• Title/Summary/Keyword: durability polymer film

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Comparison of Durability for PUA Type Resin using Wear and Nano-indentation Test (마모 및 나노 압입 시험을 이용한 PUA계 레진의 내구성 비교)

  • Choi, Hyun Min;Kwon, Sin;Jung, Yoon-Gyo;Cho, Young Tae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.5
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    • pp.8-15
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    • 2018
  • Films with special properties (e.g., water-repellent films, optical films, anti-reflection films, and flexible films) are referred to as functional films. Recently, there has been interest in fine patterning methods for film fabrication. In particular there have been many studies that use a UV nanoimprint process involving a UV curing method. In this paper, a polymer film was fabricated by the UV nanoimprint process with a micro-pattern, and its durability was evaluated by a wear test and a nano-indentation test. The film mechanical properties (such as coefficient of friction, hardness, and modulus of elasticity) were measured. Moreover, the choice of PUA type resin used in the UV nanoimprint process was confirmed to impact the durability of the thin film. Despite making the polymer film samples using the same method and PUA type resin, different coefficient of friction, hardness, and modulus of elasticity values were obtained. PUA 4 resin had the most favorable coefficient of friction, hardness, and modulus of elasticity. This material is predicted to produce a high durability functional film.

Studies on Durability and Polarization Properties of Poly(vinyl alcohol) Polarizing Films Prepared with Reactive Dichroic Dyes (반응성 이색성 염료를 사용하여 제조한 폴리(비닐 알코올) 편광필름의 내구성 및 편광특성에 관한 연구)

  • Choi, E-Joon;Choi, Seung Sock;Park, Il Hyun;Chang, Jin Ho;Back, Sang-Hyun;Park, Sang-Bong
    • Polymer(Korea)
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    • v.37 no.1
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    • pp.66-73
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    • 2013
  • Three reactive dichroic dyes with 3,5-dichloro-2,4,6-triazine moiety were synthesized by reaction between dichroic dyes (such as congo red, direct black 22 or direct black 4) and cyanuric chloride. Poly(vinyl alcohol) (PVA) films were dyed with the obtained three reactive dichroic dyes. After 400% drawing of the PVA films, their optical properties were compared with an iodine-doped PVA film prepared in the same condition. Durability test was performed at $50^{\circ}C$ in 85% of relative humidity for 120 hrs. We found that compared with the iodine-doped PVA polarizing film, the relative durability of the PVA polarizing film dyed with the reactive dichroic dyes was greatly improved.

Preparation and Polarization Properties of Poly(vinyl alcohol) Polarizing Film Using the Mixed System of Supercritical $CO_2$/Organic Solvents/Dichroic Dye (초임계 탄산가스/유기용매/이색성 염료의 혼합계를 이용한 폴리(비닐 알코올) 편광필름의 제조 및 편광특성)

  • Park, Ki-Sang;Choi, E-Joon;Chang, Jin-Ho;Park, Il-Hyun
    • Polymer(Korea)
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    • v.35 no.5
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    • pp.458-466
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    • 2011
  • In the mixed system of supercritical carbon dioxide/organic solvents, poly(vinyl alcohol)(PVA) film of high degree of hydrolysis could be dyed with a dichroic dye of C. I. direct black 22(DB22) and as a result, high durability was obtained. Especially, as a dye dispersant in a supercritical fluid phase, a mixed solvent system of ethylene glycol: dimethyl sulfoxide=4 : 6 weight ratio was investigated. Then the optimum pressure for dyeing could be reduced down to 200 bar. Using this supercritical fluid system, the maximum dyeing appeared as the transmittance of less than 1% and the waste amount was reduced to the level of 1/10. After 500% drawing of this PVA film, both the polarizing efficiency of 94% and the single piece transmittance of 30% were obtained. The limitation of DB22 and further improvements were also discussed.

Durability of Polymers for Cement Modifier in Autoclave Cure (오토클래이브양생에 의한 시멘트 혼화용 폴리머의 내구성)

  • Joo, Myung-Ki;Lee, Youn-Su
    • Journal of the Korea Concrete Institute
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    • v.15 no.6
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    • pp.888-893
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    • 2003
  • The purpose of this study is to make clear the durability of the polymer films formed in the autoclaved polymer-modified mortars and concretes. The polymer films prepared with polymer dispersions such as a styrene-butadiene rubber (SBR) latex, a poly (ethylene-vinyl acetate)(EVA) emulsion and a polyacrylic ester (PAE) emulsion for polymeric admixtures are exposed to autoclaving at 18$0^{\circ}C$ in temperature and 1.01 MPa in vapor pressure, and subjected to tensile test and infrared spectroscopy. The durability of the polymer films is evaluated from the application of autoclaving to the polymer films under saturated Ca(OH)$_2$ solution immersion causes no degradation for SBR films and a significant degradation due to the saponification of the polymers for EVA and PAE films. Accordingly, in the application of autoclaving to polymer-modified mortars and concretes, it is suggested that SBR-modified mortars and concretes are hardly degraded but EVA- and PAE-modified mortars and concretes are markedly degraded by the saponification of the polymers.

Perfluorinated Sulfonic Acid Ionomer-PTFE Pore-filling Membranes for Polymer Electrolyte Membrane Fuel Cells (고분자전해질연료전지용 과불소계 술폰화 이오노머-PTFE 강화막)

  • Kang, Seong Eun;Lee, Chang Hyun
    • Membrane Journal
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    • v.25 no.2
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    • pp.171-179
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    • 2015
  • Perfluorinated sulfonic acid ionomers (PFSAs) have been widely as solid electrolyte materials for polymer electrolyte membrane fuel cells, since they exhibit excellent chemical durability under their harsh application conditions as well as good proton conductivity. Even PFSA materials, however, suffer from physical failures associated with repeated membrane swelling and deswelling, resulting in fairly reduced electrochemical lifetime. In this study, pore-filling membranes are prepared by impregnating a Nafion ionomer into the pore of a porous PTFE support film and their fundamental characteristics are evaluated. The developed pore-filling membranes exhibit extremely high proton conductivity of about $0.5S\;cm^{-1}@90^{\circ}C$ in liquid water.

A Study on the Anti-Stiction Coating of Glass Lens Mold for Optical Communication (광통신용 글라스렌즈 성형 금형의 이형성 코팅에 관한 연구)

  • Jeong, Woon-Jo;Cho, Jae-Cheol
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.6
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    • pp.962-967
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    • 2017
  • The Diamond-Like-Carbon (DLC) coating is a new carbon-based amorphous material. Carbon ions in the plasma are electrically accelerated and collide with the substrate to form a thin film. This film has similar properties to diamonds such as high surface hardness, low coefficient of friction, corrosion resistance and durability that do not react with acids and bases. Also, since there is no thermal deformation, it can be printed at room temperature. and coated on almost all materials such as paper, polymer, ceramics and various metals even aspheric lens it is possible to mirror surface coating with excellent surface roughness. In this paper, we have analyzed the DLC film formed by Filtered Arc Ion Plating (Filtered AIP) process.

Preparation and Properties of Polymer Blends Type Humidity Sensor for Process Safety (공정안전용 Polymer Blend형 습도센서의 특성 연구)

  • Kang Young-Goo;Cho Myoung-Ho
    • Journal of the Korean Society of Safety
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    • v.19 no.3 s.67
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    • pp.51-56
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    • 2004
  • Conductive polymer blends and composites are widely used for different safety application such as electrostatic charge dissipation(ESD), electromagnetic interference(EMI) shielding, electrostatic prevention and safety chemical sensor. In order to prepare a impedance-type humidity sensor that is durable at high humidities and high temperature, electically conductive polymer blends based on diallyldimethylammonium chloride(DADMAC) and epoxy were prepared in this study. The polymer blends type conductive ionomer exhibits reaction each other DADMAC and epoxy in FT-IR and DSC analysis. The blends material was traced by new peak at 1600cm-1 and appeard improvement of thermal resistance by melting point shift. Alumina substrate was deposited a pair of gold electrodes by screen printing. The blend material were spin-coated with a thin film type on the surface of alumina substrate. The polymer bleld type sensor exhibits a linear impedance increasing better than DADMAC coated humidity sensor. Also it shows good sensitivity, low hysteresis and durability against high humidity.

A Study on the Evaluation of Hydrodynamic Performance of Trileaflet Prosthetic Heart Valves (삼엽식 인공판막의 수력학적 성능평가에 관한 연구)

  • 김혁필;이계한
    • Journal of Biomedical Engineering Research
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    • v.18 no.2
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    • pp.147-156
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    • 1997
  • Various prosthetic heart valves have been developed and used clinically, but they have problems, such as thrombogenecity, hemoltsis, high cost and low durability. New types of trileaflet polymer heart valves have been developed in order to use them as inlet and outlet valves in a ventricular assist device. The aim of this study is to determine the hydrodynamic effectiveness of the newly designed trileaflet polymer valves and their feasibility for temporary use in the blood pumps. Trileaflet polymer valves are made of polyurethane, because of its good blood compatibility, high tonsil strength and good resistance to fatigue. An in vitro experimental investigation was perf'ormed in order to ev91ua1e hydrodynamic performance of the trileaflet polymer valves having different design and fabrication tech- niques. The St. Jude Medical valve (SJMV) and floating-type monoleaflet polymer valve (MLPV) were also tested The pressure drop across the valve, leakage volume, and the flow patterns mere investigated for valves. The result of comparative tests showed that the trileaflet polymer valves had a better hydrodynamic performance than the others. TPV which has two stable membrane shape showed the lowest back flow. The pressure hops of TPVs were lower than that of MLPV, but slightly higher than SJMV. The hydrodynamic performance of valves under the pulastile flow showed the similar results as steady flow. The velocity profiles and turbulent intensities were measured at the distal sites of valves using a hot-film anemometer. Central flow was maintained in trileaflet polymer valves, and the maximum turbulent intensities were lower in TPVs comparing to MLPV.

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Improved Coating of PEDOT : PSS onto CVD Graphene by the Addition of PVA (PVA의 첨가에 의한 CVD 그래핀상 PEDOT : PSS의 코팅성 향상)

  • Park, Min Ui;Shin, Chaeyeon;Kim, Hyeji;Kim, Seung Yeon;Choi, Young Ju;Chung, Dae-won
    • Applied Chemistry for Engineering
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    • v.29 no.6
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    • pp.734-739
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    • 2018
  • We successfully coated poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS) on CVD graphene by adding poly(vinyl alcohol) (PVA) to PEDOT : PSS. Extensive studies on the wettability of coating solutions and electrical properties of formed films led us to conclude that PVA with 89% of the degree of saponification and the molecular weight of less than $100,000gmol^{-1}$ produced optimum results. Furthermore, the optimum content of PVA was found to be 5% of PEDOT : PSS by the solid weight. The film coated by PEDOT : PSS with PVA on CVD graphene displayed a conspicuous improvement in the surface roughness, adhesive property, bending durability and stability in resistance at $160^{\circ}C$, compared to those of using CVD graphene films.

Fabrication of nanoporous ceramic membrane for water treatment (수처리용 나노스케일 다공성 세라믹 멤브레인 제조)

  • Han, Hyuk Su;Lee, Ho Jun;Ryu, Jeong Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.2
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    • pp.77-81
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    • 2019
  • Recently, as the problem of environmental pollution emerges, various methods of eco-friendly water treatment method are being developed. Polymer membranes, which are currently leading the market, are inexpensive, but have many problems in terms of chemical resistance and durability. Thus, ceramic membrane has been attracted great attention as high-efficiency water treatment due to excellent durability and chemical resistant. In this study, ceramic membranes were developed via pore structure, size control, and surface treatment. The pore size of the membrane was controlled through the formation of $ZrO_2$ and $TiO_2$ coating films. Tape casting and sol-gel process were used to form a ceramic coating film with nanopores on the surface of the membrane. Microstructure analysis of ceramic membrane and pore size analysis of the coating film were conducted and the change of water treatment characteristics was observed.