• Title/Summary/Keyword: PHR

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Magnetorheological Elastomer Based on Reactive Blend of Maleic Anhydride Grafted Chloroprene Rubber and Epoxidized Natural Rubber (말레무수물로 개질된 클로로프렌 고무와 에폭시화 천연고무의 반응 블렌드에 기초한 자기유변 탄성체)

  • Choi, Jinyoung;Chung, Kyungho
    • Elastomers and Composites
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    • v.49 no.4
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    • pp.267-274
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    • 2014
  • Self vulcanizable blend system for magnetorheological elastomer (MRE) has been studied by dispersing magneto responsible particle (MRP) on elastomeric matrix. Chloroprene rubber was modified with maleic anhydride (MAH) using heat and pressure which is called dynamic maleation process. The optimum graft ratio of MAH was found at 10 phr contents and reaction temperature of $100^{\circ}C$. This could be confirmed by FT-IR analysis. Epoxided natural rubber (ENR) was blended with modified CR-g-MAH for self vulcanization. The optimum amounts of ENR was 30 wt% in terms of scorch time and curing rate. MRE was manufactured by electromagnetic equipment and orientation of MRE was confirmed by SEM. Finally, it was found that the tensile strength of anisotropic-MRE was higher than that of isotropic-MRE and the hardness was reverse.

Effect of Compatibilizer Types on the Properties of Linear PPS/PET Blends (상용화제의 종류가 선형 PPS/PET 블렌드의 물성에 미치는 영향)

  • Kim, Sungki;Hong, In-Kwon;Lee, Sangmook
    • Polymer(Korea)
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    • v.37 no.4
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    • pp.500-506
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    • 2013
  • The effect of compatibilizer types on the properties of polyphenylene sulfide (PPS)/polyethylene terephthalate (PET) blends was investigated. The blends were extruded by a single screw extruder attached with a Maddock mixing zone and their molded properties were examined. As a basic blend composition, a linear PPS/PET (40/60) blend was selected based on cost efficiency. Three types of compatibilizer, SEBS, modified SEBS, and modified PS were added to the basic blend to improve the properties. The thermal, rheological, mechanical properties and the morphology of the ternary blends were analyzed. The maximum mechanical properties of blends was found at 1 phr of m-SEBS or m-PS content, whose values were almost the same as the theoretical values of miscible blend system. It seemed to by the case that the partial reaction between compatibilizer and the basic blend caused the enhancement of compatibility between linear PPS and PET phases. These ternary blends would be applicable as economic linear PPS alloys.

Personal Health Record/Electronic Medical Record Data Trading Model for Medical My Data Environments (마이데이터 환경에서 개인의 전자 건강/의료 데이터 활용을 위한 데이터 거래모델)

  • Oh, Hyeon-Taek;Yang, Jin-Hong
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.13 no.3
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    • pp.250-261
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    • 2020
  • Today, data subjects should be considered to utilize various personal data. To support this paradigm, the concept of "My Data" has proposed and has realized in various industrial sectors, including medial sectors. Based on the concept of the medical My Data, this paper proposes a personal health record (PHR) and an electronic medical record (EMR) data trading model. Particularly, this paper proposes a system model to support the medical My Data environment and relevant procedure among stakeholders for PHR/EMR data trading that ensures the rights of data subjects. Based on the proposed system model, this paper also proposes various mathematical models to analyze the behavior of stakeholders and shows the feasibility of the proposed data trading model that satisfies the requirements of both data subjects and data consumers.

Effects of Nano-Sized Inorganic Fillers on Polymerization and Thermal Degradation of Polyurethane Composites (나노사이즈 무기분말이 폴리우레탄복합체의 중합 및 열분해반응에 미치는 영향)

  • Lee, Joon-Man;Ahn, Won-Sool
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.3
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    • pp.1027-1034
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    • 2010
  • Effects of inorganic nano-powders on the polymerization and thermal degradation kinetics as well as the mechanical properties of polyurethane nano-composites were studied by both the measurement of polymerization temperature as a function of time and non-isothermal thermogravimetric analysis (TGA) as well as the Instron test. As the results from polymerization studies, the reaction rates of MMT-filled PU composites were faster than those of Ce500-filled ones, and moreover, the activation energies using Kissinger method for the thermal degradation of composites were calculated as 139.34 kJ/mol for the Ce500-filled PU composites and 91.12 kJ/mol for MMT-filled one, respectivel, exhibiting that MMT nano-powder seemed to be acting as the catalyst for both polymerization and degradation of PU composites. UTM result, however, showed that tensile strength at break of MMT-filled composites was much higher than that of Ce500-filled ones above the concentrations range of 5 phr in the composites.

Improvement of Toughness of Tetrafunctional Epoxy (TGDDM) Resin Using Polyamideimide (PAI) Resin (폴리아미드이미드 수지를 이용한 4관능성 에폭시 수지의 강인화 향상)

  • 박수진;허건영;이재락;홍영택;최길영
    • Polymer(Korea)
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    • v.26 no.5
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    • pp.599-606
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    • 2002
  • In this study, 4,4'-tetraglycidyl diaminodiphenyl methane (TGDDM)/polyamideimide (PAI) blends were cured using diaminodiphenyl sulfone (DDS). And the effect of addition of different PAI contents to neat TGDDM was investigated in the thermal, mechanical, and morphological properties of the blends. The cure behavior and thermal stability of the cured specimens were monitored by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. Also, the critical stress intensity factor (K$\_$IC/) was measured in UTM, and the phase separation behavior and final morphology of TGDDM/PAI blends were examined in scanning electron microscopy(SEM). As a result, the cure temperature and cure activation energy (E$\_$a/) were decreased with increasing the PAI content. The decreasing of cure temperature and cure activation energy were probably due to the presence of secondary amine group of PAI backbone used as co-initiator. But, the decomposition activation energy (E$\_$t/) and K$\_$IC/ value were increased up to 5. 10 phr of PAI content, respectively and they were decreased above the PAI contents. These results were explained on the basis of chain scission reaction by etherification. And morphology of blends observed from SEM was confirmed in co-continuous structures.

Vulcanization Efficiency of Non-polar Rubber Compounds by Microwave (마이크로파를 이용한 비극성 고무컴파운드의 가황 효율)

  • Jung, U-Sun;Lee, Won-Ki;Lim, Kwon-Tack
    • Polymer(Korea)
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    • v.35 no.3
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    • pp.228-231
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    • 2011
  • The rate of vulcanization of nonpolar ethylene-propylene-diene terpolymer(EPDM)/carbon black compounds was investigated by using hot air and microwave as a heating source. The present study parameters such as heating source, sample thickness, and loading of an additive. The compound thickness was the main factor in the hot air vulcanization. It was due to the poor thermal conductivity of EPDM; that is, the thicker thickness, the lower vulcanization rate. For 100% vulcanization, the compound with 3 mm thickness required 7 min at $250^{\circ}C$ in the hot air system. However, the vulcanization of EPDM compounds by microwave system was not affected by the thickness while strongly dependent on the amount of a polar additive, carbon black. A compound with 80 phr of carbon black was perfectly vulcanized within 30 sec. These results suggest that the use of microwave as a heating source is an effective method for the vulcanization of compounds including a polar component.

Rubber Compounds with High Gas Barrier Property by Mixing Nylon 6 to Maleic Anhydride Grafted ENR 50 (무수 말레인산으로 그래프트된 ENR 50에 Nylon 6를 혼합한 기체 고차단성 고무 배합물)

  • Lim, Jong Hyuk;Cho, Ur Ryong
    • Polymer(Korea)
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    • v.37 no.6
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    • pp.770-776
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    • 2013
  • The ENR 50 having the lowest gas permeability was blended with Nylon 6 which exhibits superior gas permeability, excellent wear resistance by using a twin-screw extruder. The blended materials showed the increased gas barrier property and physical properties, but did not yield a great synergistic effect due to low dispersion of Nylon 6 to ENR 50. To improve dispersion of Nylon 6 in the rubber matrix, maleic anhydride (MAH) was grafted to ENR 50. The grafting reaction between MAH and ENR 50 was evidenced using IR spectroscopy. The grafted and blended materials, ENR 50- g-MAH/Nylon 6 compounds, resulted in an enhanced gas barrier property and physical properties compared with compounds without MAH. The compound at 5 phr of MAH showed the highest crosslinking density and the best performances.

Effects of Oxygen Plasma-treated Graphene Oxide on Mechanical Properties of PMMA/Aluminum Hydroxide Composites (산소 플라즈마 처리된 그래핀 산화물이 PMMA/수산화알루미늄 컴포지트의 기계적 물성에 미치는 영향)

  • Kim, Hyo-Chul;Jeon, Son-Yeo;Kim, Hyung-Il;Choi, Ho-Suk;Hong, Min-Hyuk;Choi, Ki-Seop
    • Polymer(Korea)
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    • v.35 no.6
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    • pp.565-573
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    • 2011
  • The nanocomposites containing graphene oxide (GO) were prepared in order to improve the mechanical properties of poly(methyl methacrylate)/aluminum hydroxide (PMMA/AH) composites. GO was prepared from graphite by oxidation of Hummers method followed by exfoliation with thermal treatment. The surface of GO was modified by oxygen plasma in various exposure times from 0 to 70 min to improve interfacial compatibility. Compared with PMMA/AH composites, the nanocomposites containing GO modified with oxygen plasma for the exposure time up to 50 min showed significant increases in flexural strength, flexural modulus, Rockwell hardness, Barcol hardness, and Izod impact strength. The morphology of fracture surface showed an improved interfacial adhesion between PMMA/AH composites and GO, which was properly treated with oxygen plasma. The mechanical properties of nanocomposites were deteriorated by increasing the content of GO above 0.07 phr due to the nonuniform dispersion of GO.

Flame Retardancy and Physical Properties of Polyurethane Foam with Expandable Graphite (팽창 흑연을 포함한 폴리우레탄 폼의 난연 및 물성 변화 연구)

  • Bae, Sung-Jun;Park, Ji-Hyeon;Go, Jae-Wang;Choi, Pil-Jun;Lee, Jae-Yeon;Sur, Suk-Hun
    • Journal of Adhesion and Interface
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    • v.20 no.3
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    • pp.96-101
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    • 2019
  • In this study, the flame retardant and physical properties of the expandable graphite/polyurethane foam composites were considered by the addition of expandable graphite. The tensile strength of expandable graphite/polyurethane foam composites decreased with the content of the expandable graphite and the analysis of cell shape by SEM has shown that as the expandable graphite content increases, the cell becomes uneven and collapses. As the results of the compressive strength, density and air permeability tests, it was found that density and as the content of the expandable graphite increased, the compressive strength of the composites increased but air permeability decreased. When the amount of expandable graphite was added at 10 phr or higher, the foam has excellent flame retardation performance. Analysis of the degree of diffraction by X-ray diffraction (XRD) showed that as the content of the expandable graphite increased, the crystal peak of the graphite appeared near $2{\theta}=26^{\circ}$.

Gas Permeation Study of Fuel Hose Composed as Inner Material of FKM Rubber (FKM 고무를 내층재료로 한 연료호스의 가스 투과성 연구)

  • Kim, Do-Hyun;Doh, Kyung-Hwan;Park, Hyun-Ho;Lee, Chang-Seop
    • Elastomers and Composites
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    • v.40 no.2
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    • pp.83-92
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    • 2005
  • To develop an automotive fuel hose suitable to the international environmental regulation, FKM rubber materials as an inner material of fuel hole were prepared with different chemical compositions. Measurement of the properties of thermal resistance, oil resistance, fuel resistance, gas permeability including fundamental properties were performed to investigate compatibility for a fuel hose material. Fundamental properties, thermal resistance, oil resistance, fuel resistance and permeability of FKM rubber materials were improved with fluorine content. When the carbon content was 20 phr, FKM compounds with fluorine contents of 66%, 09% and 71% were shown to satisfy the specification oi fuel hose. The gas permeability of NBR and FKM compounds was measured on the mixed fuel oils prepared with isooctane-toluene and gasoline-methanol. FKM rubber materials showed a small difference in penetrated amount of fuel and showed a permeability superior to NBR material. he permeability of FKM rubber materials was not influenced by the contents of fuel oil. Thermal properties of 69% FKM rubber experienced by permeability testing were not variated.