• 한국염색가공학회지
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• 제22권3호
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• pp.246-256
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• 2010

This study studies on the physical property of MWNT/PU composite film for electrostatic dissipation (ESD) function by dispersing multi-wall carbon nanotubes (MWNT) in dimethylformamide (DMF) and by combining it with polyurethane(PU). For this purpose, four kinds of MWNT were selected and the composite films were made by dispersion processing, and their physical properties were measured and investigated in terms of electrical conductivity. For dispersion parameters, four MWNT contents(0.5, 1, 2, 5wt%) and two dispersion times(30min, 120min) were selected. The dispersion property and the electrical conductivity of MWNT/PU film was measured using a UV-Vis spectrometer and conductivity measuring apparatus. Finally, their physical properties according to the dispersion conditions were analyzed and discussed with various processing conditions.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.33-36
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• 2003

AC and DC conductivity of the MWNT(Multi walled nanotubes)/polyurethane composites were investigated with respect to the various oxidative conditions, where these means acid concentration, treatment temperature, and treatment time. We suppose that the conditions of oxidation of the MWNTS have a certain influence on the degree of functionalization, damages, and dispersion of the MWNT themselves. Futhermore, the electrical properties of the resulting composites strongly depend on the oxidative conditions of MWNTS. The conductivity of the composites produced by using the optimal condition was measured as a function of frequency with volume content of MWNTS. These experimental results were analyzed using percolation theory Electromagnetic interference shielding effectiveness (SE) of the mixtures of polyurethane (PU), optimized MWNTs, and silver (Ag) is measured in the frequency range from 10 MHz to 6 ㎓ by using ASTM D4935-89. The measured SEs of the mixtures could be controlled from about 55 dB to 85 dB with the compositions of Ag/MWNT and compounding methods(C1, C2).

• Macromolecular Research
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• 제11권3호
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• pp.198-201
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• 2003

Aqueous emulsion of polyurethane (PU) ionomers were reinforced with hydrophobic nanosilica to give composites. The aqueous emulsion was stable and the particle size increased as the content of hydrophobic nanosilica was increased. The reinforcing effect of nanosilica in mechanical properties of these composites were examined by dynamic mechanical and tensile tests, and the Shore A hardness was measured. Enhanced thermal and water resistance and marginal reduction in transparency of these composites were observed compared with pristine polymer. These results were similar with those of our previous studies on waterborne PU/organoclay nanocomposites.

• 전기학회논문지
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• 제61권9호
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• pp.1362-1367
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• 2012

High porous silica aerogel/polyurethane polymer composite was manufactured by cross-linking polymerization of polyurethane foaming process. The properties of microstructure, mechanical strength, and thermal properties were investigated for its various applications. The superhydrophobic silica aerogel powders were used for highly thermal insulation filler materials. The thermal conductivities can be resulted 0.07 W/mK to 0.13 W/mK, by decreasing the contents of silica aerogels in composite materials. It is found that the polymerization formulation by organic binders can be applied to heavy industires, building materials, and various industries.

• 한국염색가공학회지
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• 제22권4호
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• pp.362-372
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• 2010

This paper surveys the physical properties of the multiwall carbon nanotube (MWNT) and polyurethane composite film for improvement of mechanical properties and electrical characteristics. The modification of MWNT was carried out by acid treatment with nitric and sulphuric acid mixed solution, and then followed by thermal treatment for enhancing MWNT dispersion with polyurethane. This modified MWNT was mixed with polyurethane by changing the loading content of MWNT and dispersion time under the dimethylformamide solution in the ultrasonic wave apparatus. Various physical characteristics of the modified PU/MWNT films were measured and analyzed in terms of the loading content and dispersion time. The maximum absorbance of the PU/MWNT films were observed with the 2wt% loading at dispersion times of 2 and 24 hour, respectively. The minimum electrical volume resistivity of PU/MWNT film was shown at the loading content of 0.5wt% or more irrespective of dispersion treating time. However the optimum condition was assumed to 2wt% loading at dispersion time of 2 hours by assessing the surface profile of the film using video microscope. The breaking stress and strain of the PU/MWNT film decreased with increasing loading content, but no change of physical properties was shown with increasing in dispersion time.

• Composites Research
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• 제33권2호
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• pp.50-54
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• 2020

소프트 로봇 및 웨어러블 소자는 대변형 및 큰 유연성을 요구한다. 이에 따라, 소프트 로봇 또는 웨어러블 소자에 부착하여 사용할 수 있는 신축성 스트레인 센서의 필요성이 대두되고 있다. 본 연구에서는 폴리우레탄과 은나노꽃입자를 혼합하여 신축성과 전기전도성을 갖는 복합 섬유를 제조하였다. 이러한 복합 섬유는 스트레인에 따라 섬유의 저항이 변하게 되어 신축성 스트레인 센서로 가능성이 높다. 복합 섬유를 신축성 스트레인 센서로 활용하기 위해서, 복합 섬유의 기계적, 전기적 특성을 측정, 분석하였다.

• Elastomers and Composites
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• 제58권3호
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• pp.112-120
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• 2023

Herein, we propose a facile water-processible method to develop an eggshell membrane (ESM)-embedded waterborne polyurethane (WPU)-based bio-degradable and bio-compatible coating material that exhibits attractive tactile properties. Virgin ESM is not dispersible in water. Hence, to develop the ESM-based WPU composite, soluble ESM (S-ESM) was first extracted by de-crosslinking the ESM. The extracted S-ESM at different concentrations (0, 0.5, 1.0, 1.5 wt %) was mixed with WPU. Compared to virgin WPU, the viscosity of S-ESM/WPU dispersion and the in-plane coefficient of friction (COF) of the composite film surfaces decreased with an increase in the S-ESM content. In addition, an increase in the S-ESM content improved the tribo-positive characteristics of the film. Different good touch-feeling biomaterials, such as fur, feather, and human skin exhibit tribo-positivity. Thus, the enhanced tribo-positive characteristics of the S-ESM/WPU and the decrease in their COF owing to an increase in the S-ESM content imply the enhancement of its touch-feeling performance. The S-ESM embedded WPU composites have potential applications as coating materials in various fields, including automobile interiors and artificial leather.

• 폴리머
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• 제36권6호
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• pp.721-726
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• 2012

해수에서 사용되는 음향 소나 시스템의 호스 소재로 열가소성 폴리우레탄 탄성체가 사용되고 있다. 장기간 소나 운용을 위해서는 향상된 기계적 물성과 해수 및 오일에 의한 낮은 팽윤도를 갖는 소재가 요구된다. 해수 적용에 적합한 향상된 물성의 복합재료를 개발하기 위해 실리카 나노입자 표면에 폴리우레탄을 그래프트시킨 TPU-g-silica 나노입자를 제조하고 이를 폴리우레탄과 혼련하여 복합재료를 제조하였다. 실리카 나노입자를 포함한 폴리우레탄 복합재료는 실리카 입자의 표면 처리에 상관없이 폴리우레탄보다 향상된 인장강도와 낮은 팽윤도를 나타내었다. 폴리우레탄 복합재료들이 같은 함량의 실리카 입자를 포함한 경우, TPU-g-silica를 포함한 복합재료가 표면처리를 하지 않은 실리카 입자를 포함한 복합재료에 비해 보다 향상된 인장강도와 낮은 팽윤도를 나타내었다. 장시간 오일에 함침 후 인장강도를 측정한 결과 폴리우레탄에 비해 TPU-g-silica를 포함한 복합재료가 높은 인장강도를 유지하였다.

• 한국가스학회지
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• 제7권1호
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• pp.28-32
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• 2003

대체 facing material 소재로 유력시되는 FRP를 사용하여 facing material이 갖추어야할 압축, 인장 등 기계적 물성과, vapor barrier도, 화학적 안전성 등을 조사한 결과 모든 면에서 기존의 plywood보다 우수한 성질을 나타냄을 밝혔다. 본 연구의 결과로서 대체 facing material로 FRP를 사용할 경우 LNG 저장 탱크의 안전성이 향상되고 높은 vapor barrier기능으로 인해 탱크의 성능이 향상되는 등 다양한 장점을 나타냄을 알 수 있게 되었다. 따라서 본 연구의 결과는 LNG 저장 탱크의 성능을 개선하는데 기여하며, LNG 저장 탱크용 합판의 대체연구에 적극적으로 활용될 수 있을 것으로 사료된다.

• 한국산학기술학회논문지
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• 제13권3호
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• pp.955-960
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• 2012

본 연구는 순수 Polyurethane과 일반적인 난연제인 $Al(OH)_3$ 및 $Mg(OH)_2$를 첨가한 sample과 Cloisite Na+, Cloisite 15A를 첨가한 sample의 난연성 및 기계적 특성을 비교하였다. 또한 Sodium silicate와 Polyurethane을 혼합한 것에 경량성 충진제인 Vermiculite, Perlite를 충진한 sample의 난연성 및 기계적 특성을 확인하였다. 그 결과, Cloisite Na+와 Cloisite 15A를 첨가한 sample과 Sodium silicate를 혼합한 sample에서 난연제를 첨가한 것과 같은 등급의 난연성을 확인하였다. 인장강도는 filler의 양이 증가함에 따라 저하 되었으나, sodium silicate를 첨가한 sample의 경우 다른 sample 보다 강도가 향상됨을 확인하였다.