• Title/Summary/Keyword: chemistry-fiber

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Surface Treatment of Carbon Fiber by Hydrogen Sulfide (탄소섬유 표면의 H2S 처리에 관한 연구)

  • Shin, Kyoung-Han;Han, Jeong-Ryeon
    • Applied Chemistry for Engineering
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    • v.1 no.2
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    • pp.176-181
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    • 1990
  • For the purpose of the improvement of interfacial shear strength in carbon fiber/aluminum matrix composite material, polyacrylonitrile-based carbon fibers were surface treated by hydrogen sulfide gas continuously between 400 and $600^{\circ}C$. Surface treated carbon fibers were analysed by scanning electron microscope. The existence of sulfur compound on treated carbon fiber surfaces was confirmed, and carbon and oxygen contents of the fiber surfaces were examined by X-ray photoelectron spectroscopy. Optimum treating temperature for the adsorption of sulfur on the carbon fiber surface was $500^{\circ}C$. Sulfur compounds on the carbon fiber surfaces form the structures of disulfide, $(S)_n$ and thiophene. The decrease in the tensile strength of the carbon fibers was observed less than about 5%.

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Antimicrobial polyhydroxybutyrate submicron fiber mat loaded with extract of Hypericum perforatum

  • Beran, Milos;Horna, Ales;Vorisek, Viktor;Berkova, Eliska;Korinkova, Radka;Trousil, Vojtech;Hrubanova, Marketa
    • Journal of Plant Biotechnology
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    • v.49 no.3
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    • pp.257-270
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    • 2022
  • The aim of this work was to prepare a new biodegradable polyhydroxybutyrate (PHB) submicron fiber mat loaded with hypericin-rich Hypericum perforatum raw extract by centrifugal spinning technology, an alternative approach to the traditional method of electrospinning to fabricate nanofibers or microfibers from solutions at high speed and low cost. Hypericins in methanol/acetone extract of H. perforatum were determined by UHPLC-MS/MS and HPLC/PDA. Submicron fiber mats composed of pure PHB or PHB enriched with H. perforatum extract were prepared using a pilot plant demonstrator for the centrifugal spinning technology and characterized by SEM. Singlet oxygen production was quantified by the 1,3-diphenylisobenzofuran (DPIBF) method in hexane. The results proved a significant production of singlet oxygen by the prepared submicron fiber mat. We also found a significant antibacterial activity against the bacterial strain Escherichia coli CCM 5417 by a method in accordance with JIS Z 2801/ISO 22196 standards. The H. perforatum extract-enriched PHB submicron fiber mats showed potential for the development of self-cleaning and antimicrobial air filters.

Carbonization and Activation Behaviors of Metal Containing Carbon Fibers (금속함유 탄소섬유의 탄화 및 활성화 거동)

  • Young Ok CHOI;Kap Seung YANG
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.04a
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    • pp.98-100
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    • 2003
  • The efficiency of the adsorption of adsorbents depends on both pore size and shape. In other to adsorb hydrated ion in application of electric double layer capacitor (EDLC), mesopore is necessary[1,2]. Tamai et al.[3] reported that an increased portion of mesopore was introduced through addition of metal or organometallic compound in the precursor and following activation of the carbon fibers with steam. (omitted)

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Microscopic Studies and Simulations of Bloch Walls in Nematic Thin Films

  • Park, Jung-Ok;Zhou, Jian;Srinivasarao, Mohan
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.493-495
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    • 2005
  • The director profiles of the Bloch walls are directly visualized using fluorescence confocal polarizing microscopy. Both pure twist Bloch walls and diffuse Bloch walls are analyzed. Polar anchoring energy was measured from optical simulation of the transmitted light interference pattern or the fluorescence intensity profile of a pure twist wall..

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Synthesis ad Self-assembled Multilayer Film Fabrication via Layer-by-layer Deposition of Water-soluble Aromatic Polyimines

  • Lee, Taek-Seung;Kim, Jae-Hyeon;Kumar, Jayant;Tripathy, Sukant
    • Proceedings of the Korean Fiber Society Conference
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    • 1997.10a
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    • pp.71-75
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    • 1997
  • A new series of water-soluble conjugated aromatic polyimines containing sulfonate groups have been synthesized via polycondensation reaction between diamines and dialdehydes at room temperature. Self-assembled multilayer films consisting each polyimine as a polyanion and poly(diallyldimethylammonium hydrochloride) as a polycation were fabricated successfully by alternate deposition in corresponding aqueous solutions.

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The Preparation and Characterization PVdF Nanofibers Electrostatically Spun (정전방사에 의한 PVdF 나노섬유 제조 및 물성)

  • Cho, Jang-Ik;Kim, Chan;Choi, Chang-Nam;Yang, Gab-Seung
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.04a
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    • pp.382-383
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    • 2003
  • 정전방사란 고분자 용융체 또는 고분자 용액에 전기적인 힘을 이용하여 나노크기의 직경을 가지는 섬유를 제조하는 공정이다. 정전방사에서는 전기적인 힘을 이용하여 기존의 건식 및 습식 방사기술로서 섬유화가 어려웠던 재료들을 간단한 방법으로 섬유화 시킬 수 있으며, 매우 적은 양으로 방사가 불가능했던 재료들에 대해서도 방사가 가능하며, 부직포 형태로 제조된다는 특징이 있다. 본 연구에서는 PVdF계 공중합체 폴리머로서 PVdF-HFP 공중합체를 아세톤 용매에 다양한 농도로 용해시켜 고분자 용액을 제조한 후, 정전방사에 의한 나노크기의 직경의 섬유를 제조하는 방사조건을 고찰하였다. (중략)

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Studies on the Constiuents of Higher Fungi of Korea(XXII) - Comparative Studies on the Constituents of Lentinus edodes Grown on Various Woods - (한국산(韓國産) 고등(高等) 균류(菌類)의 성분(成分) 연구(硏究)(XXII) - 골목에 따른 표고버섯의 성분(成分) 비교(比較) -)

  • Kim, Ha-Won;Kang, Chang-Yuil;Kim, Byong-Kak;Min, Hong-Ki
    • The Korean Journal of Mycology
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    • v.8 no.1
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    • pp.21-23
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    • 1980
  • To investigate constituents of Lentinus edodes grown on various, quantitative analyses of ash, crude protein, crude fiber, crude fat, water, nonsoluble nitrogen of the mushrooms were carried out by ordinary methods. The crude fat of the mushroom grown on chestnut tree(1.82%) was greater than that grown on oak (0.76%) or alder (1.17%) tree. The crude fiber of the mushroom grown on oak tree (12.50%) was greater than those grown on alder and chestnut trees, 9.85% and 8.52%, respectively. The crude protein, ash, nonsoluble nitrogen and water contents of the mushrooms grown on the three different trees were similar.

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Assesment of Chemical Resistance of Geomembranes by UV Exposure (지오멤브레인의 옥외노출시험에 의한 화학저항성 평가)

  • Jeon, Han-Yong;Jung, Gu;Choi, Jun-Dong;Park, Jin-Hyuk;Cho, Sung-Ho
    • Proceedings of the Korean Fiber Society Conference
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    • 2001.10a
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    • pp.424-427
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    • 2001
  • 최근에 지오멤브레인, 지오텍스타일 등의 토목합성재료들이 각종 토목공사에 다양한 용도로 사용되고 있고, 그 사용량이 증가함에 따라 이들 재료들의 각종 성능에 대한 평가가 요구되고 있다. 특히 다양한 원료로 제조된 섬유 고분자 재료들을 적용시킨 현장 시스템의 경우 주변환경에 대한 장기 안정성이 요구되며, 주변환경에 대한 안정성은 제조에 이용되는 고분자의 화학조성에 기인한다. (중략)

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Preparation of $\beta$-Cyclodextrinized Cellulosic Fiber and Deodouring Property ($\beta$-시클로덱스트린화 셀룰로오스 섬유의 제조 및 소취성)

  • Choi, Chang-Nam;Hwang, Tae-Yeon;Ko, Bong-Kook;Kim, Ryong;Hong, Sung-Hak;Kim, Sang-Yool
    • Polymer(Korea)
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    • v.25 no.5
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    • pp.635-641
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    • 2001
  • $\beta$-Cyclodextrine/benzoic acid complex was prepared and reacted with cyanuric chloride (2,4,6-trichloro-1,3,5-triazine). Identification of complex formation and reaction was checked by FT-IR, UV-Vis, and EDX. By reacting this material with cotton fiber, the deodourant fiber was prepared. The deodourizing property was evaluated by the concentration changes of aqueous ammonia solution after flowing ammonia gas through the column titled with deodourant fiber prepared. The deodourizing property was increased with an increase of concentration of $\beta$-cyclodextrine unit in the fiber. In the case of $\beta$-cyclodextrine/benzoic acid complex, the deodourzing property was much increased, comparing with the $\beta$-cyclodextrine only. It was considered to be the binding of aamonia gas caused by benzoic acid in the complex.

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Trend of Carbon Fiber-reinforced Composites for Lightweight Vehicles (자동차 경량화를 위한 탄소섬유강화 복합재료의 동향)

  • Kim, Ki-Seok;Bae, Kyong-Min;Oh, Sang-Yeob;Seo, Min-Kang;Kang, Chang-Gi;Park, Soo-Jin
    • Elastomers and Composites
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    • v.47 no.1
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    • pp.65-74
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    • 2012
  • Recently, the need of developing eco-friendly materials has been required with restriction strengthening on environment and energy saving by the resource depletion worldwide. These trends are not an exception in transport industry including automobile. In addition, these materials have to fulfill not only the high quality and cheap price but also the high-performance which meet the needs of costumer and society. Among the various materials, carbon fiber-reinforced composite which is actively studying for lightweight of the automobile is one of the most suitable candidates. Indeed, the carbon fiber-reinforced composites are used as the essential materials to substitute body and other parts in automobile and the demand is increasing largely. Carbon fiber-applied automobile has improved brake, steering, durability and high fuel efficiency, leading to the energy conservation and minimizing carbon dioxide emissions. This paper focuses on the necessity of carbon fiber-reinforced composites for lightweight of automobile and its technical trends.