• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.287-288
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• 2008

에폭시-층상실리케이트 나노콤포지트의 균질분산과 층상실리케이트내로 침투되는 박리정도를 향상시키기 위해 친환경적 분산기법인 물리적방법으로 Homogenizer와 Power Ultrasonic를 적용한 기법을 실시하였다. Homogenizer의 최적속도를 얻기 위해 분산시킨 나노콤포지트의 박리정도, 유리천이온도를 구할 수 있었고, Homogenizer와 Ultrasonic을 동시에 적용하여 최적시간을 구하기 위해 적용된 나노콤포지트를 절연파괴 강도의 Weibull Plots을 통하여 판단할 수 있는 좋은 결과를 얻을 수 있었다.

• Journal of the Korean Applied Science and Technology
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• v.24 no.3
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• pp.264-271
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• 2007

Effect of dispersion methods for Vapor Grown Carbon Fibers (VGCF) in epoxy caused the change in mechanical properties of VGCF/epoxy nanocomposites, such as tensile modulus and tensile strength. The influence of VGCF types - atmospheric plasma treated (APT) VGCF and raw VGCF - and their contents was discussed in detail. Treating VGCF with atmospheric plasma enhanced the surface energy, therefore improved the bonding strength with epoxy matrix. Two different methods used to disperse VGCF were ultrasonic and mechanical homogenizer methods. When using dispersion solutions, the VGCF demonstrated good dispersion in ethanol in both homogenizer and ultrasonic method. The uniform dispersion of VGCF was investigated by scanning electron microscopy (SEM) which showed well-dispersion of VGCF in epoxy matrix. The tensile modulus of raw VGCF/epoxy nanocomposites obtained by ultrasonic method was higher than that of one obtained by homogenizer method. APT VGCF/epoxy nanocomposites showed higher tensile strength than that of raw VGCF/epoxy nanocomposites.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.29-32
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• 2003

Multi -walled carbon nanotube(MWNT)/poly(methyl methacrylate) composites were fabricate d through film casting. Manufacturing process was established using a ultrasonic cleaner and a homogenizer. Acetone was used as a solvent to melt PMMA and mix with MWNT. The ultrasonic cleaner performed an important role in producing MWNT/MMA nanocomposites. Ultrasonic energy was utilized to disperse MWNT in acetone. Also, melting PMMA in acetone and mixing MWNT and PMMA were achieved using the homogenizer. It was confirmed that the nanohlbes were well dispersed in PMMA according to SEM images.

• The Journal of the Acoustical Society of Korea
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• v.41 no.1
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• pp.9-15
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• 2022

In order to overcome the limitation of conventional nanoparticle dispersion methods such as sonicator or homogenizer, a filtration method using an ultrasonic atomization effect and cyclones was proposed in this study. A 0.5 wt% suspension was made with Al₂O₃ powder with an average diameter of 250 nm. The suspension was filtered by the proposed method after pre-dispersing using a sonicator and a homogenizer, respectively. As the result, in the case of the suspension after pre-dispersing with a sonicator, the particle size distribution of the filtered suspension started showing up a single normal distribution indicating the mode of the average diameter only after the 3rd cyclone process. On the other hand, in the case of the suspension with the homogenizer pre-dispersion, similar results appeared from the 2nd cyclone process. Filtration of various types of nanoparticles is expected to be possible by adjusting ultrasonic atomization frequency and manipulating the design of the cyclone.

• Applied Chemistry for Engineering
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• v.1 no.2
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• pp.224-231
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• 1990

To improve the dispersion of platinum catalyst, the effects of carbon black surface treatment, solvents, surfactants, and ultrasonic homogenizing were examined. Upon introducing the hydrophilic groups acting as an anchorage center of the catalyst on the surface of carbon black by oxidation, the migrating and growing of platinum particles(or ions) during reduction could be restricted. When mixed solvents, surfactants, or ultrasonic homogenizer were used to disperse catalysts on the carbon black, the dispersion of catalyst could be improved, due to the good permeation of chloroplatinic acid through the pore of carbon black. Among the impregnation methods, the method using ultrasonic homogenizer with mixed solvent was the most excellent. Using this method the particle sized could be minimized in less than $30A^{\circ}$ and distributed homogeneously.

• Korean Journal of Materials Research
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• v.19 no.3
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• pp.156-162
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• 2009

Lubricant-based nanofluids were prepared by dispersing carbon nanoparticles in gear oil. In this study, the effects of the particle size, shape and dispersity of the particles on the tribological properties of nanofluids were investigated. Dispersion experiments were conducted with a high-speed bead mill and an ultrasonic homogenizer, and the surfaces of the nanoparticles were simultaneously modified with several dispersants. The effective thermal conductivity of the nanofluids was measured by the transient hot-wire method, and the tribological behaviors of the nanofluids were also investigated with a disk-on-disk tribo-tester. The results of this study clearly showed that the combination of the nanoparticles, the deagglomeration process, the dispersant and the dispersion solvent is very important for the dispersity and tribological properties of nanofluids. Lubricant-based nanofluids showed relatively low thermal conductivity enhancement, but they were highly effective in decreasing the frictional heat that was generated. For nanofluids containing 0.1vol.% graphite particles in an oil lubricant, The friction coefficient in the boundary and fluid lubrication range was reduced to approximately 70% of the original value of pure lubricant.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.361-362
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• 2008

에폭시 메트릭스에 $10{\pm}5nm$ SiO2 입자를 함량별 (1,3,5,7,9wt%)로 혼합하여 초음파 및 균질기를 이용한 분산을 실시하여 나노콤포지트를 제조하였다. 엉킴이 있는 나노입자를 물리적분산법을 이용하여 분산시킬 수 있었고, 그 결과 여러특성을 연구하였다. 기계적 굴곡강도 특성은 나노입자 충진함량 증가에따라 증가되는 경향을 나타내었고, 무충진 에폭시수지에 비하여 상대적으로 높은 굴곡강도를 나타내었다. 나노입자의 충진함량 증가에따라 절연파괴강도는 1wt%에서 가장 높는 절연파괴강도를 기록하였고 함량증가에 따라 약간 감소되는 경향을 보이고 있다. 이는 여러 연구자의 경향과 대체로 유사함을 알 수 있었다.

• Korean Journal of Materials Research
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• v.17 no.9
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• pp.493-499
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• 2007

Oil-based nanofluids were prepared by dispersing nonconducting fibrous $Al_2O_3$ and spherical AlN nanoparticles in transformer oil. In this study, the effects of wet grinding and surface modification of particles on thermal and electrical properties of nanofluids were investigated. Grinding experiments were conducted with high-speed bead mill and ultrasonic homogenizer and nanoparticles were surface modified by oleic acid and polyoxyethylene alkyl acid ester(PAAE) in n-hexane or transformer oil, at the same time. It is obvious that the combination of nanoparticle, dispersant and dispersion solvent is very important for the dispersity of nanofluids. For nanofluids containing 1.0vol.% AlN particles in transformer oil, the enhancement of thermal conductivity was 11.6% compared with pure transformer oil. However, the electric-insulating property of AlN nanofluids was very low due to used dispersant itself. Therefore, the effect of the dispersant on thermal/electrical/physical properties of the transformer oil should be considered before selecting a proper dispersant.