• Proceedings of the Korean Fiber Society Conference
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• 1993.06b
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• pp.661-666
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• 1993

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.646-649
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• 1995

An experimental and analyical investigations were undertaken to improve understanding of spring-back phenomena of chopped fiber reinforced thermoplastic composite sheet. The materials tested contained 20, 35, 40 percent by weight of readomly oriented glass fiber in a prolypropylene matrix. The simple bending tests were performed at temperatures ranging form 75 .deg. c to 150 .deg. c with 25 .deg. c increment and at punch speed of 1mm/sec and 0.01mm/sec. The spring-back angel measured in pure bending is compared with the prediction base on the analytical model. Good agreement between experimental and predicted results was observed.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.9-12
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• 2001

Blending is an easy and popular means to achieve a desired set of characteristic properties. The blends, by melt mixing of thermoplastic materials and elastomer, have received considerable attention in recent years. It is well known that nearly all blends comprise one polymer domain dispersed in the matrices of the other polymer [1]. (omitted)

• Composites Research
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• v.28 no.4
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• pp.168-175
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• 2015

Recently, the applications of carbon fiber reinforced plastics (CFRPs) have become broader than ever when it comes to such industries as automotive, ships, aerospace and military because of their lightweight-ness and high mechanical properties. Thermosetting plastics like epoxy are frequently used as the binding matrix in CFRPs due to their high hardness, wetting characteristics and low viscosity. However, they cannot melted and remolded. For this reason, thermosetting plastic wastes have caused serious environmental problems with the production of fiber reinforced plastics. Thus, many studies have focused on the carbon fiber reinforced thermoplastics (CFRTPs) and recycling carbon fiber. In this study, recycled carbon fiber (RCF) was prepared from CFRPs using a pyrolysis method, which was employed to separate resin and carbon fiber. The degree of decomposition for epoxy resin was confirmed from thermal gravimetric analysis (TGA) and scanning electron microscope (SEM). The RCF was cut and ground to prepare a carbon fiber composite sheet (CFCS). CFCS was manufactured by applying recycled carbon fibers and various thermoplastic fibers. Various characterizations were performed, including morphological analyses of surface and cross-section, mechanical properties, and crystallization enthalpy of CFCS at different cooling conditions.

• Macromolecular Research
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• v.17 no.5
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• pp.285-288
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• 2009

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.2
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• pp.158-163
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• 2003

Thermosetting matrix composites have disadvantages in terms of moulding time, repairability and manufacturing cost. Thus the high-performance thermoplastic composites to eliminate such disadvantages have been developed so far. As a result of environmental and economical concerns, there is a growing interest in the use of thermoplastic composites. However, since their mechanical properties are very sensitive to the environment such as moisture, temperature etc., those behaviors need to be studied. Particularly the temperature is a very important factor influencing the mechanical behavior of thermoplastic composites. The effect of temperature have not yet been fully quantified. Since engineering applications of reinforced composites necessitate their fracture mechanic characterization, work is in progress to investigate the fracture and related failure behavior. An approach which predicts the tensile strength was perpormed in the tensile test. The main goal of this work is to study the effect of temperature on the result of tensile test with respect to GF/PE composite. The tensile strength and failure mechanisms of GF/PE composites were investigated in the temperature range 6$0^{\circ}C$ to -5$0^{\circ}C$. The tensile strength increased as the fiber volume fraction ratio increased. The tensile strength showed the maximum at -5$0^{\circ}C$, and it tended to decrease as the temperature increased from -5$0^{\circ}C$. The major failure mechanism was classified into the fiber matrix debonding, the fiber pull-out, the delamination and the matrix deformation.

• Composites Research
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• v.37 no.3
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• pp.197-203
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• 2024

Mechanical, electrical and thermal properties of polymer composites can be improved simultaneously by incorporating carbon fibers (CFs), which are beneficial for improving the mechanical properties, and multi-walled carbon nanotubes (MWCNTs), which are advantageous for improving the conductive properties. In this study, MWCNTs were incorporated into carbon long fiber thermoplastic (CLFT), which has excellent mass production processability and excellent mechanical properties, to control electrical and thermal properties. The mechanical and electrical properties of the prepared composites were most significantly influenced by the amount of filler incorporated. On the other hand, the thermal properties were improved due to the formation of a filler network interconnected by the incorporation of MWCNTs. By adjusting the filler amount, filler composition, and filler network structure of MWCNT-incorporated CLFT, the mechanical, electrical, and thermal properties could be controlled.

• Design & Manufacturing
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• v.15 no.3
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• pp.39-44
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• 2021

In molding of continuous fiber-reinforced thermoplastic composites, it is very difficult to impregnate between the reinforcements and the matrix since the matrix has a high melting temperature and high viscosity. Therefore, most of composite molding processes are divided in the manufacturing processes of intermediate materials called prepreg and the forming of products from intermediate materials. The divided process requires additional facilities and thermoforming, and they increase the cycle time and cost of composite products. These problems can be resolved by combining the continuous fiber-reinforced composite molding process with injection molding. However, when a composite material is manufactured by inserting woven fabric into the injection mold, poor impregnation occurs on the surface of the molded product. It affects the properties of the composites. In this paper, through an impregnation experiment using cores with different heat transfer rates and pore densities, the reason for the poor impregnation was confirmed, and molding experiments were conducted to produce composite with improved surface impregnation by inserting the mesh. And also, the surface impregnation and deformation of composites molded using different types of mesh were compared with each other.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.243-246
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• 2002

자동차 차체 제작을 위해서는 차체의 견고성과 승객의 안전성을 동시에 고려하여 너무 강하거나 너무 무르지 않은 재질의 선택과 차체 설계의 최적화가 요구된다. 본 논문에서는 차량 충돌 시 자동차의 안전도를 향상시키면서 차량의 손상을 최소화 함으로써 수리비를 절감하기 위한 목적으로 TPU(Thermoplastic Polyurethane Elastomer)에 공기를 채워서 만든 에어백 자동차 범퍼를 개발하였다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 1993.06a
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• pp.45-46
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• 1993