• 제목/요약/키워드: porous polymer

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열가소성 고분자를 이용한 다공질 알루미나의 제조 (Fabrication of Porous Al2O3 Ceramics Using Thermoplastic Polymer)

  • 이상진;김해두
    • 한국세라믹학회지
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    • 제41권7호
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    • pp.513-517
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    • 2004
  • 기공크기와 형태를 제어하여 열전도도 이방성을 나타내기 위해 판상의 기공이 배향된 다공질 알루미나 소결체의 제조방법을 연구하였다. 속이 가스로 차있는 열가소성 고분자 microsphere를 알루미나 분말과 혼합한 후 일축 가압 열변형 방법을 이용하여 15 MPa의 압력으로 가압한 상태에서 20$0^{\circ}C$까지 승온하여 microsphere를 판상으로 변형시킨 후, 1,00$0^{\circ}C$에서 1시간동안 소결하였다. Microsphere의 함량이 10wt%인 경우 45.3%의 기공율을 나타내었으며, 44 MPa의 꺾임강도 값을 나타내었다. 미세구조를 살펴본 결과 판상기공이 압축방향과 수직방향으로 배향되었으며, 열전도도를 측정한 결과 압축방향으로 3.803 W/mK, 측면방향으로는 7.818 W/mK로서 두 값의 비는 2 이상이었다.

Fabrication of Conducting Polymer Nanowires using Block Copolymer Nano-porous Templates for Photovoltaic Device

  • Lee, Jeong-In;Yu Jae-Woong;Kim, Jin-Kon;Russell Thomas P.
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.312-312
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    • 2006
  • Block copolymers with well-defined nanoscopic structures have recently gained much attention for their potential uses as functional nanostructures. Here, we show that nanoporous templates made from polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) satisfy a novel design concept. At first, arrays of nanoscopic cylindrical microdomains oriented normal to the surface can easily be prepared. Then, we fabricated ultra high density arrays of conducting polymer as poly(pyrrole) (Ppy) and poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires with diameters of $25{\sim}40\;nm$ on the ITO glass by electropolymerization of the monomers inside nanoholes. These high density arrays of conducting polymer nanowires could be used as P-type materials for photovoltaic devices.

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폴리카보실란 에멀젼의 동결건조를 이용한 다공체 SiC 제조 (Preparation of Porous SiC by Freeze Drying of Polycarbosilane Emulsion)

  • 황연
    • 한국재료학회지
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    • 제26권6호
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    • pp.320-324
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    • 2016
  • Porous SiC beads were prepared by freeze-drying a polycarbosilane (PCS) emulsion. The water-in-oil (w/o) emulsion, which was composed of water, PCS dissolved p-xylene, and sodium xylenesulfonate (SXS) as an emulsifier, was frozen by dropping it onto a liquid $N_2$ bath; this process resulted in 1~2 mm sized beads. Beads were cured at $200^{\circ}C$ for 1 h in air and heat-treated at $800^{\circ}C$ and $1400^{\circ}C$ for 1 h in an Ar gas flow. Two types of pores, lamella-shaped and spherical pores, were observed. Lamellar-shaped pores were found to develop during the freezing of the xylene solvent. Water droplets in the w/o emulsion were changed into spherical pores under freeze-drying. At $1400^{\circ}C$ of heat-treatment, porous SiC was synthesized with a low level of impurities.

다공성 미소구체 중 초산토코페롤의 봉입에 관한 연구 (The Entrapment of Vitamin E Acetate in Porous Spheres)

  • 양윤정;배봉진;이규식;전인구
    • Journal of Pharmaceutical Investigation
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    • 제21권1호
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    • pp.51-55
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    • 1991
  • Porous spheres composed of natural waxes and inorganic materials containing vitamin E acetate as a drug were prepared by impregnation method. Furthermore, the amount of vitamin E acetate entrapped in the spheres and the release rate of vitamin E acetate from the spheres were studied. The impregnation of vitamin E acetate was carried out by dipping the spheres in vitamin E acetate solutions. Entrapment mechanism of vitamin E acetate could be expressed in terms of Langmuir's adsorption isotherm. The amount of vitamin E acetate entrapped in porous spheres was influenced by the structure and concentration of the polymer used in vitamin E acetate solutions, and the concentration of vitamin E acetate. Release characteristics of vitamin E acetate from the spheres were investigated by withdrawing samples periodically and analyzing them by spectrophotomer.

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다공성 세라믹스와 다공질층을 포함하는 적층체의 제조에 관한 연구;I. 기공구조 (Fabrication of Porous Ceramics and Multi-layered Ceramics Containing Porous Layers; I. Pore Structure)

  • 이해원;윤복규;송휴섭
    • 한국세라믹학회지
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    • 제31권9호
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    • pp.1044-1052
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    • 1994
  • Tape casting technique was successfully applied to produce porous ceramics and multi-layered ceramics containing porous layers, where spherical hollow polymer particles were introduced as pore precursors. In the presence of extreme differences in density and size between Al2O3 and pore precursor particles, hindered settling was effective in preventing segregation of component particles and packing behavior of mixed powders was improved through bimodal packing. There were two transitions in packing behavior of mixed powders. The first transition took place at 40~50 vol% pore precursor addition, where majority of pores changed from close to open pore state. The other transition occured at 60~70 vol% pore precursor addition, where pore precursor particles formed a continuous network structure.

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유기물 첨가에 따른 다공성 실리카 세라믹스의 제조 및 특성(I) (Synthesis and Characteristics of Porous Silica Ceramics with Organic Additives(I))

  • 신진용;이범재;노재성
    • 한국세라믹학회지
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    • 제35권9호
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    • pp.958-968
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    • 1998
  • Porous silica ceramics were prepared using DCCA(Drying Control Chemical Additives) Such as uncharged polymer(Polyethylene glycol) and protein (Lipase) under H2O/Low-grade TEOS=10 C2H5OH/Low-grade TEOS=1 HC1/Low=grade TEOS=0.01 After Plain which doesn't added DCCA and samples of 11 sorts which varied molecular weight of PEG(Mw=600, 1000, 2000) quantity of Lipase and concentration of wat-er were synthesized gellation time and thermal analysis were investigated. After heat-treated at 600, cry-stal structures analyses of SiO2 polymer and characteristics of pores were investigated. Gellation time was retarded about 2-6 times as compared with plain resulting in addition of DCCA and crystal structures ex-hibited amorphous state. Moreover as increase of water a short gellation time was obtained. The samples added PEG showed increase of specific surface areas up to 20-40% and had micropores while those of Lipase were decreased about 90% and showed broad pore size distribution.

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알루미나-지르코니아 복합체의 제조공정 및 미세구조에 미치는 폴리머 첨가의 영향 (Effect of Polymer Content on Synthesis Process and Microstructure of Alumina-Zirconia Composite)

  • 이상진;권명도;이충효;조경식
    • 한국분말재료학회지
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    • 제10권5호
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    • pp.310-317
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    • 2003
  • Two-component ceramic (alumina-zirconia) composites were fabricated by a soft-solution process in which polyethylene glycol (PEG) was used as a polymeric carrier. Metal salts and PEG were dissolved in ethyl alcohol without any precipitation in 1:1 volume ratio of alumina and zirconia. In the non-aqueous system, the flammable solvent made explosive, exothermic reaction during drying process. The reaction resulted in formation of volume expanded, porous precursor powders by a vigorous decomposition of organic components in the precursor sol. The PEG content affected the grain size of sintered composites as well as the morphology of precursor powders. The difference of microstructure in sintered composite was attribute to the solubility and homogeneity of metal cations in precursor sol. At the optimum amount of the PEG polymer, the metal ions were dispersed effectively in solution and a homogeneous polymeric network was formed. It made less agglomerated particles in the precursor sol and affected on uniform grain size in sintered composite.

고분자 LB막의 유기 가스 감지 특성 (Characteristics of Organic Gas Sensitivity in Polymer LB Films)

  • 신훈규;최용성;권영수;장상목;이범종
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1993년도 추계학술대회 논문집
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    • pp.109-111
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    • 1993
  • We reported the fabrication and thermal cross-linking of the LB files on porous substrates. The monolayers of the polymers which polyion-conplexed with PAA at the air-water interface can be transferred onto solid substrates such as porous fluorocarbon membrane filter and quartz crystal microbalance. The properties of the monolayers and the LB films investigated by $\pi$-A isothem, FT-IR, and SEM will be discussed. In addition, it was attempted to investigate the reaction of polymer LB films in the organic gas surrounding by the use of LB technique.

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상전환법에 의한 미세다공성 한외여과막의 제조 및 투과특성 (Preparation and Permeation Characteristics of Finely Porous Ultrafiltration Membranes by Phase Inversion Method)

  • 홍영기;배기서
    • 한국염색가공학회지
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    • 제15권2호
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    • pp.68-75
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    • 2003
  • In this work, ultrafiltration(UF) membranes were prepared using polyethersulfone(PES). The polymer was dissolved in various solvent, such as N, N-dimethyl formamide(DMF), N,-dimethyl acetamide (DMAc), N,N-dimethyl sulfoxide(DMSO) and N-methyl-2- pynolidone(NMP). Each polymer solution was casted on the glass plate, and immersed into non-solvent bath. In this way finely porous UF membranes were prepared by phase inversion method. The cross sectional structure of PES membrane was asymmetric which was consist of sponge-like sublayer, finger-like toplayer, and active skin layer. From the solute rejection experiments, the molecular weight cut off of the prepared membrane in various solvent was evaluated 10,000 for DMF, 30,000 for DMAc, 50,000 for DMSO, and 10,000 for NMP respectively.

자기치유 부식방지 코팅의 최근 동향 (Self-healing Coatings for Corrosion Protection: A Review of Recent Advances)

  • 박병규
    • 한국표면공학회지
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    • 제47권5호
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    • pp.244-251
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    • 2014
  • In recent years, self-healing coatings have been the subject of increasing interest. The ability of such coatings to self-repair local damage caused by external factors is a major factor contributing to their attractiveness. Metals are extensively used in modern society in a range of applications from infrastructure to aircraft to consumer products. The protection of metals, primarily from corrosion has been an active area of materials science for many years. The aim of this review is the demonstration for recent progress achieved in the development of carrier-based self-healing coatings for the protection of metals. This review mainly covers the reports published after 2010. Two main types of carriers for corrosion inhibitors or healing agents-polymer capsules and porous composite inorganic nanoparticles-are described.