• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.59-65
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• 1998

Morphology and thermal properties of polyurethane synthesized from 4,4'-diphenylmethane diisocyanate (MDI), polyester polyol, and 1,4-butane diol are investigated using fourier transform infrared spectroscopy (FT-IR), differential scanning calorimeter (DSC), and dynamic mechanical thermal analysis (DMTA). From the FT-IR study, it is found that the stretching peaks of hydrogen bonded N-H and C=O are shifted to the low frequencies with the increase of hard segment content of the polyurethanes. The shift of the stretching peaks of hydrogen bonded N-H and C=O indicates that the degree of hydrogen bonding is increased. From the DSC study, it appears that the glass transition temperature ($T_g$) of the polyurethanes is increased with the increase of the hard segment content. Also, it is found that the polyurethanes investigated in this study have the homogeneous network structure due to the high functionality of the MDI. From the DMTA study, transition of the soft segment was not found. Therefore it is concluded that the polyurethanes investigated in this study have the one-phase morphology which is consistent with the DSC results.

• Polymer(Korea)
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• v.38 no.6
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• pp.714-719
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• 2014

Bio-based nylon 6-morpholinone random copolymers were prepared by the anionic ring opening polymerization of ${\varepsilon}$-caprolactam and morpholinone, both of which were prepared from lysine and glucose, respectively. From this work, a new biomass based nylon 6 with improved hydrophilicity was prepared. Optimizing the polymerization condition, copolymer with a viscosity-average molecular weight of 30000 g/mol was prepared, with a yield of 80%. It was possible to improve the hydrophilicity of nylon 6 by its copolymerization with morpholinone. The prepared nylon 6-morpholinone random copolymers were then characterized using several analytical methods such as DSC, TGA, XRD, viscosity measurement with U-shaped glass capillary viscometer and contact angle measurement.

• Polymer(Korea)
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• v.37 no.4
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• pp.547-552
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• 2013

Polyimide (PI) containing carboxyl functional group was prepared and reacted with diaminosiloxane during high temperature film casting. The morphology of resulting film was observed by using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX), which revealed that globular 100 nm-sized PI domains and continuous polysiloxane phase were formed. X-ray photoelectron spectroscopy (XPS) study indicated that air-film interface mainly consisted of polysiloxane blocks. Poly(imidesiloxane) thin layer was thermostable until $400^{\circ}C$ and its pressure- sensitive adhesive property was retained up to $300^{\circ}C$. The comparative experiments revealed that grafting between carboxyl groups of polyimide and aminosiloxane was crucial for formation of microdomain structure and pressure-sensitive adhesive property.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.705-708
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• 2004

과거 로(low)-폴리곤 3D 메시는 모델러에 의해 각 정점들의 제어가 가능했지만, 앞으로의 대세가 전망되는 하이-폴리곤의 경우 모든 정점들을 일일이 제어하는 것은 불가능하다. 따라서 하이-폴리곤 3D 메시는 넙스로 구성될 것이다. 본 연구는 이러한 하이-폴리곤 3D 메시가 스킨 애니메이션될 때 하이-폴리곤 3D 메시의 넙스 구조와 넙스의 계산 속도를 개선하여 애니메이션의 속도를 향상시키는 것을 연구하였다. 본 연구의 결과는 3D 애플리케이션에서 애니메이션을 사용할 때, 하이-폴리곤일수록 애니메이션 연산이 증가하는 것을 억제하고 하이-폴리곤을 사용하는 애니메이션의 부담없는 사용과 넙스의 LOD 적용을 실시간에 가능하게 한다.

• 대학교육
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• s.99
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• pp.8-9
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• 1999

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.83-83
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• 2018

최근 매실나무를 기주로 한 겨우살이의 인공재배에 성공함에 따라, 식 의약품과 화장품의 소재 및 산업화 가능성을 확인하기 위해 80% 에탄올 및 증류수 초음파추출물의 총 폴리페놀 플라보노이드 함량 및 DPPH free radical 소거능을 측정하였다. 경기도 남양주시에서 인공재배한 매실나무겨우살이(동결건조) 및 강원도 홍천에서 채취한 자연산 굴참나무겨우살이(열풍건조, $30^{\circ}C$, 7day)의 80% 에탄올, 증류수 초음파추출물에 대한 총 폴리페놀 및 플라보노이드함량 그리고 DPPH free radical 소거능을 측정한 결과, 시료의 농도에 비례하여 총 폴리페놀과 플라보노이드 함량 그리고 DPPH free radical 소거능이 증가하였다. 총 폴리페놀 함량은 매실나무겨우살이의 80% 에탄올 추출물이 5,000ppm에서 $192.63{\mu}g/ml$로 가장 많았으며, 굴참나무겨우살이의 물 추출물이 100ppm에서 $4.86{\mu}g/ml$로 가장 낮고 매실나무겨우살이가 모든 용매에서 더 많은 폴리페놀을 함유한 것으로 확인되었다. 총 플라보노이드 함량은 굴참나무겨우살이의 80% 에탄올 추출물이 5,000ppm에서 $83.59{\mu}g/ml$로 가장 높았으며, 매실나무겨우살이 물 추출물이 $4.6{\mu}g/ml$로 가장 낮았고 굴참나무겨우살이가 모든 용매에서 더 많은 플라보노이드를 함유한 것으로 확인되었다. DPPH free radical 소거능은 80% 에탄올 추출물 5,000ppm에서 매실나무겨우살이 81.75%로 시료 중 가장 높았고, 굴참나무겨우살이 물 추출물 100ppm이 3.55%로 가장 낮음을 확인할 수 있었다. 본 연구 결과에 따르면, 겨우살이를 초음파추출법으로 추출할 때, 80% 에탄올 초음파추출물이 더 많은 폴리페놀을 함유하여 80% 에탄올 추출물이 물 추출물보다 비교적 적합하였다. 80% 에탄올로 초음파추출 하였을 때 동결건조 한 매실나무겨우살이가 열풍건조한 자연산 굴참나무겨우살이보다 더 많은 폴리페놀을 함유하고 있고, 더 높은 DPPH free radical 소거능을 보여줌에 따라 식 의약품 그리고 화장품의 소재화 및 산업화의 가능성이 높음을 확인할 수 있었다.

• Journal of the Korean Applied Science and Technology
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• v.29 no.3
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• pp.531-542
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• 2012

The thesis covers the trend of research on bio-based polyurethane which is made from polyols derived mainly from plant oils and isocyanates. Castor oil is a triglyceride of ricinoleic acid containing hydroxyl group. Hydroxylation is done on the unsaturated bonds of the oils by the reactions of epoxidation/ring opening, hydroformylation/hydrogenation, ozonolysis/hydrogenation, and thiol-ene reaction. Polyols from hyperbranch, primary alcohol, polysaccharide have been studied to control the reactivity of the polyol and morphology of the microdomains. Besides, researches cover biodegradable polylactic acid polyol for medical use, fatty acid dimer polyol for the prevention of hydrolysis, and polyol with ionic group for water-borne polyurethane. Bio-based polyurethanes are being used in flexible and rigid foams, coatings, sealants, and elastomers.

• Journal of Adhesion and Interface
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• v.5 no.1
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• pp.29-35
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• 2004

We have prepared polyster/nanQhybridized polyimide films in the range of 1~9 wt% of organophilic synthetic layered silicate (STN). Firstly, poly(amic acid)/STN nanocomposite solutions were prepared via solution blending method in DMAc or THF/MeOH solution, and then cast on the polyester film followed by imidization reaction, thermal and chemical method repestively. XRD and TEM experiment showed that the STN was fully exfoliated through the polyimide matrix. Surface morphologies of nanohybridized polyimide films were characterized by AFM and thermal, mechanical properties were also confirmed by TGA, DMA and UTM each. And also, the water vapor permeabilities highly depended on the content of STN. The sample from chemical imidization route and THF/MeOH solvent system showed better water vapor barrier properties than thermal one and DMAc system.

• Proceedings of the Korean Fiber Society Conference
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• 1989.06a
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• pp.78-79
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• 1989

• The Korean Journal of Rheology
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• v.6 no.2
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• pp.147-156
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• 1994

폴리프로필렌 이산화티타늄 첨가 폴리프로필렌을 심초형 복합 방사하여 첨가제를 섬유의 중심부분, 또 표면부분에 차별분포시켰다. TiO2의 함량이 증가함에 따라 점도(η)와 저장탄성계수(G＇)는 증가하였다. 전자현미경으로 파단면의 모폴로지를 관찰한 결과 TiO2와 함량이 증가함에 따라 감소하는 경향을 보였다. TiO2의 함량 증가에 따라 강력, 절단신도, 그리고 탄성계수는 감소하였다. 복합방사한 섬유의 TiO2 함량이 2% 미만일 때는 homo PP 보다 강력이 좋아졌다. 복합 섬유의 탄성계수는 중심부에 homo PP가 분포한 경우가 더 컸 고 강력과절단 신도는 중심부에 filled PP가 분포한 경우가 더 컸다.