• Title/Summary/Keyword: silicone

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Status and Prospect of Test Methods of Quality Silicone Water Repellent for Protecting Reinforced Concrete

  • Sun, H.Y.;Yuan, Z.Y.;Yang, Z.;Shan, G.L.;Shen, M.X.
    • Corrosion Science and Technology
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    • v.16 no.3
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    • pp.141-150
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    • 2017
  • Impregnating with quality silicone water repellent on the concrete surface is an effective method of protecting concrete. Quality silicone water repellent has been widely used in the engineering profession because of its desirable properties such as hydrophobicity, keeping concrete breathable and preserving the original appearance of the concrete. The companies in China that produce silicone water repellent are listed. Test methods in the specifications or standards about silicone water repellent in China are summed. The test methods relative to durability of concrete impregnated with silicone water repellent (such as resistant to chloride ion penetration, resistant to alkali, resistance to freezing and thawing and weatherability etc.) and the constructive quality (such as water absorption rate, impregnating depth and the dry velocity coefficient etc.) are compared and analyzed. The results indicate that there are differences among test methods relative to different specifications with the same index and therefore, confusion has ensued when selecting test methods. All test methods with the exception of the method of water absorption rate by using a Karsten flask are not non-destructive methods or conducted in a laboratory. Finally, further research on silicone water repellent during application is proposed.

Finite Element Analysis of Residual Stress Evolution during Cure Process of Silicone Resin for High-power LED Encapsulant (고출력 LED 인캡슐런트용 실리콘 레진의 경화공정중 잔류응력 발달에 대한 유한요소해석)

  • Song, Min-Jae;Kim, Heung-Kyu;Kang, Jeong-Jin;Kim, Kwon-Hee
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.2
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    • pp.219-225
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    • 2011
  • Silicone resin is recently used as encapsulant for high-power LED module due to its excellent thermal and optical properties. In the present investigation, finite element analysis of cure process was attempted to examine residual stress evolution behavior during silicone resin cure process which is composed of chemical curing and post-cooling. To model chemical curing of silicone, a cure kinetics equation was evaluated based on the measurement by differential scanning calorimeter. The evolutions of elastic modulus and chemical shrinkage during cure process were assumed as a function of the degree of cure to examine their effect on residual stress evolution. Finite element predictions showed how residual stress in cured silicone resin can be affected by elastic modulus and chemical shrinkage behavior. Finite element analysis is supposed to be utilized to select appropriate silicone resin or to design optimum cure process which brings about a minimum residual stress in encapsulant silicone resin.

Acute Pulmonary Embolism by Silicone Injection: Radiologic Findings (실리콘액 주사에 의한 급성 폐색전증: 영상의학적 소견)

  • Lee, Jae-Kyo
    • Journal of Yeungnam Medical Science
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    • v.21 no.2
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    • pp.215-223
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    • 2004
  • Silicone is widely used for medical purposes in breast augmentation and other cosmetic procedures. Illegal injections of silicone in human beings might have adverse effects and one of the serious problems is a silicone embolism. We experienced five cases of unusual respiratory difficulties after an injection of liquid silicone in the breast, vagina, uterus, and hip. They were all young adult females, who were previously healthy. One of them died after the injection. The three remaining patients were admitted because of dyspnea, coughing, chest discomfort and bilateral pulmonary infiltration after the silicone injection. A transbronchial lung biopsy and autopsy disclosed many oil like materials filling the alveolar septal capillaries. Three patients underwent a computed tomogram (CT), which revealed multifocal airspace consolidations at the peripheral and nondependent portions of both lungs, which is a different finding from other thromboembolisms. Lung scans of the disclosed abnormalities were compatible with silicone induced pulmonary embolism.

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The surface discharge performance of silicone rubber in the Salt fog test (Salt fog 시험에서 silicone rubber에서 발생하는 방전 전류의 특성)

  • 강성화;박영국;이광우;김완수;이용회
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.565-569
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    • 1999
  • In these days, the silicone insulators have been increasingly studied and applied for outdoor insulators because it has superior characteristics than porcelain and glass insulators, which have been used for outdoor insulators. First of all, The excellent performance of the silicone rubber in polluted and wet conditions is attributed to the ability of the material to maintain the hydrophobicity of the surface in the presence of severe contamination and wet conditions. This is because of the presence of low molecular weight mobile fluid in the silicone rubber which diffuses to the surface and to above the contamination layer. But, the leakage current and some surface discharge occurs on surface of the composite polymeric insulation materials when the insulator is used for a long time with severe contaminative condition and it can lead the contamination flashover. So the leakage current and the discharge current are important to estimate the condition of the silicone rubber surface. In this paper, the average leakage current, the relation of surface discharge current and phase angle were study to investigate electrical conduction of silicone rubber surface with the salt fog condition.

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Analysis of Physical Performance, Hygiene and Safety of Silicone-Laminated Stretch Material (실리콘이 라미네이팅된 신축성 소재의 위생 및 안전성과 역학적 성능)

  • Kwon, Myoung-Sook;Jung, Gi-Soo
    • Journal of the Korean Society of Clothing and Textiles
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    • v.31 no.1 s.160
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    • pp.77-84
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    • 2007
  • The purpose of this study was to investigate and to compare the performances of silicone laminated materials sold for swimming cap in market, to get the basic data for product development. We selected 4 specimens and tested their air permeability, waterproofness and breathability. We also tested the physical and mechanical properties of the specimens using KES system. Silicone-laminated material was not bursted on high hydraulic pressure since silicone membrane gave waterproofness while PU/Polyester substrate gave elasticity. It didn't have air permeability and breathability at all. Any toxic materials such as Formaldehyde, Deldrin, PCP, Amin, TDBPP were not detected in silicone-laminated material and other materials. Silicone-laminated material had higher stretchability with the low force but it had lower elastic recovery and shape stability comparing to PU laminated material. It had lower flexibility than PU laminated material. It had lower unrecoverable amount in shearing direction. Friction coefficient was higher in silicone-laminated material than PU laminated material due to its surface stickiness. It was compressed easily and its compression resiliency was higher with compared to PU laminated material.

The Electrical Properties of High Voltage Silicone Rubber (고전압용 실리콘고무의 전기적 특성)

  • 김성필;송정우;이종필;이수원;김왕곤;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.779-782
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    • 2000
  • Silicone rubbers are first silicone polymers and has named silicone from existence of Si-O bond similar to Keton. Silicon in organic compound has been called silicone, and linear or network polymers. Silicone rubbers have been used as an power insulator because they are well weather proof, ozone proof and have excellent electric characteristics, thermal stability, cold resistance and low surface energy. Especially, it is known that they have very excellent characteristics at 200[$^{\circ}C$]. For this study, we made silicone rubbers as specimens and we measured dielectric loss tangent due to applied voltage at temperature range 25[$^{\circ}C$] to 180[$^{\circ}C$] and frequency range 20[Hz] to 1${\times}$10$\^$6/[Hz] to examine dielectric properties. We measured dielectric loss tangent to study the insulation performance of silicone rubbers.

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Preparation of Silicone Rubber Membrane and its Porosity (Silicone Rubber Membrane의 제조 및 기공특성)

  • Lee, Seung-Bum;Kim, Hyung-Jin;Hong, In-Kwon
    • Elastomers and Composites
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    • v.30 no.3
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    • pp.185-194
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    • 1995
  • Membrane process has been employed to separate a specific substance from gas or liquid mixture, and treat wastewater. This is due to the fact that the substance of mixture can be permeated and separated selectively by membrane. Since Initial equipment and operation costs are not expensive, membrane process has been adopted in various fields such as petroleum Industry, chemistry, polymer, electronics, foods, biochemical industry and wastewater treatment. In this study, $CaCO_3$ particles impregnated in silicone rubber network were extracted by using supercritical carbon dioxide and pore distribution of silicone $rubber-CaCO_3$ was investigated with varying amount of extract. Silicone rubber has excellent mechanical properties such as heat-resistance, cold-resistance etc. and $CaCO_3$ has microporous structure. It is possible to make silicone $rubber-CaCO_3$ composite sheets via work-intensive kneading processes. In so doing $CaCO_3$ particles become distributed and impregnated in silicone rubber network. Supercritical carbon dioxide diffuse through composite sample, then sample is swollen. $CaCO_3$ in silicone rubber network Is dissolved in supercritical carbon dioxide, and its sites become pores. Pore distribution, pore shape and surface area are observed by SEM(scanning electron microscope) micrograph and BET surface area analyzer examination respectively. Pore characteristics of membrane suggest the possibilities that the membrane can be used for process of mixture separation and wastewater treatment.

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Physical Properties of Cotton Fabric Treated with BTCA and P olyalkyleneoxide-modified amino-functional silicone (BTCA와 실리콘 처리 면직물의 물리적 성질)

  • 남승현;유효선
    • Journal of the Korean Society of Clothing and Textiles
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    • v.22 no.4
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    • pp.525-534
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    • 1998
  • Cotton fabrics were finished with mixture of BTCA(1,2,3,4,-butanetetracarboxylic acid) and polyalkyleneoxide-modified amino-functional silicone by pad-dry-cure process to achieve better DP performance with a higher retention of physical properties as compared to those of finished with BTCA alone. The results indicated that BTCA improved the wrinkle recovery but reduced significantly the tensile and tear strength of the treated fabrics. Whereas silicone imparted a lower wrinkle recovery, a lower loss of tensile strength than BTCA, in addition improved considerably the tear strength owing to reduction in inter-fiber and/or inter-yarn frictional forces. The concentration and curing temperature needed to enhance physical properties were as follows; for BTCA treatments 6%, at 18$0^{\circ}C$, for silicone treatments 1% at 14$0^{\circ}C$. This optimum concentration of silicone was observed by using the mixture of BTCA and silicone. The wrinkle recovery and DP rating of cotton fabrics treated with mixture of 4% BTCA and 1% silicone at a curing temperature of 17$0^{\circ}C$ was similar to those of treated with 6% BTCA at a curing temperature of 18$0^{\circ}C$, and other performance properties observed were; an increase in tensile strength, extension, toughness, abrasion resistance and moisture regain due to the reduction of BTCA concentration and curing temperature, futhermore an improvement in bending and surface properties due to the lubricating effect of silicone. On the other hand 1% aqueous silicone solution showed the lowest surface tension. Such nonionic surface activity resulted in a more uniform and rapid deposition of BTCA on the fiber or fabric.

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Development of Cannula-typed Silicone Voice Prosthesis(So-Mang$\circledR$) (Cannula-typed Silicone Voice Prosthesis(소망$\circledR$)의 개발)

  • 최홍식;정은주;전희선;문인석;김영호;김광문
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.12 no.2
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    • pp.152-157
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    • 2001
  • Background : Electrolarynx, Esophageal voice, and Silicone voice prosthesis with tracheoesophageal(T-E) fistula have been used as vocal rehabilitating methods for the post-laryngectomized patients. Prosthetic rehabilitation of voice after total laryngectomy has gained wide acceptance and has become a common practice in many clinics since the pioneering works of Singer and Blom In 1979. Since the introduction of tracheo-esophageal puncture and application of Blom Singer$\circledR$ voice prosthesis in 1980, several reliable voice prostheses have been developed and are successfully being used. Objectives : Even though quality of voice produced by Silicone voice prosthesis with T-E fistula is superior to other modalities, it still has some disadvantages. We devised a new cannulatyped silicone voice prosthesis. Methods : 1) Devising a new prototype of cannula-typed silicone voice prosthesis. 2) Application of the prototype using canine animal model(laryngectormized dog) and fitting trial on human patient whose previously inserted Silicone voice prosthesis is not functioning due to presumed fungal infection. Discussion : Final form of prototype was made after several times of major and minor modifications. Insertion of the newly developed Cannula-typed Silicone voice prosthesis on canine animal model and human trial were done without any difficulty. There were no serious leakage of saliva or food during swallowing. Conclusion : The newly developed Cannula-typed Silicone voice prosthesis(So-Mang$\circledR$) and the modified replacement method will further improve the results of post-laryngectomized prosthetic voice rehabilitation. Long-term animal study and human trial are planned in the near future.

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A Study on the Resin Finishing of Silk Fabric -Silicone Resin Finishing- (견직물의 수지가공에 관한 연구)

  • 남중희;탁태문
    • Journal of Sericultural and Entomological Science
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    • v.27 no.2
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    • pp.28-39
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    • 1985
  • The structural and useful characteristics of silk habutae treated with silicone resin by emulsion finishing method were studied. The results were obtained through crease recovery test, water repellency test, scanning micrograph observation, amino acid analysis, X-Ray diffraction analysis, and Fourier Transform Infrared Spectroscopy. The results are summarized as follows; 1) The improvement in crease recovery of silk habutae finished with silicone resin, was observed b soaping treatment and curing conditions. 2) The higher water repellency and stiffness in silk fabrics finished with silicone resin was found by the fabric inspection and the scanning electron microscopic observation. It is suggested that silicone resin impregnated into the void of silk fibroin. 3) The polar side chains of amino acid composition were decreased, when the silicone resin was treated on silk fibroin. 4) Through Amino acid analysis of silicone resin finished fibroin, the different amounts of amino acid composition was indicated due to silk fibroin silicone polymer reaction and the structural difference of its fibroin were also proved by X-ray diffractograms. 5) The functionality of the siloxane compound may be deduced from the silicone finished silk habutae by Fourier Transform Spectroscopy. It was concluded from the above results that the useful characteristics of silk fabric can be improved by silicone resin finishing.

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