• 폴리머
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• 제35권2호
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• pp.99-105
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• 2011

컴파운드의 물성을 최적화하기 위해서는 충전제 입자들의 분배와 분산이 잘 일어나도록 효율적으로 훈련하는 것이 중요하다. 혼련 효용을 향상시키고자 다양한 종류의 혼련 요소들이 이축압출기에 이용되고 있다. 본 연구에서는 탄산칼슘이 충전된 폴리스티렌을 대상으로 충전제 분산에 대한 이축압출기의 스크루 조합 영향을 알아보았다. 충전제의 분산 상태는 포토다이오드가 장착된 광학현미경으로 조사하였다. 실험 결과는 충전제의 분산 정도가 혼련 요소들의 형태 및 위치에 주로 영향을 받는다는 것을 보여주었다.

• 한국전기전자재료학회논문지
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• 제26권11호
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• pp.810-815
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• 2013

In this study, the capacitance and dielectric loss tangent of the silicone rubber which is combined with filler (30 phr~50 phr) have been measured on the range of 100 Hz~100 kHz and $30{\sim}170^{\circ}C$. It was found that when the frequency is 0.1 kHz~100 kHz and the silicone rubber is combined with 30 phr to 50 phr of filler, the capacitance of silicone rubber has increased by about 28.6 pF to 33 pF in 30 phr of filler, about 20 pF to 46.1 pF in 40 phr of filler and about 36.4 pF to 44 pF in 50 phr of filler. It seems that the volume of dielectric loss has gradually increased due to the temperature rise and the rotating of dipole in electric field through the electric dipole generated by the Si-O group which is induced by adding of filler, or the carbonyl group which is caused by oxidation. It seems that the dielectric dispersion in 0.1 kHz is caused by molecular motion of Siloxane group in main chain, and the dielectric dispersion in 10 kHz is caused by molecular motion of Methyl group in side chain.

• Advances in nano research
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• 제2권2호
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• pp.121-133
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• 2014

Polymer nanocomposites are advanced nanomaterials which exhibit dramatic improvements in various mechanical, thermal and barrier properties as compared with the neat polymer. Polystyrene/ alumina nanocomposites were prepared by an ultrasound-assisted solution casting method at filler loadings ranging from 0.2 to 2% and also at different ultrasonic frequencies, viz. 58 kHz, 192/58 kHz, 430 kHz, 470 kHz and 1 MHz. The composites were subjected to mechanical property tests (tensile and impact tests) and cavitation erosion tests to study the enhancement in functional properties. Filler dispersion in the polymer matrix was observed by SEM analysis. The effect of frequency on filler dispersion in the matrix was studied by SEM analysis and functional property enhancement of the composite material. The composites prepared at dual (high/ low) frequency (192/58 kHz) were found to show better property enhancement at low filler loadings as compared with neat polymer and also with composites prepared without ultrasound, thus reinforcing the finding that ultrasound-assisted synthesis is a promising method for the synthesis of nanocomposites.

• Elastomers and Composites
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• 제53권2호
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• pp.48-51
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• 2018

10, 20, 30, and 40% of polyvinyl chloride (PVC) were added to nitrile butadiene rubber (NBR) to modify the latter. The NBR/PVC composites containing pure NBR were synthesized to investigate properties, such as crosslinking density, hardness, tensile strength, abrasion resistance, heat resistance, solvent resistance, and filler dispersion. The experimental result revealed a decrease in crosslinking density and heat resistance with increase in the PVC content. In contrast, addition of PVC to NBR resulted in enhancement of hardness, tensile strength, solvent resistance, and filler dispersion.

• 전기학회논문지
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• 제57권9호
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• pp.1572-1578
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• 2008

The effect of the organoclay_10A nanoparticles on the DSC and Structural and Dielectrics Properties(1Hz-1MHz) for epoxy/Organoclay_10A Nanocomposites has been studied. Dielectric properties of epoxy-Organoclay nanocomposites were investigated at 1, 3, 5, 7, 9 filler concentration by weight. Epoxy nanocomposites samples were prepared with good dispersion of layered silicate using power ultrasonic method in the particles. As structural analysis, the interlayer spacing have decreased with filled nanoparticles contents increase using power ultrasonic dispersion. The maximum increase interlayered spacing was observed to decease for above 5wt% clay loading. The other hand, as decrease with concentration filler of the layered silicate were increased dispersion degree of nanoparticles in the matrix. The interesting dielectric properties for epoxy based nanocomposites systems are attributed to the large volume fraction of interfacesin the bulk of the material and the ensuring interactions between the charged nanoparticle surface and the epoxy chains.

• 한국전기전자재료학회논문지
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• 제20권4호
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• pp.348-351
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• 2007

Recently, Nanotechnology becomes a major issue in most part of industries. Nanotechnology is expected to develop various application products due to nano material mired composites is improved physical and electrical properties compared to conventional composites materials. Dielectric and insulation materials need to develop and improve like other field about nanotechnology. In this paper, we reported dielectric dispersion by size(no filler, $1.2{\mu}m$, 500 nm, 10 nm), frequencies(60, 120, 1 kHz), and temperatures($30{\sim}170^{\circ}C$). Dielectric constant of composites materials with filler shows higher than composites materials without filler and increased depending on rising temperatures in low frequency region. It was the effect that nano-filler and impurities in composites contributed to electrical conductivity. And dielectric properties depending on temperatures shows to change in low frequency region dramatically We analyzed interfacial polarization in low frequency region($10^{-2}$ Hz) and oriented polarization in high frequency region($10^{-5{\sim}6}$ Hz) on composites materials.

• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.71-73
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• 2008

The development of polymer/inorganic nanocomposites has attracted a great deal of interest due to the improved hybrid properties derived from the two different components. Various nanoscale fillers have been used to enhance polymer mechanical and thermal properties, such as toughness, stiffness, and heat resistance. The effects of the filler on the final properties of the nanocomposites are highly dependent on the filler shape, particle size, aggregate size, surface characteristics, polymer/inorganic interactions, and degree of dispersion. In this paper, we describe the influence of different $CaCO_3$ dispersion methods on the thermal properties of polyethylene terephthalate (PET)/$CaCO_3$ composites: i.e., the adsorption of $CaCO_3$ on the modified PET surface, and the hydrophobic modification of the hydrophilic $CaCO_3$ surface. We prepared PET/$CaCO_3$ nanocomposites using a twin-screw extruder, and investigated their thermal properties and morphology.

• Archives of Plastic Surgery
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• 제51권1호
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• pp.14-19
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• 2024

Background Hyaluronic acid fillers can be manufactured using various processes. They have multiple properties, including their concentration, degree of modification, and rheological data. Cohesion is one such property to evaluate gel integrity; however, there is no standardized method for calculating this parameter. This study aimed to evaluate different tests for calculating hyaluronic acid cohesion and discuss the importance of hyaluronic acid cohesion as a consideration when selecting fillers. Methods The cohesion levels of five different hyaluronic acid fillers with different rheological properties were evaluated and compared using the drop weight, compression, tack, and dispersion time tests. Results The cohesion tests yielded different results in the samples. Samples 2 and 4 showed approximately two times the number of droplets when compared with Sample 5 in drop weight test. Samples 1, 2, 3, and 4 were superior to Sample 5 in tack test. Samples 1, 2, and 3 showed cohesive appearances at 95 seconds in most cases in dispersion test. Rheological test results did not reflect the measures of cohesion. Conclusion Although there are no definite standardized tests to evaluate the cohesion of hyaluronic acid fillers, our proposed tests showed similar results for different hyaluronic acid filler products. Further studies are needed to evaluate the cohesion of hyaluronic acid fillers and determine the clinical use of this distinguishing characteristic for clinicians selecting the product of choice. Level of evidence statement: These data are Level IV evidence.

• 폴리머
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• 제26권5호
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• pp.644-652
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• 2002

전자파 차폐용 개스킷으로 적용할 수 있는 금속계 입자와 상온경화형 실리콘 수지의 페이스트계에 대한 정량적인 해석을 수행하였다. 금속입자 충전 복합재료의 전기 전도성 및 유변학적 거동은 입자의 형상, 크기, 분산상태에 많은 영향을 받는다. 고충전계에서 입자들은 매우 복잡한 응집상태를 형성하며 전단속도와 같은 외부요인에 의해 응집구조가 변하고 이에 따라 전기 전도도가 달라지게 된다. 본 연구에서는 금속입자의 평균직경 및 분산성에 따른 영향을 점도측정 및 전기 전도도 측정 방법을 통해 해석하였으며 이를 통해 금속입자의 선정기준을 제시하였다. 금속입자의 종류에 따라 점도분포, 전단응력의 영향, 전기 전도성의 변화 등이 차이를 보였다. 상대적으로 직경이 큰 입자에서 전단응력에 의한 영향이 두드러지게 나타났으며 동일 함량에서 분산성의 제어를 통해 점도 및 전기 전도도의 개선이 가능함을 보였다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1999년도 봄 학술발표회 논문집
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• pp.49-52
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• 1999