• Title/Summary/Keyword: solvent-resistance

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Synthesis of Co(II), Ni(II) and Cu(II) Complexes from Schiff base Ligand and Reactivity Studies with Thermosetting Epoxy Resin

  • Lakshmi, B.;Shivananda, K.N.;Prakash, Gouda Avaji;Rama, Krishna Reddy K.;Mahendra, K.N.
    • Bulletin of the Korean Chemical Society
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    • v.32 no.5
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    • pp.1613-1619
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    • 2011
  • A hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) containing Co(II), Ni(II) and Cu(II) ions was prepared by curing N-MPGE and tetradentate Schiff base Co(II), Ni(II) and Cu(II) complexes. The curing polymerization reaction of N-MPGE with metal complexes as curing agents was studied. The cured samples were studied for thermal stability, chemical (acid/alkali/solvent) and water absorption resistance and homogeneity of the cured systems. The tetradentate Schiff base, 3-[(Z)-2-piperazin-1-yl-ethylimino]-1,3-dihydro indol-2-one was synthesized by the condensation of Isatin (Indole-2, 3-dione) with 1-(2-aminoethyl)piperazine (AEP). Its complexes with Co(II), Ni(II) and Cu(II) have been synthesized and characterized by microanalysis, conductivity, Uv-Visible, FT-IR, TGA and magnetic susceptibility measurements. The spectral data revealed that the ligand acts as a neutral tetradentate Schiff base and coordinating through the azomethine nitrogen, two piperazine nitrogen atoms and carbonyl oxygen.

Effect of centrifugation on the structure and properties of silk sericin

  • Park, Chun Jin;Um, In Chul
    • International Journal of Industrial Entomology and Biomaterials
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    • v.33 no.2
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    • pp.144-148
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    • 2016
  • Recently, silk sericin has been studied extensively for biomedical and cosmetic applications because of its unique properties, including UV resistance and wound healing ability. For use in applications, sericin is fabricated in various forms including films and gels. However, the mechanical properties of sericin are too weak. In this basic study on improving the mechanical properties of sericin, a silk sericin aqueous solution was separated into two layers by centrifugation. The solution viscosity, molecular conformation, and mechanical properties of each separation layer of the sericin were examined. Sericin from the lower layer had a higher solution viscosity and film mechanical properties (strength and strain) than that from the upper layer, implying that sericin from the lower layer had a higher molecular weight than that from the upper layer. The molecular conformation of the sericin films varied depending on the casting solvent. In aqueous solution, the sericin film from the lower layer showed a ${\beta}$-sheet conformation, whereas that from the upper layer displayed a random coil conformation. All the sericin films showed a highly ${\beta}$-sheet-crystallized state when cast in formic acid, regardless of the separation layer.

Effect of MWCNTs/PSf support layer on the performance of polyamide reverse osmosis membrane (탄소나노튜브가 첨가된 폴리술폰 지지체가 폴리아미드 역삼투막의 성능에 미치는 영향)

  • Min, Choong-Sik;Kim, Seung-Hyun
    • Journal of Korean Society of Water and Wastewater
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    • v.34 no.2
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    • pp.127-137
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    • 2020
  • In this study, a MWCNT(multi-wall carbon nanotube) was added to polysulfone(PSf) support layer to improve flux of TFC(thin film composite) RO(reverse osmosis) membrane. Two different kinds of MWCNT were used. Surfaces of some MWCNTs were modified hydrophilically through acid treatment, while those of other MWCNTs were modified through heat treatment to maintain their hydrophobicity. MWCNT/PSf support layer was prepared by adding PSf to the NMP mixed solvent containing 0.1 wt% MWCNTs using a phase inversion method. The surface porosity of the MWCNT/PSf support increased by 42~46% while its surface pore size being maintained. The TFC RO membrane made of MWCNT/PSf support layer showed a 20% flux increase while its salt rejection characteristics is sustained. In addition, the MWCNT/PSf support layer has better mechanical stability than the PSf support layer, there resulting in an increased resistance of flux reduction due to physical pressure.

A Study of Chain extension and Synthesis in Waterborne Polyurethane-Epoxy Hybrid Resin (수용성 하이브리드수지(폴리우레탄-에폭시)의 합성 및 사슬 연장에 관한 연구)

  • Lee, Joo-Youb;Kim, Ki-Jun
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.1
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    • pp.109-117
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    • 2011
  • In this study, we experimented that how influence chain extension to waterborne urethane-epoxy hybrid resin for leather garment coatings. First of all, We had analyzed datas by FT-IR, SEM and machanical properties. By instruments analysis measurement we confirmed that synthesis of epoxy and hybrid resin. In this experiment we knew that polyurethane-epoxy hybrid resin have 5 grades of solvent resistance. Tensile strength measured in the polyurethane-epoxy resin(EDA 5.37g, 2.386 $kg_f/mm^2$) had the most strong strength.. Also polyurethane-epoxy hybrid resin had better result(EDA 5.37g. 37.4 mg. loss) than other hybrid resins. As hight proportion of EDA in hybid resin, we obtained low elongation and low flexibility. In this result, chain extension of waterborne polyurethane-epoxy hybrid resin showed that how effect in leather coating by ratio of EDA.

Fabrication of ITO-Free organic photovoltaic cells by ink-jet printing (잉크젯 기법을 이용한 ITO-Free 유기태양전지 제작)

  • Lee, Ue-Jin;Yoon, Jong-Jin;Kim, Seung-Taek;Cho, Young-June;Lee, Sang-Ho
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1714-1715
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    • 2011
  • In this work, highly conductive organic solvent-based polyaniline(PANI) was used as an anode in organic photovoltaic cells (OPV) based on poly - (3-hexylthiophene) and [6,6] - phenyl - C60 - butyricacid methyl ester (P3HT : PCBM). The transmittance of the used PANI film were 87.67% and 86.57% at 550nm, and its sheet resistance were 454 ${\Omega}/{\Box}$ and 298 ${\Omega}/{\Box}$. We fabricated ITO-free OPV cells using PANI as an anode, which exhibited an external power conversion efficiency of 2.28% with a result of Jsc of 6.922mA/cm2, Voc of 0.6093V, and FF of 54.10% under an illumination of air mass(AM) 1.5G (100mW/$cm^2$). We used ink-jet printing to deposit buffer layer and active layer on a glass substrate.

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A Research on the MIM Process of High-Precision Fuze Parts (고정밀 신관 부품의 MIM 공정에 관한 연구)

  • Seo, Jung-Hwa;Kang, Kyeoung-Hoon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.15 no.3
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    • pp.231-240
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    • 2012
  • During the past two decades, Metal Injection Molding(MIM) has become a very competitive technology to fabricate small, precise and complex-shaped parts in large quantities. In this research, the applicability of MIM technology in the mass-production of the high precision fuze parts to save manufacturing cost was investigated. The water-atomized 17-4PH stainless steel powder, one of the best corrosion-resistant high strength materials, was injection-molded into real-shape fuze part and flat tensile specimens. The injection-molded parts were thermally debound in hydrogen gas flow without solvent extraction. Sintering of the debound parts was carried out in vacuum at temperatures ranging from $1150^{\circ}C$ to $1370^{\circ}C$. The sintering behavior, mechanical properties, dimensional precision, corrosion resistance of the MIMed 17-4PH stainless parts were investigated. It was found that almost all the properties of the MIMed parts were comparable to those of the mechanically machined parts. Also, actual military field tests using both MIMed and mechanically machined fuze parts were performed as well and were found to be very successful.

The Characteristic Changes of Electromagnetic Wave Absorption in Fe-based Nanocrystalline P/M Sheet by the Additions of BaTiO3 Powder and Dispersant (BaTiO3 분말과 분산제 첨가에 따른 Fe계 나노결정 P/M시트의 전자파흡수 특성변화)

  • Kim, Mi-Rae;Cho, Hyeon-Jeong;Park, Won-Wook
    • Journal of Powder Materials
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    • v.15 no.1
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    • pp.53-57
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    • 2008
  • The amorphous $Fe_{73}Si_{16}B_7Nb_3Cu_1$(at%) alloy strip was pulverized using a jet mill and an attrition mill to get flake-shaped powder. The flake powder was mixed with dielectric $BaTiO_3$ powder and its dispersant to increase the permittivity. The powders covered with dielectric powders and its dispersant were mixed with a binder and a solvent and then tape-cast to form sheets. The absorbing properties of the sheets were measured to investigate the roles of the dielectric powder and its dispersant. The results showed that the addition of $BaTiO_3$ powders and its dispersant improved the absorbing properties of the sheets noticeably. The powder sheet mixed with 5 wt% of $BaTiO_3$ powder and 1 wt% of dispersant showed the best electromagnetic wave absorption rate because of the increase of the permittivity and the electrical resistance.

Feasibility of Indium Tin Oxide (ITO) Swarf Particles to Transparent Conductive Oxide (TCO)

  • Hong, Sung-Jei;Yang, DuckJoo;Cha, Seung Jae;Lee, Jae-Yong;Han, Jeong-In
    • Current Photovoltaic Research
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    • v.3 no.2
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    • pp.50-53
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    • 2015
  • Indium (In) is widely used for transparent electrodes of photovoltaics as a form of indium tin oxide (ITO) due to its superior characteristics of environmental stability, relatively low electrical resistivity and high transparency to visible light. However, In has been worn off in proportion to growth the In related market, and it leads to raise of price. Although In is obtained from ITO target scarps, much harmful elements are used for the recycling process. To decrease of harmful elements, ITO swarf particles obtained from target scraps was characterized whether it is feasible to transparent conductive oxide (TCO). The ITO swarf was crushed with milling process, and it was mixed with new ITO nanoparticles. The mixed particles were well dispersed into ink solvent to make-up an ink, and it was well coated onto glass substrate. After heat-treatment at $400^{\circ}C$ under $N_2$ rich environments, optical transmittance at 550 nm and sheet resistance of the ITO ink coated layer was 71.6% and $524.67{\Omega}/{\square}$, respectively. Therefore, it was concluded that the ITO swarf was feasible to TCO of touch screen panel.

A study on synthesis and mechanical properties polyurethane-acrylic hybrid resin with milk casein (Milk casein을 이용한 수용성 polyurethane-acrylic hybrid resin의 합성 및 물성 영향에 관한 연구)

  • Lee, Joo-Youb;Nam, Sang-Sung
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.3
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    • pp.567-574
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    • 2013
  • For this research, prepared water soluble milk casein resin and waterborne polyurethane-acrylic resin. Use these resin, this article has been analyzed about change of mechanical properties by increasing amount of casein resin in polyurethane-acrylic resin on coated leather. According to measure data for solvent resistance, WPA(waterborne polyurethane-acrylic resin) resin and WPA-C1, C2, C3(samples of polyurethane-acrylic resin with milk casein resin) had good property. As known in the results, increase of casein constant did not influence to big change of hybrid resin properties. As test of tensile strength, WPA had lowest tensile characteristic(1.598 $kg_f/mm^2$) and WPA-C3 had highest tensile characteristic(1.718 $kg_f/mm^2$). Also best properties of abrasion was WPA-C3(06.021 mg.loss). In elongation case, WPA had best properties(754 %) in this experiment.

Distribution of Zr(IV) Ion Species in Aqueous Solution (수용액(水溶液)에서 지르코늄이온의 농도분포(濃度分布))

  • Lee, Man-Seung;Lee, Hwa-Young
    • Resources Recycling
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    • v.20 no.6
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    • pp.56-62
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    • 2011
  • Zirconium is used in nuclear reactors as a structural material due to its excellent corrosion resistance and to low neutron crosssection. Variation in the distribution and solubility of Zr(IV) with solution pH was obtained. Distribution of Zr(IV) containing species in HCl and $HNO_3$ solution was analyzed by considering the complex formation of Zr(IV) species with the anion of the inorganic acid. Bromley interaction parameter between $ZrO^{2+}$ and nitrate ion was estimated by using the reported data on the solvent extraction of Zr(IV) by Cyanex272 from $HNO_3$ solution. This Bromley parameter can be utilized in calculating extraction isotherm of Zr(IV) and in predicting the separation factor between Zr(IV) and Hf(IV).