• Proceedings of the Korean Fiber Society Conference
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• 1991.06b
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• pp.96-96
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• 1991

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.179-184
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• 2016

In this work, the influence of milled carbon fiber direction on mechanical properties of milled carbon fibers/carbon blacks/natural rubber compounds was investigated. The compounds were prepared by adding the 6 phr milled carbon fibers (MCFs) and 40 phr carbon blacks (CBs) into the natural rubber. The MCFs were aligned in a parallel and orthogonal direction in the compounds using two-roll-mill machine. Mechanical properties of compounds were studied by tensile characteristics and tearing strength. As a result, the compounds showed higher tensile strength, 100%~300% modulus, and tearing strength than those of using any other compounds due to the aligning MCFs in parallel. Mechanical properties of the compounds reinforced with non-aligned MCFs were inferior to those of others. Consequently, the parallel aligned MCFs in the compounds led to an increase of tensile properties and improvement of tearing strength, resulted from MCFs with the high elastic modulus.

• Elastomers and Composites
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• v.34 no.2
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• pp.113-120
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• 1999

Nobody doubts to say that one of the most important performance polymers is a conductive polymer. The manufacturing process of the commercial conductive polymers has been known by mixing with the conductive materials, but it doesn't noticeably appear of a conductive function. One of the reasons is the lack of comprehension In compounding a carbon black with polymer rosins. This paper involves the understanding of compounding technology of the conductive carbon black filled composite. Our experimental results indicate that the fibrous shaped carbon black was hard to process but appeared of a superior conductivity compared to a stick or a sphelulite shaped carbon black. Therefore, it was processed with a processing oil in compounding, which led to a better processability and a better conductivity. This study was accomplished that the solution process compared to the melting process.

• Composites Research
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• v.16 no.2
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• pp.48-53
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• 2003

This paper presents a study on the permittivities of the I-glass fabric/epoxy composite laminates containing carbon black dispersions at microwave frequency. Measurements were performed at the frequency band of 5 GHz∼18 GHz. The results showed that the complex permittivities of the composites depend strongly on the natures and concentrations of the carbon black dispersion. A new scheme is proposed to obtain a mixing law for the estimation of the complex permittivities of the composite laminates as a function of concentration of carbon black. Simultaneously, the complex permittivity of carbon black itself was also calculated by the scheme. The experimental values of the complex permittivities of the composites were compared to those calculated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1089-1090
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• 2011

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.13.1-13.1
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• 2009

에어로젤은 인류가 개발한 소재 중에서 가장 가벼운 고체로, 기공률이 90%이상이고 비표면적은 ~1000m2/g, 기공의 크기는 10nm 크기로 이루어진 나노기공 물질이다. 1931년에 Kisley가 물유리로부터 실리카 에어로젤을 합성한 이래로 실리카 에어로젤에 대한 연구가 가장 많이 이루어져왔으며, 단열소재, 흡음재, 체렌코프우주선 디텍터, 반도체의 초저유전소재, 유출된 석유의 정제, 촉매 등에 대한 응용에 대해서도 연구가 많이 이루어져 왔다. 그리고TiO2와 같은 광촉매 에어로젤 소재, 카본 에어로젤 소재등 다양한 나노기공 소재에 대해서도 연구가 이루어지고 있으며, 카본 에어로젤의 경우 나노기공과 비표면적을이용한 전기이중층 커패시터 (EDLC)에 대한 연구도 이루어지고 이다. 본 연구에서는 첫째로, 실리카 에어로젤에 대한 연구결과를 소개하고 이의 단열소재로서의 응용가능성에대하여 언급하고자 한다. 실리카 에어로젤 나노기공 소재의 경우, 기공크기가 10nm크기로 매우 작고 공기의 자유이동길이와 거의 비슷하여서 대류에 의한 열전달을 낮출 수 있으며, 낮은 고체함량으로 인하여 포논에 의한 열전달을 낮출 수 있기 때문에 단열소재로서 최고의 성능을 나타낸다. 하지만, 문제는 높은 기공률로 인한 기계적인 취약성이 문제이다. 따라서 이를 보완하기 위항 섬유로 에어로젤을 보강할 수 있는데, 이를통하여 에어로젤 나노기공소재와 섬유보강에 의한 복합화에 대하여 말하고자 한다. 또 다른 하나의 연구방법은유기-무기 하이브리드 나노기공 소재를 합성하는 것이다. 여기서는하나의 방법으로 MTEOS-TEOS의 하이브리드화와 초임계 건조공정에 의한 나노기공 소재에 대한 연구결과를소개하고자 한다. 마지막으로 카본 에어로젤 나노기공소재의 합성과 나노기공 구조의 제어 및 물성평가에 대한 것을 말하고자하는데, 본 발표에서는 레소시놀과 포름알데히드를 촉매에 의한 중합반응을 통하여 유기 에어로젤 소재를 합성하고 분위기에서탄소화 공정을 통하여 카본에어로젤을 합성하였다. 또한 금속 니켈을 도입하는 것에 의하여 탄소/니켈 복합 하이브리드 에어로젤 소재를 합성하고 슈퍼커패시터 전기화학 특성에 대한 연구결과를 발표하고자 한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.482-488
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• 2019

Leisure and business facilities have been steadily developing in Korea. Among waterborne leisure vessels and equipment, the distribution and sale of kayaks and canoes have significantly increased. Previously, (FRP) materials were primarily employed for constructing kayaks. However, owing to global warming and depletion of natural resources, the demand for non-polluting renewable energy is rapidly increasing, which has increased the demand for carbon fibers. To meet the requirements of changing social consciousness, a carbon fiber-based commercial kayak was designed in this study. Resistance analysis and structural safety were conducted by employing software tool for verifying the reliability of the proposed kayak. The pressure resistance and frictional resistance were examined in a wide range of speed. Obtained results indicate that at speeds greater than 2.6 m/s, the pressure resistance significantly increases and the total resistance also increases. Furthermore, the results corroborate that the proposed kayak structure has a adequate safety with respect to the design loads that are considered during operating conditions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.05a
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• pp.23-29
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• 1995

Fafbric 4종, 수지2종과 상용화된 프리프레그 2종에 대한 내열특성에 관하여 비교 연구 하였다. Fabric의 특성은 알려진 바와 같이 PAN계 카본 fabric의 경우 내삭마성은 우수하나 단열성능이 떨어지고, Rayon계의 경우는 그 반대이다. 공정성면에서는 rayon spun yarn으로 제직한 경우가 가장 우수한 것으로 나타났다. Spun PAM으로 제직한 경우는 직조후 탄화공정을 채택함으로써. 노즐재료로서 PAN계 탄소섬유의 사용을 가능하게 하였지만 즉 공정성은 좋으나 단열성 및 내삭마성 모두가 떨어졌다. F940수지의 경우는 SC1008과 페놀수지의 화학적특성은 다소 차이가 있으나 물리적특성이나 열적특성은 거의 유사한 것으로 나타났다. 프리프레그의 제조는 각수지와 Fabric의 조건에 맞게 R/C, V/C를 조정하여 코팅하였다. 토오치 테스트등 결과들을 종합해보면 전체적인 노즐재료로서의 성능은 아직은 Rayon계 카본이 우수한것으로 판단할수 있으나, 보다 정확한 평가를 위해서는 실제 노즐 테스트가 필요하다.

• Polymer(Korea)
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• v.28 no.4
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• pp.285-290
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• 2004

Nondestructive damage sensitivity of carbon nanotube(CNT) and nanofiber (CNF)/epoxy composites with their adding contents was investigated using electro-micromechanical technique. Carbon black (CB) was used only for the comparison with CNT and CNF. The fracture of carbon fiber was detected by acoustic emission (AE), which was correlated to the change in electrical resistance, ΔR under double-matrix composites (DMC) test. Stress sensing on carbon nanocomposites was performed by electro-pullout test under uniform cyclic loading. At the same volume fraction, the damage sensitivity for fiber fracture, matrix deformation and stress sensing were highest for CNT/epoxy composite, whereas for CB/epoxy composite they were the lowest among three carbon nanomaterials (CNMs). Damage sensitivity was correlated with morphological observation of carbon nanocomposites. Homogeneous dispersion among CNMs could be keying parameters for better damage monitoring. In this study, damage sensing of carbon nanocomposites could be evaluated well nondestructively by the electrical resistance measurement with AE.

• Composites Research
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• v.18 no.6
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• pp.1-8
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• 2005

The fiber-reinforced composite materials have been advanced for various applications because of their excellent mechanical and electromagnetic properties. On their manufacturing processes, however, thermo-curing inherently produces the undesired thermal deformation mainly from temperature drop from the process temperature to the room temperature, so called spring-back. The spring-back must be understood especially in the hybrid composites in order to design and fabricate desired shape. In this research, (glass fiber / epoxy) + (carbon fiber / epoxy) unsymmetric hybrid composites were fabricated under various conditions such as cure cycle, laminate thickness, stacking sequence and curing sequence. Coupons were made and spring-back were measured using coordinate measuring machine (CMM). Using the Classical Lamination Theory (CLT) and finite element analysis (ANSYS), the behavior of spring-back were predicted and compared with the experimental data. The results from CLT and FEA agreed well with the experimental data. Although, the spring-back could be reduced by lowering curing temperature, at any case, the spring-back could not be removed completely.