylene terephthalate (PETG), and the polylactic acid (PLA). The cross-sections and the surfaces of the 3D manufactured specimens were examined. In ME-type 3D printing, the filaments are extruded through a nozzle and they form a layer. These layers rapidly solidify and as a result, they become a product. The thermal conductivity of the material influences the cooling and solidification of the layers, and subsequently the cross-section morphology and the surface roughness.

Electrochemical Properties of Diiron Complexes wish Conjugated Chains (공액 사슬을 갖는 철 화합물의 전기화학적 특성)

  • ;Micheal b. Sponsler
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.6
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    • pp.511-517
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    • 2002
  • The complex 1 $([Cp*Fe(CO)_2]_2-(\mu-CH=CH-CH=CH))$ which have butadiene as a bridge were synthesized from $Cp*(CO)_2FeK$ and cis-3,4-dichlorocyclobutene. The derivatives of complex 1 where one or two carbonyl groups are replaced by phosphine ligands have been prepared by photochemical substitution. The new derivatives $([Cp*Fe(L)_2]_2-(\mu-CH=CH-CH=CH))$ where L = $(Ph_2PCH_2CH_2PPh_2)$ and $([Cp*Fe(CO)(L)]_2-(\mu-CH=CH-CH=CH))$ where L : $PPh_3$ have been characterized from $^^1H-$, $^^13C-$,$^^31P-NMR$ and elemental analysis. Obtained complexes have been studied in electrochemical experiment and UV/VIS-near-IR. The mixed-valence radical cation forms of complex 2, 3 species were found to be delocalized as the Class III. Based on the separation of the waves ($\triangle E$ : 0.470 ~ 0.605 V), the efficiency of electronic communication between two metal centers of cation species leading to stabilization relative to neutral species. The phosphine-substitute complexes (2, 3) displays two reversible oxidation waves and oxidation state of metal centers-dependent color change, electrochromism, was observed from yellow to orange and deep blue in methylene chloride.

The Effect of Acrylic Emulsion on Coated Paper Properties (아크릴 에멀젼이 도공지 물성에 미치는 영향)

  • Kim, Sun-Kyung;Park, Yong-Chul;Jung, Hae-Sung;Lee, Yong-Kyu
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.44 no.1
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    • pp.37-42
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    • 2012
  • This study was carried in order to manufacture the high quality coated paper. High quality includes not only physical and optical properties of coated paper but also final print quality. In this study, new acrylic-styrene emulsion was polymerized in laboratory and compared with conventional styrene-butadiene latex. Low-shear viscosity of coating color was decreased with increasing acrylic-emulsion dosage. Small amount of acrylic emulsion addition increased water retention, but further addition decreased it. Acrylic-emulsion addition improved paper gloss, brightness and whiteness, but decreased PPS and opacity slightly. Ink gloss was increased with using No. 3 acrylic-emulsion due to lower ink setting properties. However No. 1 and 2 emulsion showed the opposite result. Surface strength of coated paper was increased with using No. 3 acrylic-emulsion. These results indicate that high quality coated paper can be manufactured with using No. 3 acrylic-emulsion.

Preparation Technique of Thermostable Foam-Floater for High Temperature Engine Oil (고온 엔진오일용 내열성 발포부표 제조 기술)

  • Kim, Byoung-Sik;Hong, Joo-Hee;Chung, Yongjae;Heo, Kwang-Beom
    • Applied Chemistry for Engineering
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    • v.17 no.1
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    • pp.82-86
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    • 2006
  • When a domestically manufactured floater is used in a general gasoline or LPG car, or a flowmeter is floated long time in the engine oil under above $150^{\circ}C$, the floater will be swelled or its organization will be slackened because weight and volume will be changed due to the osmosis of fuel. In this study, we conducted a research on a manufacturing technique of a foam-floater with the small changse in weight and volume, oil-resistance, and thermal resistance in the high temperature engine oil. When the prepared floater TROF II-3, where Nitrile Butadiene Rubber (NBR) as basic material of the floater was superseded by Hydrogenated Nitrile Butadiene Rubber (HNBR), was floated for 100 h at the engine oil of high temperature ($150^{\circ}C$), the change rates of the weight and the volume were 2.90%, and 2.56%, respectively. These were less than the NBR (TROF I-3) case, where the change rates of the weight and the volume were 10.81% and 3.08%, respectively, Therefore, TROF II-3 was determined to be suitable as an engine-oil floater in high temperature because the change of weight and volume were small, the appearance, and the specific gravity of floater were maintained uniformly in the high temperature.

Physical Properties of the Silica-Reinforced Tire Tread Compounds by the Increased Amount of Vulcanization Agents (가교제 증량이 트레드용 실리카 컴파운드의 물성에 미치는 영향)

  • Seo, Byeongho;Kim, Ki-Hyun;Kim, Wonho
    • Elastomers and Composites
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    • v.48 no.3
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    • pp.201-208
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    • 2013
  • In this study, effect of different amounts of sulfur and vulcanization accelerators in the acrylonitrile styrene-butadiene rubber (AN-SBR)/silica compounds on the properties of tire tread compound were studied. As a result, cure rate and degree of cross-linking of the compounds were increased due to enhanced cross-linking reactivity by the increased amounts of sulfur and vulcanization accelerators. Also, abrasion resistance and the mechanical properties such as hardness and modulus of the compounds were improved by enhanced degree of cross-linking of the compounds. For the dynamic properties, tan ${\delta}$ value at $0^{\circ}C$ was increased due to the increase of glass transition temperature ($T_g$) by enhanced degree of cross-linking of the compound, and tan ${\delta}$ value at $60^{\circ}C$ was decreased. Initial cure time ($t_1$) showed the linear relationship with tan ${\delta}$ value at $60^{\circ}C$. This result is attributed that reduced initial cure time ($t_1$) of compounds by applying increased amount of curatives can form cross-linking in early stage of vulcanization that may suppress development of filler network. This result is verified by observation on the surface of annealed compounds using AFM (atomic force microscopy). Consequently, decreased initial cure time is considered a very important parameter to reduce tan ${\delta}$ at $60^{\circ}C$ through reduced re-agglomeration of silica particles.