• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.632-635
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• 2007

Automobile tire has very complicated shape and is composed of rubber, steel cord and ply cord, Tread pattern of tire is very essential for the basic characteristics of tire, such as braking, acceleration and comfortableness. Tire components such as tread, sidewall, and spex are prepared by forcing uncured rubber compound through an extruder to shape during curing process. Because of its complexity of shape, adaptive mesh refinement was used for the analysis of tire tread. Effects of forming variables were evaluated.

• 한국분말재료학회지
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• 제18권2호
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• pp.181-187
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• 2011

PVDF was used as a polymeric matrix material in this work. Nickel powders with average particles size of 200 nm or 72 nm were used as fillers. PVDF/metal submicro- and nanocomposites were prepared by means of a mixing in twin screw extruder and planetary ball mill, respectively. All samples were prepared by hot pressing method. Their electrical, thermal and morphological properties were examined by dielectric spectroscopy, DSC, FTIR, XRD, optical microscopy and scanning electron microscopy. It was found that all properties of composites were strongly modified depending on the content of metal powders and filler particles size. Particularly, specific volume resistivity of PVDF/Ni composite with 0.2 wt.% of Ni was increased by factor of 1.5~4.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.291-291
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• 2006

Two different sources of clay, Na-Bentonite (Thai local clay) and Na-Montmorillonite were modified with Hexadodeccyltrimethyl ammonium bromide. The nanocomposites of polypropylene were successfully prepared via melt blending in a co-rotating twin screw extruder by using PP-g-MA as a compatibilizer at various contents of organoclays. The morphology of nanocomposites was investigated by using XRD and SEM. The results showed that the intercalated and exfoliated structures were obtained. The thermal behavior was also studied by using DSC and TGA. The degradation temperature of filled PP was greater than that of unfilled PP by 20%. And, the tensile strength and modulus were improved when a small amount of organoclays were added.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.280-280
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• 2006

Na-bentonite (local clay mineral) and Na-montmorillonite were treated with quaternary alkylammonium cations. The effect of the molecular structure and functional groups of the surfactants on the organoclays was investigated by X-ray diffraction (XRD). For the preparation of nanocomposites, organoclays were melt-blended with polypropylene in a twin screw extruder and $Surlyn^{(R)$. ionomer was used as a reactive compatibilizer. The clay dispersions in the composites were investigated by X-ray diffraction (XRD). XRD spectra showed no peak at low angle indicated that the silicate clay layer has a nearly exfoliated dispersion in the polymer matrix. Thermal and mechanical properties of nanocomposites were higher than those of PP.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.367-367
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• 2006

With poly (ethylene-co-methacrylic acid) ionomer (i.e. Surlyn) as a compatibilizer, PP/organoclay (Cloisite(R)20A) nanocomposites were prepared via melt compounding in a co-rotating twin-screw extruder. For comparison, the widely used PP-g-MA was also used as a reference. The content of organoclay was fixed at 5phr based on the total weight of polymer resins. The structures of nanocomposites were characterized by XRD, rheometry in small amplitude oscillatory shear, SEM, and TEM, respectively. It was found that PP/Surlyn/OMMT nanocomposites displayed higher intercalation degree and better dispersion effect than the corresponding PP/PP-g-MA/OMMT counterpart. Additionally, their mechanical properties and wettability were measured.

• 유변학
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• 제8권3_4호
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• pp.187-198
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• 1996

최근에 본 연구자에 의해서 단축 스크류 공정에서 카오스 스크류라고 명명되어진 카오스 혼합장치가 성공적으로 개발되었다. 기하학적 조건이나 공정조건에 대한 설계변수로 카오스 스크류를 설계하기 위하여 체류시간, 포인카레 단면 그리고 혼합패턴등에 대한 계산 과 해석이 이루어져야 하는데 이를 단지 Runge-Kutta 방법에 의해 속도장을 적분한다면 상당한 계산시간이 소비된다. 이러한 수치문제를 극복하기 위하여 본논문에서는 새로운 사 상법을 제안한다. 이 방법으　 사용하면 벽면 근처의 특이점 영역에서도 수치문제가 해결된 다. 본 논문에서 제안하는 수치사상법은 Runge-Kutta 방법에 비하여 수치계산의 효율성과 정확도 면에서, 특히 유안요소법으로 얻은 속도장에 대하여 우수함이 밝혀졌다. 이러한 사상 법은 공간주기 유동장뿐만 아니라 시간주기 유동장에서 적용할수 있다.

• Fibers and Polymers
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• 제7권1호
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• pp.36-41
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• 2006

PVC and SAN are often mixed to compensate for the disadvantages of each polymer. Miscibility and thermal stability of PVC/SAN blend were investigated in this study by blending SAN polymer having 20, 24, 28, 32 % of acrylonitrile contents. Two polymers were mixed using a melt blending method with a single screw extruder. DSC thermogram was used to evaluate miscibility of the two polymers. SAN having 24 % of acrylonitrile showed the best miscibility with PVC. In order to evaluate degradation behavior, blended polymer was heat treated in DSC furnace and glass transition temperature was measured consecutively. Glass transition temperature increased continuously with annealing time due to degradation and cross-linking of polymer chains. Melt index of blended polymer was always higher than that of PVC.

• Carbon letters
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• 제11권2호
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• pp.83-89
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• 2010

We prepared polycarbonate (PC)/poly(methyl methacrylate) (PMMA)/multiwall carbon nanotube (MWCNT) nanocomposites by co-rotating twin screw extruder at 533 K. Thermal analysis results indicate that the miscibility of PC and PMMA is enhanced by MWCNTs. Bead necklace-like morphology of PMMA-rich phase is observed in PC/PMMA/MWCNT nanocomposites with increasing PMMA weight fraction due to the bead necklace-like morphology. The tensile strength of PC/PMMA (75/25)/MWCNT (1 wt.%) nanocomposite is 3% higher than those of PC/PMMA (75/25) alloy. Suppression of die swell by MWCNT filler is observed in the melt flow of PC/PMMA/MWCNT nanocomposites during extrusion.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.99-102
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• 2005

Plasma surface coating is applied to the wood powder to improve its bonding and dispersion with the polypropylene(PP). Some mechanical test results and visual inspection indicates the good compatibility between the wood powder and the PP, and relatively good interfacial adhesion between wood powder and PP matrix was seen. Also, this method is considered as a non-toxic process as compared to other direct chemical method.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.28-33
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• 2001

Screw conveyors are used extensively in industrial for conveying and elevating materials. Despite their apparent simplicity, the mechanics of the conveying action is very complex. so many engineers depend on experiential data. Capacities of screw are pumping, steady flow of polymer melts, steady volumetric throughput etc. they are affected by geometry of screw, heat flux, pressure on inside barrel, rotating velocity, friction coefficient at screw surface etc. by computation volumetric efficiency increases as rotating velocity increases and decreases as friction coefficient increases. also it decreases with short pitch length. and double flight screw is more effective than single flight screw. The temperature of polymer melts by heating pad and injection pressure play a very important role in the injection molding machine. so in this paper we analyze thermal distortion and stress of screw includes pressure and temperature distributions by finite element analysis to understand what design factors influence on volumetric throughput efficiency of the screw and thermo-mechanical characteristics of screw.