• 제목/요약/키워드: chemistry-fiber

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Influence of Fiber Array Direction on Mechanical Interfacial Properties of Basalt Fiber-reinforced Composites (현무암섬유 섬유 배향에 따른 현무암섬유 강화 복합재료의 기계적 계면특성 영향)

  • Kim, Myung-Seok;Park, Soo-Jin
    • Polymer(Korea)
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    • v.39 no.2
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    • pp.219-224
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    • 2015
  • In this work, the effect of fiber array direction including $0^{\circ}$, $0^{\circ}/90^{\circ}$, $0^{\circ}/45^{\circ}/-45^{\circ}$ was investigated for mechanical properties of basalt fiber-reinforced composites. Mechanical properties of the composites were studied using interlaminar shear strength (ILSS) and critical stress intensity factor ($K_{IC}$) measurements. The cross-section morphologies of basalt fiber-reinforced epoxy composites were observed by scanning electron microscope (SEM). Also, the surface properties of basalt fibers were determined by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). From the results, it was observed that acid treated basalt fiber-reinforced composites showed significantly higher mechanical interfacial properties than those of untreated basalt fiber-reinforced composites. These results indicated that the hydroxyl functional groups of basalt fibers lead to the improvement of the mechanical interfacial properties of basalt fibers/epoxy composites in the all array direction.

Adsorptive Removal of Cu(II), Pb(II), and Hg(II) Ions from Common Surface Water Using Cellulose Fiber-Based Filter Media

  • Phani Brahma Somayajulu Rallapalli;Jeong Hyub Ha
    • Applied Chemistry for Engineering
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    • v.35 no.4
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    • pp.352-359
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    • 2024
  • Environmental pollution from heavy metal ions (HMIs) is a global concern. Recently, biosorption methods using cellulose sorbents have gained popularity. The objective of this study was to assess the removal efficiency of Cu(II), Pb(II), and Hg(II) ions at low concentration levels (100-700 ppb) from aqueous solutions using three different cellulose fiber-based filter media. Sample A was pure cellulose fiber, Sample B was 10% activated carbon-cellulose fiber, and Sample C was cellulose fiber-glass fiber-30% activated carbon-20% amorphous titanium silicate (ATS). The samples were characterized by several physicochemical techniques. The porosity measurements using N2 sorption isotherms revealed that Samples A and B are nonporous or macroporous materials, whereas the addition of 50% filler materials into the cellulose resulted in a microporous material. The Brunauer-Emmett-Teller (BET) surface area and pore volume of Sample C were found to be 320.34 m2/g and 0.162 cm3/g, respectively. The single ion batch adsorption experiments reveal that at 700 ppb initial metal ion concentration, Sample A had removal efficiencies of 7.5, 11.5, and 13.7% for Cu(II), Pb(II), and Hg(II) ions, respectively. Sample B effectively eliminated 99.6% of Cu(II) ions compared to Pb(II) (14.2%) and Hg(II) (31.9%) ions. Cu(II) (99.37%) and Pb(II) (96.3%) ions are more efficiently removed by Sample C than Hg(II) (68.2%) ions. The X-ray photoelectron spectroscopy (XPS) wild survey spectrum revealed the presence of Cu(II), Pb(II), and Hg(II) ions in HMI-adsorbed filter media. The high-resolution C1s spectra of Samples A and B reveal the presence of -C-OH and -COOH groups on their surface, which are essential for HMIs adsorption via complexation reactions. Additionally, the ATS in Sample C facilitates the adsorption of Pb(II) and Hg(II) ions through ion exchange.

Photochromic and thermal properties of poly (Vinyl alcohol)/ $H_6P_2W_{18}O_{62}$ hybrid membranes (폴리비닐알코올 $H_6P_2W_{18}O_{62}$ hybrid membranes의 광색 및 열적 특성)

  • Jian Gong;Kim, Hak-Yong;Lee, Duck-Rae;Bin Ding;Xiangdan Li
    • Proceedings of the Korean Fiber Society Conference
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    • 2002.04a
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    • pp.459-461
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    • 2002
  • A new class of materials based on organic and inorganic species combined at a molecule level has obtained more attention recently[1]. HPA(heteropolyacid) shows unmatched applied perspective in terms of synthesis chemistry, analysis chemistry, biology, medicine and materials science[2]. As a potential photochemical material, the hybrid system of HPA and polymer has been investigated. However, the design and synthesis of heteropolyacid-based hybrids, which are at the forefront of the materials chemistry research, is still in its infancy. (omitted)

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Preparation and Electric Double Layer Capacitance of Mesoporous Carbon

  • Shiraishi, Soshi;Kurihara, Hideyuki;Oya, Asao
    • Carbon letters
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    • v.1 no.3_4
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    • pp.133-137
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    • 2001
  • Mesoporous activated carbon fiber (ACF) was prepared from phenolic resin containing a small amount (0.1 wt %) of organic nickel complex through carbonization and steam activation. Microporous ACF as reference sample was also prepared from phenolic resin without agent. In both cases of the mesoporous ACFs and the microporous ACFs, the electric double layer capacitance of the nonaqueous electrolyte (0.5 M $TEABF_4$/PC or 1.0 M $LiClO_4$/PC) was not proportional to the BET specific surface area. This is owing to the low permeability of nonaqueous electrolyte or the low mobility of ion in narrow micropores. However, the mesoporous ACF showed higher double layer capacitance than the microporous (normal) ACF. This result suggests that the presence of many mesopores promotes the formation of effective double layer or the transfer of ion in the micropore.

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Quality Prediction of Alfalfa Hay by Near Infraced Recfletance Spectroscopy (NIRS) (Near Infraced Recfletance Spectroscopy ( NIRS ) 에 의한 알팔파 건초의 품질 평가)

  • ;N. P. Martin
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.9 no.3
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    • pp.163-167
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    • 1989
  • Near infrared reflectance spectroscopy (NIRS) analysis of commercial farm alfalfa hay for crude prowin (CP), neutral detergent fiber(NDF), and acid detergent fiber(ADF) was compared with wet chemistry results. There were no differences between NIRS and wet chemistry results in CP and ADF content, but there were differences (P <.05) between NIRS and wet chemistry results for sample No.2, 4, 5 in NDF content.

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Effect of chemically reduced graphene oxide on epoxy nanocomposites for flexural behaviors

  • Lee, Seul-Yi;Chong, Mi-Hwa;Park, Mira;Kim, Hak-Yong;Park, Soo-Jin
    • Carbon letters
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    • v.15 no.1
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    • pp.67-70
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    • 2014
  • In this work, nanocomposites of epoxy resin and chemically reduced graphene oxide (RGO) were prepared by thermal curing process. X-ray diffractions confirmed the microstructural properties of RGO. Differential scanning calorimetry was used to evaluate the curing behaviors of RGO/epoxy nanocomposites with different RGO loading amounts. We investigated the effect of RGO loading amounts on the mechanical properties of the epoxy nanocomposites. It was found that the presence of RGO improved both flexural strength and modulus of the epoxy nanocomposites till the RGO loading reached 0.4 wt%, and then decreased. The optimum loading achieved about 24.5 and 25.7% improvements, respectively, compared to the neat-epoxy composites. The observed mechanical reinforcement might be an enhancement of mechanical interlocking between the epoxy matrix and RGO due to the unique planar structures.

Cellulose-based carbon fibers prepared using electron-beam stabilization

  • Kim, Min Il;Park, Mi-Seon;Lee, Young-Seak
    • Carbon letters
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    • v.18
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    • pp.56-61
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    • 2016
  • Cellulose fibers were stabilized by treatment with an electron-beam (E-beam). The properties of the stabilized fibers were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The E-beam-stabilized cellulose fibers were carbonized in N2 gas at 800℃ for 1 h, and their carbonization yields were measured. The structure of the cellulose fibers was determined to have changed to hemicellulose and cross-linked cellulose as a result of the E-beam stabilization. The hemicellulose decreased the initial decomposition temperature, and the cross-linked bonds increased the carbonization yield of the cellulose fibers. Increasing the absorbed E-beam dose to 1500 kGy increased the carbonization yield of the cellulose-based carbon fiber by 27.5% upon exposure compared to untreated cellulose fibers.

Development of Composite Hollow Fiber Membranes for Olefin Off-gas Recovery (올레핀 배가스의 분리를 위한 중공사형 복합막의 개발)

  • Kim Jeong-Hoon;Choi Seung-Hak;Lee Soo-Bok
    • Membrane Journal
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    • v.15 no.2
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    • pp.157-164
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    • 2005
  • In this study, composite hollow fiber membranes were developed for the recovery of olefin monomers in polyolefin industry off-gases. Polyetherimide (PEI) hollow fiber support membranes were fabricated from spinning solutions containing PEI, NMP and polyethylene glycol (PEG). The influence of dope solution and inner coagulant composition on the permeation properties and structure of hollow fiber supports was examined. PDMS was used as a selective layer and coated on PEI hollow fiber support. The thickness of active layer was controlled by changing coating solution concentration. The permeation properties of hollow fiber supports and composite membranes were characterized with a pure gas permeation test. The optimized composite hollow fiber membrane has $10\;{\mu}m$ selective layer and shows excellent separation performance; the ideal selectivity of olefins over nitrogen is in the following order: 1-butylene (6.4) > propylene (17) > ethylene (97), which selectivity data are similar to the intrinsic olefin/nitrogen selectivities of PDMS. This confirms that the new composite hollow fiber membranes suitable for olefin off-gas recovery has developed successfully.