• Title/Summary/Keyword: Chemical coupling

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Synthesis of Cephalosporins Having a Heterocyclic Group at the C-3 Position

  • Myung Hee Jung;Kul-Woong Cho;Wan Joo Kim;Joon-Seob Shin;Choong Sil Park
    • Bulletin of the Korean Chemical Society
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    • v.14 no.1
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    • pp.32-38
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    • 1993

  • 3-(3-Bromotetrahydrofuran-2-yl)-3-cephem 7 was obtained from 3-(2-hydroxyethyl)vinyl-3-cephem 6 by the cyclization reaction using N-bromosuccinimide. Compound 5 was prepared by Wittig reaction, namely a coupling of cephem-derived triphenylphosphonium salt 3 with aldehyde component 4 in the presence of base.

  • https://doi.org/10.5012/bkcs.1993.14.1.32 인용 PDF

Effects of Coupling Agents and Clay on the Physical Properties of Wood Flour/Polyethylene Composites (커플링제 및 점토가 목분/폴리에틸렌 복합체의 물성에 미치는 영향)

  • Park, Byung-Sub;Kim, Dae-Su
    • Polymer(Korea)
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    • v.35 no.2
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    • pp.124-129
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    • 2011

  • Wood plastic composites (WPCs) are attracting a lot of interest recently. In this study, wood flour/polyethylene (PE) composites panels comprised of a coupling agent and nanoclay were prepared by melt-blending followed by compression molding. Five maleic anhydride grafted polyethylene (MAPE) coupling agents were tested, and the best choice and its optimum content were determined. The mechanical properties of the WPCs were measured by UTM, and the thermal properties were measured by TGA, DMA, DSC, and TMA. Adding just a small amount (1 phr) of organoclay made the tensile and flexural strength and the crystallinity of the WPC somewhat increase and the storage modulus and dimensional stability of the WPC largely increase. SEM images showed that the coupling agent drastically improved wood flour/PE interfacial bonding. Selecting the best coupling agent optimized content and adding a small amount of organoclay resulted in a high performance wood flour/PE composite.

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