• Title/Summary/Keyword: Polymer Material

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[ $SiO_2$ ] Effect on the Electrochemical Properties of Polymeric Gel Electrolytes Reinforced with Glass Fiber Cloth ($SiO_2$가 유리섬유로 보강된 고분자 겔 전해질의 전기 화학적 특성에 미치는 영향)

  • Park Ho Cheol;Kim Sang Heon;Chun Jong Han;Kim Dong Won;Ko Jang Myoun
    • Journal of the Korean Electrochemical Society
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    • v.4 no.1
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    • pp.6-9
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    • 2001
  • [ $SiO_2$ ] effect on the electrochemical properties of polymeric gel electrolytes(PGEs) reinforced with glass fiber cloth(GFC) was investigated . PGEs were composed of polyacrylronitrile(PAN), poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)), $LiClO_4$ and three kind of plasticizer(ethylene carbonate, dietyl carbonate, propylene carbonate). $SiO_2$ was added to PGEs in the weight fraction of 10, 20, $30\%$ respectively. PGEs containing $SiO_2$ showed conductivity of over $10^{-3}S/cm\;at\;23^{\circ}C$ and electrochemical stability window to 4.8V. In the impedance spectra of the cells, which were constructed by lithium metals as electrodes, interfacial resistance increased due to growth of passivation layer during storage time and remarkable difference was not observed with content of $SiO_2$. In the impedance spectra of the lithium ion polymer batteries consisted of $LiClO_2$ and mesophase pitch-based carbon fiber(MCF), ohmic cell resistance of $SiO_2-free$ PGE was changed continuously with number of cycle, but those of $SiO_2-dispersed$ PGEs were not. Discharge capacity of the PGE containing $20wt\%\;SiO_2$ showed 132 mAh/g at 0.2C rate and $85\%$ of discharge capacity was retained at 2C rate.

Efficient Delivery of Toxoid Antigens using Micro/Nano-carriers (마이크로/나노-운반체를 이용한 톡소이드 항원의 효과적인 전달 방법)

  • Park, Ga-Young;Ahn, Gna;Lee, Se Hee;Kim, Sang Bum;Kim, Yang-Hoon;Ahn, Ji-Young
    • Journal of Life Science
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    • v.28 no.4
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    • pp.496-507
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    • 2018
  • Immunization has been performed for centuries and is generally accepted as a sustainable method of controlling bacteria, viruses, and mediated and infectious diseases. Despite many studies having been performed on animal subjects to demonstrate the importance of toxin immunity, the use of toxoid vaccines in humans and animals has been limited for a long time. Recently, the development of the toxoid antigen delivery system has been facilitated using novel nano-medicinal technology. The micro/nano-carrier has been used to improve vaccination coverage as well as reduce vaccine costs. A micro/nano-carrier is a micro/nano-sized material that delivers immune cargo, including recombinant or peptide toxoid antigens. These toxoid antigens are either encapsulated in the interior or displayed on the surface of micro/nano-carriers as a way to protect them from the cellular machinery. In particular, the combination of toxoid antigens and micro/nano-carriers can induce phagocytosis through the specific interactions between GCs and macrophages; thus, the toxoid antigens can be delivered easily into the macrophages. This paper reviews recent achievements of micro/nano-carriers in the field of vaccine delivery systems such as microbial ghost cells (GCs, Bacterial ghost cells and Yeast ghost cells), gene-manipulated outer membrane vesicles (OMVs) and biocompatible, polymer-based nanoparticles (NPs, NP-Carrier and NP-Cage). Finally, this review shows various aspects in terms of the hosts' immune responses.

Separation and Purification of 2,6-dimethylnaphthalene in the Light Cycle Oil(I) -Concentration of a mixture of dimethylnaphthalene isomers in the light cycle oil- (접촉분해경유에 함유된 2,6-dimethylnaphthalene의 분리, 정제(I) -접촉분해경유에 함유된 dimethylnaphthalene이성체 혼합물의 농축-)

  • Kim, Su-Jin;Kim, Sang-Chai;Kawasaki, Junjiro
    • Applied Chemistry for Engineering
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    • v.7 no.1
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    • pp.162-170
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    • 1996
  • Light cycle Oil(LCO) contains 2,6-dimethylnaphthalene (2,6-DMNA) which is used as the basic material for high performance engineering plastics and liquid crystal polymer. This study was experimentally investigated to concentrate a mixture of dimethylnaphthalene(DMNA) isomers in the LCO by extraction-distillation combination as a pretreatment for separation and purification of 2,6-DMNA in the LCO. Furthermore, concentration of a mixture of DMNA isomers in the LCO compared between distillation and extraction-distillation combination. The recovery of aromatics in the LCO was performed by batch cocurrent multistage extraction with dimethylsulfoxide and water mixture as solvent. The concentration of naphthalene group(carbon number 10-12) in the extracted mixture is higher than that in the LCO. The yield for naphthalene group increased with decreasing carbon number. The yield for a mixture of DMNA isomers obtained in 5 equilibrium extration runs was about 65%. the separation of individual components with extractedmixture was tested by batch distillation. Futhermore, for recovery of a mixture of DMNA isomers of high concentration, distillate containing DMNA was distilled. As a result, a mixture of DMNA isomers with high concentration such as 60wt% was recovered. The extraction-distillation combination was more effective than the distillation to concentration a mixture of DMNA isomer in the LCO.

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Thermal Properties of Two-Layered Materials Composed of Dielectric Layer on Metallic Substrate along the Thickness Direction (금속기판에 유전체 후막을 형성시켜 제조한 2층 층상재료에서 두께 방향의 열전도 특성)

  • Kim, Jong-Gu;Jeong, Ju-Young;Ju, Jae-Hoon;Park, Sang-Hee;Cho, Young-Rae
    • Journal of the Microelectronics and Packaging Society
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    • v.23 no.4
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    • pp.87-92
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    • 2016
  • The importance of heat dissipation for the electric device modules along the thickness direction is increasing. Two types of two-layered materials, metal-metal bonding and dielectric-metal bonding, have been fabricated by roll bonding process and a thermal diffusivity of the specimens was measured along the thickness direction. The thermal diffusivity of specimens with metal-metal bonding measured by light flash analysis (LFA) showed a same value independent on the direction of heat flow. However, the thermal diffusivity of specimens with dielectric-metal bonding showed a big difference of 17.5% when the direction of heat flow changed oppositely in the LFA process. The measured thermal diffusivity of specimens when the heat flows from metal to dielectric direction showed smaller value of 17.5% compared to the value when the heat flow from dielectric to metal direction. The difference in thermal diffusivity of specimens with dielectric-metal bonding dependence on direction of heat flow is due to the electron-phonon resistance that occurred transfer process of electron energy to phonon energy near the interface.

Improving Charge Injection Characteristics and Electrical Performances of Polymer Field-Effect Transistors by Selective Surface Energy Control of Electrode-Contacted Substrate (에폭시 개질 한 다관능 아크릴레이트를 포함하는 충격 저항성이 향상된 불포화폴리에스터 SMC (Sheet Molding Compound) 소재제조 및 그의 물성연구)

  • Jang, Jeong Beom;Kim, Taehee;Kim, Hye Jin;Lee, Wonjoo;Seo, Bongkuk;Kim, Yongsung;Kim, Changyoon;Lim, Choong-Sun
    • Journal of Adhesion and Interface
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    • v.21 no.3
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    • pp.101-106
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    • 2020
  • In this study, epoxy-modified acrylate was synthesized. The synthesized acrylate was added to the composition for sheet molding compound (SMC) in the range of 5 phr to 15 phr. The prepared SMC prepreg was molded at high temperature and pressure to produce a glass fiber reinforced composite. Physical properties such as tensile and impact strength of the composite were measured, respectively. Experimental data show that the composite with 5 phr of synthesized acrylate has 20% improved tensile strength and 12% improved impact strength than that of the reference sample.

Processability of Bio-composites Applied Polyolefin to Recycled Fiberboard Flour (Polyolefin계 고분자에 섬유판 가공 부산물을 적용한 환경 친화형 바이오복합재의 가공성)

  • Choi, Seung-Woo;Kim, Hee-Soo;Lee, Byoung-Ho;Kim, Hyun-Joong;Ahn, Sye-Hee
    • Journal of the Korean Wood Science and Technology
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    • v.33 no.6 s.134
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    • pp.55-62
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    • 2005
  • This study was conducted to evaluate the application of a bio-composite made by the addition recycled fiber board flour as filler. Recycled fiber board (high density fiber board, HDF) flour was added to polyolefin polymer low density polyethylene (LDPE) and polypropylene (PP) for the preparation of bio-composite materials. The mechanical properties and processability of the recycled HDF flour filled LDPE and recycled HDF flour filled PP bio-composites were then measured and compared to those of wood flour (WF) and rice-husk flour (RHF) filled LDPE and PP bio-composites, respectively. The tensile and impact strengths of the recycled HDF flour filled LDPE and PP bio-composites had similar mechanical properties to those of the WF and RHF filled LDPE and PP bio-composites. To measure the processability, torques of the bio-composites were also measured. The torques of the HDF flour filled LDPE and PP bio-composites were lower than those of the WF and RHF filled polyolefin (PP and LDPE) bio-composites with a filler loading of 30 wt.%. This result showed definite processability, which was not related with the distribution of the particle size of the material added. The recycled fiber board flour filled bio-composites showed applicability as substitutes for the bio-composites currently used in the bio-composites industry.

UV-nanoimprint Patterning Without Residual Layers Using UV-blocking Metal Layer (UV 차단 금속막을 이용한 잔류층이 없는 UV 나노 임프린트 패턴 형성)

  • Moon Kanghun;Shin Subum;Park In-Sung;Lee Heon;Cha Han Sun;Ahn Jinho
    • Journal of the Microelectronics and Packaging Society
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    • v.12 no.4 s.37
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    • pp.275-280
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    • 2005
  • We propose a new approach to greatly simplify the fabrication of conventional nanoimprint lithography (NIL) by combined nanoimprint and photolithography (CNP). We introduce a hybrid mask mold (HMM) made from UV transparent material with a UV-blocking Cr metal layer placed on top of the mold protrusions. We used a negative tone photo resist (PR) with higher selectivity to substrate the CNP process instead of the UV curable monomer and thermal plastic polymer that has been commonly used in NIL. Self-assembled monolayer (SAM) on HMM plays a reliable role for pattern transfer when the HMM is separated from the transfer layer. Hydrophilic $SiO_2$ thin film was deposited on all parts of the HMM, which improved the formation of SAM. This $SiO_2$ film made a sub-10nm formation without any pattern damage. In the CNP technique with HMM, the 'residual layer' of the PR was chemically removed by the conventional developing process. Thus, it was possible to simplify the process by eliminating the dry etching process, which was essential in the conventional NIL method.

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Long-term clinical and experimental/surface analytical studies of carbon/carbon maxillofacial implants

  • Szabo, Gyorgy;Barabas, Jozsef;Bogdan, Sandor;Nemeth, Zsolt;Sebok, Bela;Kiss, Gabor
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.37
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    • pp.34.1-34.14
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    • 2015
  • Background: Over the past 30-40 years, various carbon implant materials have become more interesting, because they are well accepted by the biological environment. The traditional carbon-based polymers give rise to many complications. The polymer complication may be eliminated through carbon fibres bound by pyrocarbon (carbon/carbon). The aim of this study is to present the long-term clinical results of carbon/carbon implants, and the results of the scanning electron microscope and energy dispersive spectrometer investigation of an implant retrieved from the human body after 8 years. Methods: Mandibular reconstruction (8-10 years ago) was performed with pure (99.99 %) carbon implants in 16 patients (10 malignant tumours, 4 large cystic lesions and 2 augmentative processes). The long-term effect of the human body on the carbon/carbon implant was investigated by comparing the structure, the surface morphology and the composition of an implant retrieved after 8 years to a sterilized, but not implanted one. Results: Of the 16 patients, the implants had to be removed earlier in 5 patients because of the defect that arose on the oral mucosa above the carbon plates. During the long-term follow-up, plate fracture, loosening of the screws, infection or inflammations around the carbon/carbon implants were not observed. The thickness of the carbon fibres constituting the implants did not change during the 8-year period, the surface of the implant retrieved was covered with a thin surface layer not present on the unimplanted implant. The composition of this layer is identical to the composition of the underlying carbon fibres. Residual soft tissue penetrating the bulk material between the carbon fibre bunches was found on the retrieved implant indicating the importance of the surface morphology in tissue growth and adhering implants. Conclusions: The surface morphology and the structure were not changed after 8 years. The two main components of the implant retrieved from the human body are still carbon and oxygen, but the amount of oxygen is 3-4 times higher than on the surface of the reference implant, which can be attributed to the oxidative effect of the human body, consequently in the integration and biocompatibility of the implant. The clinical conclusion is that if the soft part cover is appropriate, the carbon implants are cosmetically and functionally more suitable than titanium plates.

Cytotoxicity of Hyaluronic Acid Membrane Cross-linked with Lactide (락타이드로 가교시킨 히아루론산 막의 세포독성)

  • Kim, Won-Jung;Kwon, Ji-Young;Cheong, Seong-Ihl;Kim, In-Seop
    • KSBB Journal
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    • v.21 no.4
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    • pp.255-259
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    • 2006
  • The biodegradable hyaluronic acid(HA) membranes cross-linked with lactide using the crosslinking agent, 1-ethyl-3(3-dimethyl aminopropyl) carbodiimide(EDC) were prepared as a potential biocompatible material for tissue engineering. HA membranes having different mechanical properties were synthesised by varying degree of the mole ratio of lactide to HA, EDC concentration, and crosslinking temperature. HA membranes were degradable in water solution and the degradation became slower with the increasing mole ratio of lactide to HA. HA membranes were sterilized using ethylene oxide gas and extracted with cell culture medium for 24 h at $37^{\circ}C$ and 200 rpm. Cytotoxicity of the extract was tested using NIH/3T3 mouse embryo fibroblast as a model cell. Growth inhibition was not observed in the extracts of HA membranes with the mole ratios of lactide to HA, 5 or 10, and 10% EDC concentration, however 11% of growth inhibition was observed in the extract with the mole ratio of 13. Growth inhibition was not observed in the extracts of HA membranes prepared with 5% EDC or 10% EDC and the mole ratio of lactide to HA, 10, however 12% of growth inhibition was observed in the extract with 20% EDC. Cytotoxicity was not observed in the extracts of HA membranes prepared at varying crosslinking temperatures, $15^{\circ}C,\;25^{\circ}C,\;and\;28^{\circ}C$ with the mole ratio of lactide to HA, 10 and 10% EDC.

Solution processed doping to the polymer hole transporting layer for phosphorescent organic light-emitting diodes (고분자 정공수송층에 용액 공정 도핑법을 적용한 인광 유기전기발광소자)

  • Sung, Baeksang;Lee, Jangwon;Lee, Seung-Hoon;Yoo, Jae-Min;Lee, Jae-Hyun;Lee, Jonghee
    • Journal of IKEEE
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    • v.24 no.3
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    • pp.699-705
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    • 2020
  • In this study, a facial way to enhance the electrical properties of organic light-emitting diodes (OLEDs) via the solution process doping method based on the poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl) diphenylamine)] (TFB) as a hole transporting layer (HTL) is demonstrated. In the TFB solution of the hole transport material, 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) was doped by 3 wt% to improve the electrical properties of the HTL. According, the OLED with HAT-CN doped TFB showed the increased current density and luminance at the same driving voltage on behalf of the improved conductivity of HTL, and the reduced turn-on voltage from 13 V to 9 V. Furthermore, the maximum external quantum efficiency was dramatically increased three times from 3.6 to 10.8 % compared to the reference device without appling doping methode.