• 공업화학
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• 제16권6호
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• pp.827-833
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• 2005

본 연구에서는 폴리아미드계 수지를 이용하여 최적의 핫멜트 접착제 배합설계를 접착제 합성, 물성평가 및 철에 대한 접착력 평가를 통해 구축하고자 하였다. 최적 배합설계를 위해 앞선 연구결과에 따라 CM831과 843P의 기본 수지에 점착부여수지로 테르펜수지의 무게비를 각각 75/25/10으로 고정한 후 왁스, 충전제 등이 사용되었으며 이들의 종류와 첨가량이 접착제의 흐름 특성과 접착력에 미치는 영향을 조사하였다. 결과에 따르면 왁스의 경우 폴리에틸렌 왁스의 첨가량이 증가함에 따라 용융점도는 다소 감소하였지만 철과의 최적 접착력은 5 wt%에서 나타났다. 이는 접착제 자체의 기계적 물성과 밀접한 관계가 있음을 알 수 있었다. 충전제의 경우는 탈크가 10 wt% 첨가되었을 때 다소 높은 용융점도에 비해 우수한 접착성능을 나타내었다.

• 공업화학
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• 제3권1호
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• pp.81-87
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• 1992

폴리에틸렌에 아라미드단섬유를 보강시킨 복합재료를 roll mill을 사용하여 제조하였다. 섬유배향과 물리적 성질의 이방성을 주사전자현미경과 인장시험기로, 유변특성을 RDS 를 사용하여 측정하였다. 섬유의 배향은 roll 작업으로 어느 정도 이루어 졌으며, 섬유 loading 이 증가할수록 기계적강도의 이방성도 증가하였다. 섬유 loading 에 따른 복합점도의 상승은 저주파수 영역에서 뚜렷이 관찰되었으며, 특히 섬유 loading 이 작은 범위에서 현저하였다.

• 한국주조공학회지
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• 제25권5호
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• pp.203-208
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• 2005

The main emphasis of this study is to optimize the process variables for manufacturing aluminum foam materials by direct foaming of remelted aluminum scraps. Aluminum foams were fabricated from two different raw materials, pure aluminum and used beverage cans. For both cases, $TiH_{2}$ was used as a foaming agent. Calcium was added as a thickener for the foaming of pure aluminum and no thickener was added for that of used beverage Cans because the pre-existing oxides of the used beverage cans are used as a thickener. Calcium and $TiH_{2}$ content varies from 0.5wt.% to 2.0wt.% and from 0.5wt.% to 1.5wt.%, respectively. The processing conditions, such as the effect of calcium on the melt viscosity, foaming temperature, and the optimum amount of the foaming agent with regard to the melt viscosity were discussed.

• Fibers and Polymers
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• 제3권3호
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• pp.103-108
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• 2002

The viscosity effect of matrix polymer on melt exfoliation behavior of an organoclay in poly($\varepsilon$-caprolactone) (PCL) was investigated. The viscosity of matrix polymer was controlled by changing the molecular weight of poly($\varepsilon$-eaprolactone), the processing temperature, and the rotor speed of a mini-molder. Applied shear stress facilitates the diffusion of polymer chains into the gallery of silicate layers by breaking silicate agglomerates down into smaller primary particles. When the viscosity of PCL is lower, silicate agglomerates are not perfectly broken into smaller primary particles. At higher viscosity, all of silicate agglomerates are broken down into primary particles, and finally into smaller nano-scale building blocks. It was also found that the degree of exfoliation of silicate layers is dependent upon not only the viscosity of matrix but thermodynamic variables.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.311-318
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• 2001

A three-dimensional numerical analysis of the flow and heat transfer characteristic of wood-flour-filled polypropylene melt in an extrusion die was carried out Used for this analysis were Finite Concept Method based on FVM, unstructured grid and non-Newtonian fluid viscosity model. Temperature and flow fields are closely coupled through temperature dependent viscosity and viscous dissipation. With large Peclet, Nahme, Brinkman numbers, viscous heating caused high temperature belt near die housing, Changing taper plate thickness and examining some predefined parameters at die exit investigated the effect of taper plate on velocity and temperature uniformities. In the presence of taper plate, uniformity at die exit could be improved and there existed an optimum thickness to maximize it.

• 한국염색가공학회지
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• 제22권2호
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• pp.155-162
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• 2010

Nylon 6 was blended with a brominated epoxy resin, tetrabromobisphenol A diglycidyl ether (DGEBBA), to enhance flame retardant property. Thermal properties of the blends were analyzed by DSC. Melting point and crystallization temperature decreased as the amount of epoxy resin increased. Melt index and relative viscosity decreased as the amount of the epoxy resin increased. When the blended amount of the epoxy resin was below 5%, the melt index decreased while the relative viscosity slightly increased. The blend resin was successfully spun into fiber without swelling or drawing the resonance phenomena. However, both the tenacity and elongation of the fiber decreased by increasing the amount of the DGEBBA.

• Elastomers and Composites
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• 제50권1호
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• pp.49-54
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• 2015

Dynamically vulcanized PMMA/ACM (80 wt%/20 wt%) blend using DCP as a curing agent was prepared using internal mixer. The morphology, mechanical properties, optical properties, melt viscosity and die swell were characterized by using FE-SEM, tensile test, Izod impact test, dynamic mechanical analysis, ARES and capillary rheometer, respectively. The blends show a phase-separated morphology in which ACM are dispersed in PMMA matrix. Dynamically vulcanized blend exhibits higher mechanical properties, higher melt viscosity, and die swell as compared to simple blend. And, the dynamically vulcanized blend showed total transmittance of more than 75% and haze of higher than 90%, which enable it to find potential applications to fabricate an optical diffuser by extrusion process.

• 한국식품조리과학회지
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• 제19권2호
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• pp.216-222
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• 2003

The effects of hydrolysis times and calcium source additions (calcium lactate, calcium carbonate), on the qualify characteristics of soy ice cream prepared with soy protein isolate(SPI), were studied. Increasing the hydrolysis time decreased the viscosity and overrun of soy ice creams, but increased the melt-down property. The addition of calcium lactate increased the viscosity of the soy ice cream mix, but no changes were observed from the calcium carbonate addition. The overrun of calcium lactate samples was higher than on addition of calcium carbonate. The addition of calcium lactate and calcium carbonate resulted in decreased melt-down properties, although these effects were more evident in the calcium lactate samples. However, calcium carbonate addition resulted in higher scores in the overall quality of the soy ice creams. In conclusion, better soy ice cream could be prepared by treating the SPI with Flavorzyme for 50 min, along with calcium fortification in the form of calcium carbonate.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.65-66
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• 2003

Ternary blend fibers (TBFs) based on melt blends of PEN, PET, and TLCP were prepared by melt blending and spinning to achieve high performance fibers. The reinforcement effect and the TLCP fibrillar structure resulted in the improvement of mechanical properties for TBFs. Molecular orientation was an important factor in determining the tensile strength and modulus of TBFs. Another part of this research is silica nano-particle filled PEN composites were melt-blended to improve mechanical and physicalproperties, and processability. The tensile modulus and strength were improved adding silica nano-particles to the PEN. The decreased melt viscosity by the fumed silica resulted in the improvement of the processability. The fumed silica may act as a nucleating agent in the PEN matrix.

• 한국자기학회지
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• 제8권3호
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• pp.150-155
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• 1998

플라스틱 이방성 페라이트 자석에서 페라이트 분말함량 변화에 레올로지와 자기특성의 변화를 조사하였다. 분말함량 변화에 따른 상대점도의 측정값과 이론식을 비교하였다. 분말함량 증가에 따른 혼합물의 상대점도 증가경향과 플라스틱자석의 분말배향도의 감소경향은 정확히 일치하였다. 일정한 자장하에서 사출성형된 플라스틱 이방성 페라이트 자석에서 잔류자속밀도와 최대자기에너지적은 분말함량 증가에 따라 적선적으로 증가하다가 다시 감소하여 극대값을 나타냈으며, 극대값 이후의 자기특성 가소는 분말배향도의 급격한 감소에 기안하였다. 자기특성 극대값을 나타내는 분말한량은 사출형성시 자장의 세기와 결합체의 용융점도에 의존하며, 높은 자기특성을 위해서는 낮은 용융점도의 결합제 사용이 필요하다.