• Title/Summary/Keyword: chemical functionalization

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Functionalization of graphene nanoplatelets using sugar azide for graphene/epoxy nanocomposites

  • Bose, Saswata;Drzal, Lawrence T.
    • Carbon letters
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    • v.16 no.2
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    • pp.101-106
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    • 2015
  • We report a covalent functionalization of graphene nanoparticles (GnPs) employing 2,3,4-Tri-O-acetyl-${\beta}$-D-xylopyranosyl azide followed by fabrication of an epoxy/functionalized graphene nanocomposite and an evaluation of its thermo-mechanical performance. Successful functionalization of GnP was confirmed via thermal and spectroscopic study. Raman spectroscopy indicated that the functionalization was on the edge of the graphene sheets; the basal plane was not perturbed as a result of the functionalization. The epoxy/functionalized GnP composite system exhibited an increase in flexural modulus (~18%) and glass transition temperature (${\sim}10^{\circ}C$) compared to an un-functionalized GnP based epoxy composite.

Wear Characteristics and Thermal Stability of PA66/silane treated MoS2 Composites

  • Nam, Ki-dong;Gu, Bo-ram;Ryu, Sung-hun
    • Elastomers and Composites
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    • v.55 no.4
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    • pp.339-346
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    • 2020
  • We functionalized a wear-resistant carbon-based MoS2 filler to solve its limited wear condition problem. The filler exhibits excellent lubricative properties. The surface modification of MoS2 was carried out using a (3-glycidyloxypropyl)trimethoxysilane (GPTMS) silane coupling agent to improve the low compatibility and dispersibility of the filler that generally degrade the performance of composites. A silane coupling agent was employed for the functionalization of MoS2, and its effect on the wear resistance of MoS2/Polyamide-6,6 was investigated. The silanization of MoS2 was identified by contact angle analysis and Fourier-transform infrared, energy dispersive X-ray, and X-ray photoelectron spectroscopies. The wear resistance of the composite was found to be improved significantly by the surface functionalization of MoS2.

Anionic Synthesis of Dipyridine Chain End-Functionalized Polystyrene and Polybutadiene (리빙 음이온 중합에 의한 Dipyridine 말단 관능화 폴리스티렌 및 폴리부타디엔의 합성)

  • Ji, Sang-Chul;Lee, Jong-Seop;Kim, Doo-Hwan;Kang, Cheol-Han;Park, Jong-Hyuk;Lee, Bum-Jae
    • Polymer(Korea)
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    • v.34 no.2
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    • pp.159-165
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    • 2010
  • Dipyridine-terminated polystyrenes and polybutadienes were synthesized by the chain endfunctionalization reaction of polystyryllithium (PSLi) and polybutadienyllithium (PBDLi) with di(2-pyridyl) ketone(DPK) using a living anionic polymerization method in the Ar-glove box. Living polymeric lithiums with low molecular weights (Mw=1000~2000 g/mol) were used to investigate the chain end-functionalization yield with DPK and the degree of coupling reaction by the attack of organolithium to the pyridine ring in the presence of TMEDA using GPC, $^1H$-NMR, $^{13}C$ analysis. DPK-terminated PBD exhibited much higher functionalization yield and less amount of coupling reaction compared with DPK-terminated PS. 86% functionalization yield with 9% degree of coupling was obtained when the PBDLi was added dropwise to DPK solution at room temperature. The functionalization yield was increased as the reaction temperature decreased, however, no LiCl effect was observed in this chain end-functionalization reaction with DPK.

Theoretical Investigation of Edge-modified Zigzag Graphene Nanoribbons by Scandium Metal with Pyridine-like Defects: A Potential Hydrogen Storage Material

  • Mananghaya, Michael
    • Bulletin of the Korean Chemical Society
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    • v.35 no.1
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    • pp.253-256
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    • 2014
  • Functionalization of zigzag graphene nanoribbon (ZGNR) segment containing 120 C atoms with pyridine (3NV-ZGNR) defects was investigated on the basis of density-functional theory (DFT) calculations, results show that edge-modified ZGNRs by Sc can adsorb multiple hydrogen molecules in a quasi-molecular fashion, thereby can be a potential candidate for hydrogen storage. The stability of Sc functionalization is dictated by a strong binding energy, suggesting a reduction of clustering of metal atoms over the metal-decorated ZGNR.

Influence of Functionalization on Physicochemical Properties of Multi-walled Carbon Nanotubes/Epoxy Matrix Nanocomposites

  • Seo, Min-Kang;Park, Soo-Jin
    • Bulletin of the Korean Chemical Society
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    • v.30 no.1
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    • pp.124-128
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    • 2009
  • In this study, the effect of multi-step purification or functionalization on physicochemical properties of multi-walled carbon nanotubes (MWNTs)/epoxy (EP) nanocomposites was investigated. The nanocomposites containing multi-step purified MWNTs showed a stronger influence on $T_g$ and increased in mechanical properties in comparison to nanocomposites containing the same amount of only purified MWNTs. Consequently, the multi-step purification of MWNTs led to an improvement of thermomechanical properties of nanocomposites, resulting from improving the intermolecular interaction of MWNTs in epoxy matrix resins.

Total Synthesis of a New 7-Deoxyidarubicinone Derivative through the Functionalization of an A-Ring Side Chain

  • Rho, Young S.;Go, Hyeon Gyeong;Kim, Wan Jung;Yu, Dong Jin;Gang, Hyeon Su
    • Bulletin of the Korean Chemical Society
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    • v.21 no.8
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    • pp.774-778
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    • 2000
  • A convenient total synthesis of a new 7-deoxyidarubicinone ivative21,the aglycon of the anticancer anti-biotic idarubicin analogue,is described.Keyfeatures of the synthesis are the Friedel-Crafts acylation and the functionalization of an A-ring si de chain. A synthon 14 for the A and B rings was prepared from intermediate 6 in five steps.