• Title/Summary/Keyword: Engineering polymer

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Stability-Enhanced Liquid Crystal Mode for Flexible Display Applications

  • Jung, Jong-Wook;Jang, Se-Jin;Lee, You-Jin;Kim, Hak-Rin;Jin, Min-Young;Kim, Jae-Hoon
    • Journal of Information Display
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    • v.6 no.2
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    • pp.1-6
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    • 2005
  • We demonstrated stability-enhanced liquid crystal (LC) displays using pixel-isolated LC mode in which LC molecules are isolated in pixel by horizontal polymer layer and vertical polymer wall. The device shows good electro-optic properties against external point or bending pressure due to the polymer structures. The polymer wall acts as supporting structure from mechanical pressure and prevents the cell gap from bending. Moreover, the polymer layer acts as an adhesive to ensure a tight attachment of the two substrates. We present herein various methods for producing polymer structures by using an anisotropic phase separation from LC and polymer composites or patterned micro-structures for stable flexible liquid crystal displays.

Stability-Enhanced Liquid Crystal Mode for Flexible Display Applications

  • Jung, Jong-Wook;Jang, Se-Jin;Lee, You-Jin;Kim, Hak-Rin;Jin, Min-Young;Kim, Jae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.687-691
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    • 2005
  • We demonstrated stability-enhanced liquid crystal (LC) displays using pixel-iosolated LC mode in which LC molecules are isolated in pixel by horizontal polymer layer and vertical polymer wall. The device shows good electro-optic properties with external pressure and bending due to the polymer structures. The polymer wall acts as supporting structure from mechanical pressure and maintains the cell gap from bending. Moreover, the polymer layer acts as adhesive for tight attachment of two substrates. We presented various methods to produce the polymer structures by using anisotropic phase separation from LC and polymer composites or patterned micro-structures.

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Study on Phase Separation of Carbon Dioxide-reducible Polymer Blends (이산화탄소 저감형 고분자 블렌드의 상 분리 특성연구)

  • Cho, Yong-Kwang;Kim, Yeong-Woo;Lee, Hak Yong;Park, Sang-Bo;Park, Chan-Young;Lee, Won-Ki
    • Journal of Environmental Science International
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    • v.24 no.1
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    • pp.9-15
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    • 2015
  • Sustainable and eco-friendly polymers, natural polymers, bio-based polymers, and degradable polyesters, are of growing interest because of environmental concerns associated with waste plastics and emissions of carbon dioxide from preparation of petroleum-based polymers. Degradable polymers, poly(butylene adipate-co-terephthalate) (PBAT), poly(propylene carbonate) (PPC), and poly(L-lactic acid) (PLLA), are related to reduction of carbon dioxide in processing. To improve a weak mechanical property of a degradable polymer, a blending method is widely used. This study was forced on the component separation of degradable polymer blends for effective recycling. The melt-mixed blend films in a specific solvent were separated by two layers. Each layer was analysed by FT-IR, DSC, and contact angle measurements. The results showed that each component in the PPC/PLLA and PPC/PBAT blends was successfully separated by a solvent.

Synthesis and Characterization of a New PPV Derivative Containing a Sterically Hindered 2,5-Dimethylphenyl Group

  • Kim, Yun-Hi;Lee, Hyun-Ouk;Lee, Ki-Suk;Kwon, Soon-Ki
    • Macromolecular Research
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    • v.11 no.6
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    • pp.471-475
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    • 2003
  • A new poly[2-(2',5'-dimethylphenyl)-1,4-phenylenevinylene] (PDMPPV) that features a bulky 2',5'-dimethylphenyl substituent, which can induce steric hindrance between the PPV backbone and the methyl groups, was designed and synthesized. The polymer structure having no TBB defects was confirmed by $^1$H-NMR and $\^$13/CNMR spectroscopy. The polymer showed good thermal stability with high T$\_$g/. The polymer film showed a maximum absorption at 415 nm with an absorption onset at 480 nm. The maximum emission peak showed at ca. 515 nm, with a shoulder at 530 nm. The turn-on voltages of ITO/PEDOT/PDMPPV/Al and ITO/PDMPPV/Al devices were 8 and 10 V, respectively. The electroluminescence spectrum from the device showed a maximum peak at 510 nm with a shoulder at ca. 535 nm.

Substitutional boron doping of carbon materials

  • Ha, Sumin;Choi, Go Bong;Hong, Seungki;Kim, Doo Won;Kim, Yoong Ahm
    • Carbon letters
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    • v.27
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    • pp.1-11
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    • 2018
  • A simple, but effective means of tailoring the physical and chemical properties of carbon materials should be secured. In this sense, chemical doping by incorporating boron or nitrogen into carbon materials has been examined as a powerful tool which provides distinctive advantages over exohedral doping. In this paper, we review recent results pertaining methods by which to introduce boron atoms into the $sp^2$ carbon lattice by means of high-temperature thermal diffusion, the properties induced by boron doping, and promising applications of this type of doping. We envisage that intrinsic boron doping will accelerate both scientific and industrial developments in the area of carbon science and technology in the future.

Optimization of Cure System for the ESBR Silica WMB and BR Silica DMB Blend Compounds

  • Yu, Eunho;Kim, Woong;Ryu, Gyeongchan;Ahn, Byungkyu;Mun, Hyunsung;Hwang, Kiwon;Kim, Donghyuk;Kim, Wonho
    • Elastomers and Composites
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    • v.54 no.2
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    • pp.97-104
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    • 2019
  • Emulsion styrene-butadiene rubber silica wet masterbatch (ESBR silica WMB) technology was studied to develop highly filled and highly dispersed silica compounds, involving the preparation of a composite by co-coagulating the modified silica and the rubber latex in a liquid phase. Previous studies have shown that when manufacturing ESBR silica WMB/Butadiene silica dry masterbatch (BR silica DMB) blend compounds, preparing BR silica dry masterbatch and mixing it with ESBR silica WMB gave excellent results. However, WMB still has the problem of lower crosslink density due to residual surfactants. Therefore, in this study, tetrabenzylthiuram disulfide (TBzTD) was added instead of diphenyl guanidine (DPG) in the ESBR silica WMB/BR silica DMB blend compounds and sulfur/CBS contents were increased to evaluate their cure characteristics, crosslink densities, mechanical properties, and dynamic viscoelastic properties. TBzTD was found to be more effective in increasing the crosslink density and to produce superior properties compared to DPG. In addition, with increasing sulfur/CBS contents, mechanical properties and rolling resistance were enhanced due to high crosslink density, but the abrasion resistance was not significantly changed because of the toughness.