• 한국안전학회지
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• 제20권4호
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• pp.63-70
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• 2005

It has been used so many kinds of architectural materials and interior products in current building construction, and use of composite architectural materials is increasing with the development of chemical technology. As the green architecture has become the center of public interest, much effort is conducted in advanced countries on the LCA point of view, such as restriction of architectural materials that emitting pollution substances, developing of Non-Toxic architectural materials, and recycling of used materials, etc. with the cooperation of related organizations, material manufacture companies, and construction companies. Because the kinds of materials to be used in building constructions are so various, there might be some possibility of personal and subjective choice at the time of materials selection resulting the missing the requirements of building components and the choice of harmful materials to human. One way to resolve the material problem is to present the green architectural materials which coincide with the quality performance at service and not harmful to man and nature. At this point of view, this study aims to develop the material classification model by investigating the major labelling system about green architectural materials in both domestic and abroad and to implement an efficient material selection system by making a powerful database of environmental standard and quality basis of building requirements.

• 대한금속재료학회지
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• 제50권5호
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• pp.401-406
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• 2012

When viewed using a magnetic resonance imaging (MRI) system, invasive materials inside the human body, in many cases, severely distort the MR image of human tissues. The degree of the MR image distortion increases in proportion not only to the difference in the susceptibility between the invasive material and the human tissue, but also to the intensity of the magnetic field induced by the MRI system. In this study, by blending paramagnetic Ti particles with diamagnetic graphite, we synthesized $Ti_{100-x}C_x$ composites that can reduce the artifact in the MR image under the high-strength magnetic field. Of the developed composites, $Ti_{70}C_{30}$ showed the magnetic susceptibility of ${\chi}=67.6{\times}10^{-6}$, which corresponds to 30% of those of commercially available Ti alloys, the lowest reported in the literature. The level of the MR image distortion in the vicinity of the $Ti_{70}C_{30}$ composite insert was nearly negligible even under the high magnetic field of 4.7 T. In this paper, we reported on a methodology of designing new structural materials for bio-applications, their synthesis, experimental confirmation and measurement of MR images.

• 한국건축시공학회지
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• 제19권1호
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• pp.19-29
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• 2019

본 연구에서는 공동주택 지하주차장 상부슬래브 등 주로 수평부에 적용되는 아스팔트 매스틱 도막재의 누유하자 원인을 바탕으로 제품의 누유안정성 확보 여부를 평가할 수 있는 평가방법을 개발 및 제시하였다. 본 연구에서 제시한 평가방법의 신뢰성을 검증하기 위하여 실제 현장에서 누유 발생 이력이 있는 3개 제품을 대상으로 누유안정성 평가를 진행하였으며, 진행 결과, 실제 발생하는 누유하자의 재연이 가능한 것으로 확인되었다. 재연성에 대한 정량적 검증을 위해 평가 중에 발생한 누유 시료를 채취하여 회분(Filler)함량을 측정한 결과, 정상시료 대비 최대 약 64%가 저하된 것을 확인하였는데, 이는 선행연구에서 규명한 누유원인과 일치하는 결과로 확인하여, 평가방법의 신뢰성이 검증되었다 할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1297-1302
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• 2012

The interaction between carbon monoxide (CO) and a cobalt-salen complex (Co(salen)) was studied and applied to detect CO. The metal complex doped PEDOT:PSS film exhibited good sensitivity to CO and differentiate CO from other gases. The response of the composite to CO was reversible (RSD < 5%) change in resistance upon removal of CO gas from the test chamber. The effects of adding Co(salen) in the probe film on the response of the sensor were investigated using AFM, XPS, and FT-IR spectroscopy. The sensitivity of the sensor increased as the Co(salen) concentration enhanced as it increased from 0.0 to 1.5 wt. %, where the highest sensitivity ($%{\Delta}R/R_o$) of $-25.0{\pm}0.05%$ was achieved with 1.0 wt. % Co(salen). The sensor containing probe exhibited a linear response ($R^2$ = 0.983) in the range of 0.5 to 10.0% CO (v/v) $N_2$, and the detection limit was 1.74% CO (v/v) in $N_2$.

• Composites Research
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• 제36권5호
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• pp.297-302
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• 2023

발포체를 성형하기 위한 방법으로는 여러 가지 방법이 있는데 일반적으로 가장 많이 사용되는 방법으로는 발포제를 섞은 레진을 고온, 고압상태에서 발포하는 가압발포 방법과, 압을 주지 않은 고온의 상태에서 발포하는 상압발포 방법이 있다. 발포에 사용되는 고분자들은 상압상태에서 발포를 시키기 위해서는 최적 발포조건에 대한 설계 및 분석이 필요하다. 친환경 바이오 기반 폴리머는 단독으로는 발포가 힘든 문제가 있어 기존의 발포체 제조가 가능한 수지를 혼합하여 발포체를 제조하는 연구가 진행되고 있다. 본 연구에서는 바이오 기반 고분자의 함량 변화에 따른 바이오 기반 고분자와 EVA 혼합 발포체의 특성변화에 대해서 연구하였으며 가교도에 따른 최적 발포 조건에 대해서 연구하였다. 발포체의 기계적 특성 분석을 통해서 발포특성과의 상관관계에 대해서 연구하였다. 이 연구를 통해 바이오 기반 폴리머의 함량이 바이오 기반 폴리머가 포함된 발포체의 물성에 어떤 영향을 미치는지 알 수 있었고 상압 및 가압 발포 공정에 따른 차이점을 확인할 수 있었다. 또한, 바이오 기반 폴리머-EVA 복합 발포체의 상용화 가능성을 확인하였다.

• 문화기술의 융합
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• 제8권5호
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• pp.749-754
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• 2022

다양한 의료 응용 분야에서 웨어러블 및 피부 부착형 전자 패치에 피부 표면의 높은 접착력과 내수성이 요구된다. 본 연구에서는 탄소 기반 전도성 고분자 복합 소재에 개구리 발바닥의 육각 채널와 문어 빨판의 흡착 구조 패턴을 모사한 신축성 있는 전자 패치를 보고한다. 개구리의 발바닥을 모사한 육각 채널 구조는 수분을 배수하며, 균열억제 효과를 통해 점착력을 향상 시키며, 문어 빨판을 모사한 흡착 구조는 젖은 표면에서 높은 점착력을 나타낸다. 또한 고점착 전자패치는 실리콘(max. 4.06 N/cm²), 피부 복제 표면(max. 1.84 N/cm²) 등 다양한 표면에 건조 및 젖은 조건에서 우수한 접착력을 가지고 있다. 고분자 매트릭스와 탄소 입자를 기반으로한 고분자 복합소재를 통해 제작된 고점착 전자 패치는 건조 및 습한 환경에서 심전도(ECG)을 안정적으로 감지할 수 있다. 이 연구에서 보여진 특성을 기반으로 제안된 전자 패치는 다양한 생체 신호의 진단을 위한 웨어러블 및 피부 부착 센서 디바이스를 구현하는 잠재적 응용 가능성을 제시한다.

• Elastomers and Composites
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• 제56권3호
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• pp.136-151
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• 2021

Biomass lignin, a waste produced during the paper and bio-ethanol production process, is a cheap material that is available in large quantities. Thus, the interest in the valorization of biomass lignin has been increasing in industrial and academic areas. Over the years, lignin has been predominantly burnt as fuel to run pulping plants. However, less than 2% of the available lignin has been utilized for producing specialty chemicals, such as dispersants, adhesives, surfactants, and other value-added products. The development of value-added lignin-derived co-products should help make second generation biorefineries and the paper industry more profitable by valorizing lignin. Another possible approach towards value-added applications is using lignin as a component in plastics. However, blending lignin with polymers is not simple because the polarity of lignin molecules results in strong self-interactions. Therefore, achieving in-depth insights on lignin characteristics and structure will help in accelerating the development of lignin-based products. Considering the multipurpose characteristics of lignin for producing value-added products, this review will shed light on the potential applications of lignin and lignin-based derivatives on polymeric composite production. Moreover, the challenges in lignin valorization will be addressed.

• KSBB Journal
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• 제26권5호
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• pp.422-426
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• 2011

Alginate bead has been supplemented with various polymers to control permeability and to enhance mechanical strength. In this report, fibroin-reinforced alginate hydrogel was prepared, in which spatial localization of fibroin molecules was investigated. Confocal laser scanning microscopy revealed that fibroin molecules formed a fibrous network in the alginate-fibroin beads, which was expected to enhance mechanical strength as same as in many composite materials. Uniaxial compression test showed that fibroin-reinforced alginate beads had increased mechanical strength only after methanol treatment that caused ${\beta}$-sheet formation among fibroin molecules. Simultaneous curing and dialysis of alginate beads were carried out to remove excesscalcium but to retain fibroin in the dialysis chamber, which fabricated beads without internal fibrous fluorescent stains. Fibroin molecules were only found beneath the surface of the beads. The fibroin-diffused shell was further processed to form a thick wall after drying or was mobilizedto the centre of the bead by methanol treatment. Accordingly, the structure analyses provide processing methods of fibroin to form a wall or center clumps, which could be applied to design controlled delivery device.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.410-413
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• 2012

A traditional fabrication method is very difficult to make small robots using embedded sensors, actuators and connectors. Fortunately, Shape Deposition Manufacturing can provide an alternative method, and it has many benefits. Firstly, the weight of robot can be lighter, as it can be consisted of composite materials. Secondly, SDM can make simple robot structures because this approach does not need to use connectors and fasteners. Lastly, SDM gives stiffness and flexibility at the specific parts. Therefore, in this paper, we present a design of 3 segment legs organized by SDM, what the SDM approach is, and compare SDM method with 3 segment prototype legs which uses a traditional approach and made by DGIST.

• Korean Chemical Engineering Research
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• 제61권4호
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• pp.584-590
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• 2023

In this study, we focus on the recycling of cardboard waste and sugarcane bagasse (SCB) for the preparation of carboxymethyl cellulose (CMC) and its conversion into a biodegradable film. Sodium alginate (SA) was added to form a biodegradable composite film. SA was used to increase film permeability. Glycerol, which is a plasticizer, was used to increase the tensile strength (TS) and film expansion. To characterize the CMC, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used. The addition of olive oil to the CMC-SA matrix highlighted its antimicrobial property against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). A slight decrease in tensile strength was observed with the addition of olive oil (OO), which improved the functional properties of the control films as well as lowered moisture content and water solubility. But considering all other factors, the composite films obtained from sugarcane bagasse and cardboard waste incorporated with olive oil are suitable for applications in the field of food packaging.