• Bulletin of the Korean Chemical Society
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• 제17권3호
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• pp.245-253
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• 1996

A topological theory has been introduced to explain and evaluate the fractional volumes of system materials, the change of the weight and concentration of monomer molecules, molecular weight distribution, and interaction functions of polymer-polymer and polymer-oligomer, etc. for dispersion polymerization. The previous theory of Lu et al. has offered only an incomplete simulation model for dispersion polymer systems, whereas our present one gives a general theoretical model applicable to all the polymerization systems. The theory of Lu et al. considered only the physical property term caused by interaction between matters of low molecular weight (i.e., diluent, monomer, and oligomer) and polymer particles without dealing with physical properties caused by the structure of polymer networks in polymer particles, while our theory deals with all physical effect possible, caused by the displacement of not only entangled points but also junction points in polymer particles. The theoretically predictive values show good agreement with the experimental data for dispersion polymerization systems.

• Bulletin of the Korean Chemical Society
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• 제16권11호
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• pp.1046-1056
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• 1995

A topological theory has been introduced to evaluate the degree of complexation and the viscosity of polymer complexes by extending the theory of Iliopoulos and Audebert for aqueous polymer solutions. The previous theory of Iliopoulos and Audebert has offered only a semiquantitative theoretical model for polymer complex systems, whereas our present work gives a general theoretical model applicable to all the polymer complex systems. Their theories considered only the physical property term caused by the displacement of complexed points between polymer solute chains, while our theory deals with all the physical effects, caused by the displacement of complexed points entangled points in polymer solute chains. There have been predicted the characteristics of physical properties from the expression. It is exposed that the predictive values show good agreement with the experimental data for polymer complexes.

• 멤브레인
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• 제27권3호
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• pp.255-262
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• 2017

본 연구에서는 graphene oxide (GO)를 polyacrylonitrile (PAN)에 첨가하여 전기방사법을 이용해 나노섬유 복합막을 제조한 뒤 물리적 특성을 관찰하였다. GO의 제조는 개선된 Hummer's 방법을 이용하였으며, 표면처리가 되지 않은 GO의 경우 0.5 wt% 이상에서 전기방사가 이루어지지 않았다. GO의 안정성 및 분산도 증가를 개선하기 위해 계면활성제를 이용하여 GO의 표면처리를 하였다. 표면처리가 된 GO를 사용하여 나노섬유 복합막의 GO의 함량을 0.5 wt% 이상 첨가할 수 있었다. 특히, 표면처리가 된 GO가 첨가된 나노섬유 복합막은 향상된 물리적 특성을 가지며, 이는 나노섬유 분리막 내의 GO의 분산도와 상관관계가 있는 것으로 보인다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1998년도 가을 학술발표회논문집
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• pp.29-32
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• 1998

Segmented block copolyetheresters defined as copolymers having sequences of alternating polyester hard blocks and polyether soft blocks create labile physical cross-links upon crystallization of hard polyester blocks Since the nature of the physical interlocking is a crystallite formed exclusively from the crystallizable hard segment, the basic understanding of interrelationship between crystallization condition and phase morphology is very important for the property control of the segmented block copolyetheresters. (omitted)

• 자원환경지질
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• 제22권2호
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• pp.129-139
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• 1989

The anthracite coalfields of Korea are confined to the areas where sedimentary rocks of Permian and Jurassic are preserved. The Chungnam coalfield lies in the sedimentary rocks of Jurassic which belongs to the Daedong Supergroup (the Nampo group). For the property analysis of each coal seam interbeded in Daedong Supergroup, Seongju area is chosen and twelve coalseams are taken. Many standard tests have been established for optical analysis (maceral analysis, coalification degree measurement), chemical analysis (proximate, ultimate analysis) and physical analysis (ignition temperature, ash fusion temperature, hardgrove grindability index and X-ray diffraction). The Jurassic anthracite mainly consist of vitrinite and macrinite and the range of the reflectance is $R_{max}$ 5.0-6.5 which means metaanthracite rank. By the chemical composition analysis, it shows low H/C and high O/C value compare with international average value. By the physical analysis, it has very high ignition temperature ($531-584^{\circ}C$) and ash fusion temperature ($1510-1700^{\circ}C$) and very low combustion velocity (0.2-1.9 mg/min). The very wide range of the hardgrove grindability index (46-132) means that the grindability controlled mainly by the structural conditions of coal bearing strata.

• 폴리머
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• 제37권6호
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• pp.770-776
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• 2013

낮은 기체투과성을 보이는 epoxidized natural rubber 50(ENR 50)에 매우 낮은 기체투과성을 가지고 있고 마모 특성이 우수한 Nylon 6를 이축형 압출기를 사용해서 블렌드하였다. 혼합물의 기계적 물성과 기체차단성이 향상되는 효과를 얻었으나 ENR 50 매트릭스상에 Nylon 6의 분산성이 떨어져 큰 상승효과를 보이지는 않았다. 따라서 Nylon 6의 분산성을 개선하기 위해 ENR 50에 maleic anhydride(MAH)를 그래프트시켰다. MAH와 ENR 50간의 그래프트 반응은 FTIR 스펙트럼을 통해서 확인할 수 있었다. ENR 50-g-MAH/Nylon 6 배합물을 제조함으로 인해 기체차단성, 기계적 물성이 MAH를 사용하지 않았을 때보다 향상시킬 수 있었다. MAH의 그래프트 비율을 최대로 높인 5 phr을 첨가하였을 때 가교밀도가 높았으며 가장 좋은 물성을 보였다.

• Elastomers and Composites
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• 제39권4호
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• pp.286-293
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• 2004

경도를 달리하는 에스테르계 및 에테르계 열가소성 폴리우레탄(thermoplastic polyurethane: TPU)의 사출에서 금형 온도가 물리적 성질에 미치는 영향을 조사하였다. TPU의 연질부 유리전이온도는 금형 온도 변화에 따라 거의 변화하지 않았으며, 연질부와 경질부의 상분리는 금형온도의 영향을 별로 받지 않는 것으로 판단되었다. 그러나 에스테르계와 에테르계 TPU는 종류에 관계없이 공통적으로 경도가 높은 TPU들은 금형온도를 높이는 경우 결정성, 고무상 평탄 온도영역, 인장강도가 감소하였으나, 경도가 낮은 TPU들은 오히려 결정성, 고무상 평탄 온도영역, 인장강도의 증가를 보였다. TPU의 사출 성형 금형 온도에 따른 물리적 성질의 차이를 결정성 경질부의 결정화와 물리적 가교효과 차이로 해석하였다.

• 한국식품과학회지
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• 제21권6호
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• pp.851-856
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• 1989

추출방법을 달리하여 얻은 육두구 정유에 대한 물리적 성질을 측정하고, GC와 GC/MS를 이용하여 분석하였다. 추출수율은 용매추출이 23%로 가장 많았고 SDE 추출, $CO_2$ 추출순이었다. 육두구유에 대한 물리적 성질과 GC분석결과에서 본 실험에 사용한 육두구는 East Indies type에 가까운 것을 확인할 수 있었고 각각 추출물의 분석결과로부터 sabinene은 3.6-14.1%, miristicin은 28.4-48.7% elemicin은 1.2-2.1%이 함유되어 있음을 알 수 있었다. 또 발암물질로 알려진 safrole은 SDE 추출에서 3.8%, 용매추출에서 3.6%, $CO_2$추출에서 5.6% 함유하고 있는 것으로 나타났다. SDE 추출이나 용매추출에서 확인된 camphene은 $CO_2$추출에서 확인할 수 없었고 monoterpene, terpene alcohol 계통의 화합물은 SDE 추출이나 용매 추출에 많았다. 방향족 화합물은 $CO_2$추출에서 많이 추출됨을 확인할 수 있었다.

• 한국작물학회지
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• 제50권2호
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• pp.120-124
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• 2005

Expanded rice husk (ERR) is different from commercial rice seedling media in chemical and physical properties such as pH, permeability, and water content. This study was conducted to test a possibility of improving rice seedling growth by improving the texture of ERR as a rice seedling medium. The seedling media used were a commercial seedling medium (CSM), rice husk, and ERR 1, 2, 3, and 4 with different expansion degrees. The pH of the ERHs ranged from 6.3 to 6.8. As the expansion rate increased, ERR particle sizes decreased, and water permeability and absorption rates improved. No significant differences in shoot dry weight and rate of maturity were found among the seedlings cultivated in the different ERH media. However, the mat formation of seedling roots became loose as the expansion rates were decreased. Further studies are necessary to determine the cause of poor root growth in ERH media.

• 대한조선학회논문집
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• 제40권1호
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• pp.55-62
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• 2003

This study has investigated physical and chemical properties of FRP waste, has manufactured polymer cement mortar using a crushed waste with sand and has evaluated its capability to develop the economical waste recycling technology. The study has investigated tension strength, hardness test and impact test as physical properties and also thermogravimetric characteristics and analyzed infrared spectroscope as chemical properties. Then the study has manufactured polymer cement mortar and has analyzed how the FRP waste fine aggregate replacement ratio has an effect on compression strength. Noticing admixture can complement strength drop occurred by the FRP waste fine aggregate replacement, the study examined an optimum rate of admixture addition and its reaction through electron microscope photos.