• 제목/요약/키워드: PHR

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Polymer Substrate Materials with Low Dielectric Loss Using Dicyclopentadienyl Bisphenol Cyanate Ester and Polyphenylene Ether (다이사이클로펜타다이에닐 비스페놀 시아네이트 에스터와 폴리페닐렌에테르를 이용한 저유전손실 고분자 기판 소재)

  • Kim, Dong-Kook;Park, Seong-Dae;Lee, Woo-Sung;Yoo, Myong-Jae;Park, Se-Hoon;Lim, Jin-Kyu;Kyoung, Jin-Bum
    • Polymer(Korea)
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    • v.31 no.6
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    • pp.474-478
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    • 2007
  • Polymer substrate materials with low dielectric loss were obtained by fabricating the composite using dicyclopentadienyl bisphenol cyanate ester oligomer and polyphenylene ether (PPE). From the analysis of the curing reaction of oligomer and catalyst, it was observed that the optimum amount of catalyst was 0.02 phr of Zn content. It was applied to the fabrication of polymer composite. By changing oligomer/PPE weight ratio, the peel strength and the gel content of the fabricated composites were measured, and then, the dielectric constant and the dissipation factor were measured in the GHz frequency range. The amount of PPE affected the peel strength and the dielectric properties of composites. However, the amount of catalyst did not affect them at all. Resulting from all experiments, we obtained polymer composite laminates haying the peel strength of above 1 kN/m and the low dissipation factor of 0.004 at 1 GHz.

Organic/inorganic Hybrid Electrolytes for the Application of Direct Methanol Fuel Cell (DMFC) - Preparation and Properties of Sulfonated SEBS (SSEBS)-clay Hybrid Membranes - (직접메탄올 연료전지용 유무기 하이브리드 전해질 - 술폰화된 SEBS (SSEBS)-clay 하이브리드 막의 제조 및 물성 -)

  • Nam Sang Yong;Park Byung-Kil;Kong Sung-Ho;Kim Young Jin
    • Membrane Journal
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    • v.15 no.2
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    • pp.165-174
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    • 2005
  • Sulfonated poly(styrene-ethylene-butadiene-styrene) (SSEBS)-clay hybrid membranes were prepared by solution method. In the preparation of hybrid membrane, the amount of clay content was fixed to 5 phr and montmorillonite (MMT) was fully exfoliated by the SEBS and it was confirmed by X-ray diffraction method. D-spacing of the characteristic peak from MMT plate in WAXD was fully diminished. Gas permeability, mechanical properties and thermal properties of the SSEBS-clay hybrid membranes were investigated. Gas permeability through the SSEBS-clay hybrid membranes decreased due to increased tortuosity made by exfoliation of clay in SEBS.

Mechanical property of Diglycldyl ether of bisphenol A-Methylene dianiline System with Succinonitrile (Diglycidyl ether of bisphenol A-Methylene dianiline-Succinonitrile계의 역학적 성질)

  • Cho, Sung-Woo;Shim, Mi-Ja;Kim, Sang-Wook
    • Korean Journal of Materials Research
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    • v.2 no.3
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    • pp.191-196
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    • 1992
  • The new epoxy resin, diglycidyl ether of bisphenol A(DGEBA)/4, 4'-methylene dianiline (MDA)/succinonitrile system, containing the reactive additive succionitrile was investigated through the impact test and the stress-strain test on the basis of the behavior of cure reaction and the cure mechanism. The new epoxy resin system, having the different succinonitrile contents, were cured at $80^{\circ}C$for 1.5 hour and then in order to cure completely at $150^{\circ}C$ for 1 hour. It was shown that as the succinonitrile content increased, impact strength was gradually increased, tensile strength was decreased, almost constantly Young's modulus was sustained and elongation was increased until the succinonitrile content was increased to 10phr, and then decreased. From the experimental results, it can be concluded that the chemical bonding length between the main chains was extended by adding the reactive additive succinonitrile. It was also found that the flexibility of epoxy resin was improved by adding the succinonitrile.

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Effect of Amino Modified Siloxane on the Properties of Epoxy Composites for MEMS Adhesives (MEMS 접착제용 에폭시 복합재의 아미노 변성 실록산 첨가에 의한 효과)

  • Lee, Donghyun;Yu, Kihwan;Kim, Daeheum
    • Korean Chemical Engineering Research
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    • v.47 no.2
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    • pp.203-207
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    • 2009
  • In the NCAs(non-conductive adhesive) for adhesion of Micro Electro Mechanical System(MEMS), there are some problems such as delamination and cracking, because of the differences of CTE(coefficients of thermal expansion) between NCAs and substrates. Addition of inorganic particle or flexibilizer have been performed to solve those problems. In this study, to improve the flexibility of epoxy adhesive, epoxy/siloxane composites were prepared by adding 1, 3, or 5 phr of amino modified siloxane(AMS). Glass transition temperatures(Tg), moduli and CTE of those composites were measured to confirm effects of siloxane on thermal/mechanical properties of siloxane/epoxy-composites. Tg of AMS/epoxy-composites decreased from $134^{\circ}C$ to $122^{\circ}C$ with increasing AMS contents and moduli decreased from 2,425 MPa to 2,143 MPa with increasing AMS contents. But CTE of AMS/epoxy-composites increased from $67ppm/^{\circ}C$ to $71ppm/^{\circ}C$ with increasing AMS contents. In short, the addition of siloxane is effective for enhancing the flexibility of epoxy but leads to the decrease of Tg.

A Study on Property Change of Acrylic Rubber by Selected Monomers and Crosslinking Agent (선택된 단량체와 가교제에 의한 아크릴고무의 물성 변화에 관한 연구)

  • Kim, Jun-Ho;Cho, Ur-Ryong
    • Elastomers and Composites
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    • v.47 no.1
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    • pp.75-81
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    • 2012
  • Acrylic rubber was synthesized using ethyl acrylate. butyl acrylate, methoxyethyl acrylate as main monomers and glycidyl methacrylate as cure site monomer by emulsion polymerization. Rubber compound was made by adding 2,2-bis[4-(4-aminophenoxy)phenyl]propane as crosslinking agent. Increase of ethyl acrylate content in the main monomer ratio resulted in enhancement of heat resistance due to decrease of glass transition temperature in acrylic rubber. And also oil resistance was increased with increasing content of ethyl acrylate because ethyl acrylate has the highest ester concentration in the three main monomers. With content of 2,2-bis[4-(4-aminophenoxy)phenyl]propane, both tensile strength and elongation were increased until 2 phr, but in higher content than that, they decreased owing to reduction of viscosity and elongation by increase of crosslinking density.

Preparation of Solventless UV Curable Thermally Conductive Pressure Sensitive Adhesives and Their Adhesion Performance

  • Baek, Seung-Suk;Park, Jinhwan;Jang, Su-Hee;Hong, Seheum;Hwang, Seok-Ho
    • Elastomers and Composites
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    • v.52 no.2
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    • pp.136-142
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    • 2017
  • Using various compositions of thermally conductive inorganic fillers with boron nitride (BN) and aluminum oxide ($Al_2O_3$), solventless UV-curable thermally conductive acrylic pressure sensitive adhesives (PSAs) were prepared. The base of the PSAs consists of 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and isobornyl acrylate.The compositions of the thermally conductive inorganic fillers were 10, 15, 20, and 25 phr in case of BN, and 20:0, 15:5, 10:10, 5:15, and 0:20 phr in case of $BN/Al_2O_3$. The adhesion properties like peel strength, shear strength, and probe tack, and the thermal conductivity of the prepared PSAs were investigated with different thermally conductive inorganic filler contents. There were no significant changes in photo-polymerization behavior with increasing BN or $BN/Al_2O_3$ content. Meanwhile, the conversion rate and transmittance of the PSAs decreased and their thermal stabilities increased with increasing BN content. Their adhesion properties were also independent of the BN or $BN/Al_2O_3$ content. The dispersibility of BN in the acrylic PSAs was better than that of $Al_2O_3$ and it ranked the thermal conductivity in the following order: BN > $BN/Al_2O_3$ > $Al_2O_3$.

Reactive blends of poly(butylene terephthalate)/polyamide-6 with ethylene glycidyl methacrylate

  • Han, M.S.;Lim, B.H.;Jung, H. C.;Hyun, J.C.;Kim, S.R.;Kim, W.N.
    • Korea-Australia Rheology Journal
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    • v.13 no.4
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    • pp.169-177
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    • 2001
  • Morphological, thermal, rheological, and mechanical properties of reactive compatabilized blends of poly(butylene terephthalate) (PBT) and Polyamide-6 (PA) containing EGMA copolymer were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), advanced rheometric expansion system (ARES), and universal testing machine (UTM). From the results of thermal analysis by DSC, the melting point of the 30/70 PBT-PA blend was broadened after EGMA was added in the blends, since the enthalpy of melting of the PBT-PA somewhat decreased with the increase of EGMA content. From this result, it is suggested that the EGMA affected to the crystallization behavior and crystallinity of the PBT-PA blends. From SEM micrographs of the 70/30, 50/50, and 30/70 PBT-PA blends, the droplet size of the 30/70 PBT-PA blend was about 0.8 ${\mu}{\textrm}{m}$ which was smaller than that of the 50/50 and 70/30 PBT-PA blends. The complex viscosity of the 30/70 PBT-PA blend observed to be higher than that of the 50/50 and 70/30 PBT-PA blends. From the results of the morphology and rheological properties for the PBT-PA blends, it is suggested that the compatibility is increased in the 30/70 PBT-PA blend than the 50/50 and 70/30 PBT-PA blends. From the results of mechanical properties, it was found that the tensile strength of the 30/70 PBT-PA blend increased with the increase of EGMA up to 2 phr, while tensile strength of the blend in which EGMA content was higher than 2 phr decreased with the increase of EGMA content. From the results of morphological, thermal, rheological, and mechanical properties for the PBT-PA-EGMA blends, it is suggested that the EGMA could be used as a compatibilization role in the blends.

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The Effect of Zirconate Addition on the Joint Properties of Epoxy Adhesive for Car Body Assembly (차체 구조용 에폭시 접착제의 접합부 특성에 미치는 Zirconate 첨가효과)

  • Jeung, Eun-Taek;Lee, Hye-Rim;Lee, So-Jeong;Lim, Chang-Young;Seo, Jong-Dock;Kim, Mok-Soon;Kim, Jun-Ki
    • Journal of Welding and Joining
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    • v.31 no.5
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    • pp.71-76
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    • 2013
  • The effect of zirconate having - NH functional group on the T-peel and lap shear strength of $CaCO_3$ containing structural epoxy adhesive for car body assembly was investigated. Curing behavior of epoxy adhesive samples were investigated by differential scanning calorimeter (DSC) techniques. The addition of zirconate up to 7.5 phr did not affect the curing mechanism of epoxy adhesive. While the small amount of zirconate addition less than 1.1 phr increased the cross-linking density, the excess addition of zirconate resulted in the increase of uncross-linked impurity. From the increase of T-peel and lap shear strength and the change of fracture mode from the adhesive failure to the mixed one, it was considered that the small addition of zirconate was effective in improving the adhesion strength of epoxy adhesive to the adherend and inorganic filler surfaces. The formation of uncross-linked impurity with the excess addition of zirconate was considered to decrease the joint strength by decreasing the cohesive strength of the cured epoxy.

A Study on the Physical Properties of Reinforcing Fillers with Dual Phase Structure (이중상 구조를 가진 보강성 충전제의 물리적 특성 연구)

  • Lee, Seag;Park, Nam Cook
    • Applied Chemistry for Engineering
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    • v.9 no.4
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    • pp.608-613
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    • 1998
  • The purpose of this experiment was the physical properties of rubber compounds with DPCB and pure carbon black. Si-O peak in the silcia surface was observed at the range of wavenumber from 1,100 to 1,200 in the DPCB by FT-IR analysis. Cure rate of rubber compounds containing DPCB and organic silane coupling agent were (Si69) delayed compared with those containing pure carbon black. 300% modulus and interaction coefficient of DPCB with silane coupling agent were higher than those of pure carbon black and PICO weight loss amount showed constant value. It was found that $0^{\circ}C$ tan$\delta$ of rubber compounds with DPCB was larger than those of pure carbon black at 2.0% silane coupling agent based on 50 phr DPCB and $60^{\circ}C$ tan$\delta$ of rubber compounds with DPCB decreased as increasing the usage coupling agent. Consequently, it is postulated that DPCB is strong candidate material for lowering rolling resistance under constant abrasion resistance.

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A Trusted Sharing Model for Patient Records based on Permissioned Blockchain

  • Kim, Kyoung-jin;Hong, Seng-phil
    • Journal of Internet Computing and Services
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    • v.18 no.6
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    • pp.75-84
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    • 2017
  • As there has been growing interests in PHR-based personalized health management project, various institutions recently explore safe methods of recording personal medical and health information. In particular, innovative medical solution can be realized when medical researchers and medical service institutes can generally get access to patient data. As EMR data is extremely sensitive, there has been no progress in clinical information exchange. Moreover, patients cannot get access to their own health data and exchange it with researchers or service institutions. It can be operated in terms of technology, yet policy environment are affected by state laws as well as Privacy and Security Policy. Blockchain technology-independent, in transaction, and under test-is introduced in the medical industry in order to settle these problems. In other words, medical organizations can grant preliminary approval on patient information exchange by using the safely encrypted and distributed Blockchain ledger and can be managed independently and completely by individuals. More apparently, medical researchers can gain access to information, thereby contributing to the scientific advance in rare diseases or minor groups in the world. In this paper, we focused on how to manage personal medical information and its protective use and proposes medical treatment exchange system for patients based on a permissioned Blockchain network for the safe PHR operation. Trusted Model for Sharing Medical Data (TMSMD), that is proposed model, is based on exchanging information as patients rely on hospitals as well as among hospitals. And introduce medical treatment exchange system for patients based on a permissioned Blockchain network. This system is a model that encrypts and records patients' medical information by using this permissioned Blockchain and further enhances the security due to its restricted counterfeit. This provides service to share medical information uploaded on the permissioned Blockchain to approved users through role-based access control. In addition, this paper presents methods with smart contracts if medical institutions request patient information complying with domestic laws by using the distributed Blockchain ledger and eventually granting preliminary approval for sharing information. This service will provide an independent information transaction and the Blockchain technology under test will be adopted in the medical industry.