• 전기화학회지
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• 제11권3호
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• pp.190-196
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• 2008

The multilayered membrane for lithium rechargeable batteries based on poly (vinylidene fluoride) (PVdF) is prepared with the coated layer containing nano-sized filler. The prepared membranes were subjected to studies of mechanical strength, morphology, interfacial stability, impedance spectroscopy, ionic conductivity, and cycle performance. The localized inorganic filler in the PVdF composite membrane rendered mechanical strength much reduced because of its low stretching ratio and it results in around half value of the mechanical strength of highly stretched PVdF membrane. In order to achieve high ionic conductivity and interfacial stability without sacrificing high mechanical strength, coating layer with nano-filler was newly introduced to PVdF membrane. The ionic conductivity of the coated membrane was 1.03 mS/cm, and the interface between the coating layer and PVdF membrane was stable when the membrane was immersed into liquid electrolyte. The discharge capacity of the cell based on nano-filler coated PVdF membrane was around 91% of the initial discharge capacity after 250 cycles, which is an improvement in cycle performance compared to the case for the non-coated PVdF membrane.

• Elastomers and Composites
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• 제55권4호
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• pp.306-313
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• 2020

To investigate the reinforcing effects of functional fillers in nitrile rubber (NBR) materials, high-structure carbon black (HS45), coated calcium carbonate (C-CaCO3), silica (200MP), and multi-walled carbon nanotubes (MWCNTs) were used as functional filler, and carbon black (SRF) as a common filler were used for oil-resistant rubber. The curing and mechanical properties of HS45-, 200MP-, and MWCNT-filled NBR compounds were improved compared to those of the SRF-filled NBR compound. The reinforcing effect also increased with a decrease in the particle size of the fillers. The C-CaCO3-filled NBR compound exhibited no reinforcing effect with increasing filler concentration because of their large primary particle size (2 ㎛). The reinforcing behavior based on 100% modulus of the functional filler based NBR compounds was compared by using several predictive equation models. The reinforcing behavior of the C-CaCO3-filled NBR compound was in accordance with the Smallwood-Einstein equation whereas the 200MP- and MWCNT-filled NBR compounds fitted well with the modified Guth-Gold (m-Guth-Gold) equation. The SRF- and HS45-filled NBR compounds exhibited reinforcing behavior in accordance with the Guth-Gold and m-Guth-Gold equations, respectively, at a low filler content. However, the values of reinforcement parameter (100Mf/100Mu) of the SRF- and HS45-filled NBR compounds were higher than those determined by the predictive equation model at a high filler content. Because the chains of SRF composed of spherical filler particles are similarly changed to rod-like filler particles embedded in a rubber matrix and the reinforcement parameter rapidly increased with a high content of HS45, the higher-structured filler. The reinforcing effectiveness of the functional fillers was numerically evaluated on the basis of the effectiveness index (��SRF/��f) determined by the ratio of the volume fraction of the functional filler (��f) to that of the SRF filler (��SRF) at three unit of reinforcing parameter (100Mf/100Mu). On the basis of their effectiveness index, MWCNT-, 200MP-, and HS45-filled compounds showed higher reinforcing effectiveness of 420%, 70%, and 20% than that of SRF-filled compound, respectively whereas C-CaCO3-filled compound exhibited lower reinforcing effectiveness of -50% than that of SRF-filled compound.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2070-2076
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• 2015

Nano composite materials were multi-constituent combinations of nano dimensional phases with distinct differences in structure, chemistry and properties. Nano particles were less likely to create large stress concentrations and thereby can avoid the compromise of the material ductility while improve other mechanical properties. Corona discharge was an electrical discharge. The ionization of a fluid surrounding a conductor was electrically energized. This discharge would occur when the strength of the electric field around the conductor was high enough to form a conductive region, but not high enough to cause electrical breakdown or arcing to nearby objects. This paper shows all the studies done on the preparation of nano fillers. Special attention has given to the ACSR transmission line conductor, TiO₂ nano fillers and also to the evaluation of corona resistance on dielectric materials discussed in detail. The measurement of the dielectric properties of the nano fillers and the parameters influencing them were also discussed in the paper. Corona discharge test reveals that in 0%N ACSR sample corona loss was directly proportional to the applied line voltage. No significant change in corona loss between 0%N and 1%N. When TiO₂ nano filler concentration was increased up to 10%N fine decrement in corona loss was found when compared to base ACSR conductor, corona loss was decreased by 40.67% in 10%N ACSR sample. It was also found from the surface conditions test that inorganic TiO₂ nano filler increases the key parameters like tensile strength and erosion depth.

• 반도체디스플레이기술학회지
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• 제12권1호
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• pp.23-28
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• 2013

Epoxy resins are widely used in microelectronics packaging such as printed circuit board and encapsulating for semiconductor manufacturing. Water can diffuse into and through the epoxy matrix systems and moisture absorption at boarding interfaces of matrix resin systems can lead to a hydrolysis at the interfaces resulting in delamination of encapsulating materials. In the study, the changes of diffusion coefficient and moisture content ratio of epoxy resin systems with nano-sized fillers according to the change of liquid type epoxy resins were investigated. RE-304S, RE-310S, RE-810NM and HP-4032D as a epoxy resin, Kayahard AA as a hardener, and 1B2MI as a catalyst were used in these epoxy resin systems. After curing, moisture content ratios were measured with time under the 85 and 85% relative humidity condition using a thermo-hydrostat. The maximum moisture absorption ratio and diffusion coefficient of EMC decrease with the filler content. It can be seen that these decreases are due to the increase of filler surface area and the decrease of moisture through channel with the content of nano-sized filler.

• 폴리머
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• 제30권2호
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• pp.129-134
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• 2006

[ $Na^+-Montmorillonite(MMT)$ ], 실리카, 탄산칼슘 및 MMT를 표면 개질한 무기 나노입자를 이용한 나노복합재료를 제조하고 이들의 열적 특성을 고찰하였다. 나노복합재료의 연속상 폴리우레탄의 분자량은 $20000{\sim}28000$이고 충전비에 큰 영향이 없었으며, 이들의 분자량 분포는 $1.5{\sim}2.0$로 비교적 일정하였다. 나노복합재료의 층간거리(d-spacing)는 순수한 충전제의 층간거리보다 모두 증가되었다. 한편 초기 열분해 온도는 폴리우레탄 매트릭스보다 모두 높게 나타났으며, 나노복합재료의 초기 열분해 온도는 $250{\sim}280^{\circ}C$ 이었다. 또한 열중량 감소 폭도 나노복합재료의 경우가 낮았으며, 완전 열분해 온도는 약 $50^{\circ}C$ 높게 나타났다. 인장강도는 탄산칼슘 충전 복합재료가 가장 높았으며, 신율은 MMT 충전 나노 복합재료가 247%로 가장 크게 나타났다. 또한 충전제의 함량이 증가할수록 인장강도는 증가하였으며 실리카 충전 복합 재료의 인장강도가 가장 낮게 나타났고, 탄산칼슘 충전 복합재료의 인장강도가 가장 높게 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.99-99
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• 2010

Polymer nanocomposite has been attracting much attention as a new insulation material, since homogeneous dispersion of nm-sized inorganic fillers can improve various properties significantly. In this paper, various kinds of epoxy based nanocomposites were made and AC breakdown strength of Nano-TiO2 and micro-silica filler mixture of epoxy based composites were studied by sphere to sphere electrode. Moreover, nano- and micro-filler combinations were adopted as an approach toward practical application of nanocomposite insulation materials. Nano-TiO2 particle size is about 10nm and composites ratio was resin (100) : hardener (82) : accelerator (1.5). AC breakdown test was performed at room temperature (25 [$^{\circ}C$], 80 [$^{\circ}C$] and 100 [$^{\circ}C$] in the vicinity of Tg (90[$^{\circ}C$]). And thermal conductivity were measured by ASTM-D5470.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.160-163
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• 2011

Polymer nanocomposite has been attracting more attention as a new insulation material because homogeneous dispersion of nano-sized inorganic fillers can improve various properties significantly. In this paper, various kinds of epoxy-based nanocomposites were made, and the AC breakdown strengths of Nano filler and micro-$SiO_2$ filler mixtures of epoxy-based composites were analyzed using sphere-to-sphere electrodes. Moreover, nano- and microfiller combinations were investigated as an approach to practical application of nanocomposite insulation materials. Its composition ratio was 100 (resin):82 (hardener):1.5 (accelerator). AC breakdown tests were performed at room temperature ($25^{\circ}C$), $80^{\circ}C$, and $100^{\circ}C$ in the vicinity of $T_g$ ($90^{\circ}C$). Thermal conductivity was measured using TC-30.

• 폴리머
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• 제31권5호
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• pp.379-384
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• 2007

본 연구는 열안정성을 향상시킨 무기나노 분말충전 나노복합재료를 우레탄 중합방법으로 제조하였다. 나노복합재료의 구조와 표면 특성은 XRD와 FT-IR을 통하여 알아보았고, 열안정성은 TGA와 DSC를 통하여 알아보았으며, SEM을 이용하여 복합재료의 모폴로지를 관찰하였다. 복합재료의 기계적 물성은 UTM을 사용하여 측정하였다. 실험 결과, MMT를 충전한 나노복합재료의 층간거리가 $7.5{\AA}$ 증가하였고, Silica 내 Si-O기에 의해 $1038cm^{-1}$에서 새로운 피크가 나타났다. 또한 열안정성과 기계적 물성도 폴리우레탄 매트릭스보다 향상된 것을 확인할 수 있었다.

• 펄프종이기술
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• 제46권4호
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• pp.1-10
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• 2014

In papermaking industry, inorganic fillers are widely used for the purpose of improving opacity, brightness, printability, uniformity and dimensional stability. They are also useful for production costs and energy savings. In the past, inorganic fillers in papermaking industry only focused on micro-scale but recently, new trials on nano-powdered technology are applying. Even nano-powdered fillers are rapidly utilized for improving the optical and surface properties in coating and surface sizing, there still have some problems in wet-end process due to poor dispersibility and retention. In this study, nano-particled calcium carbonate was produced by milling the PCC and its applicability between micro sized and nano sized calcium carbonated was compared in wet-end process, and finally the sheet properties were evaluated. Nano-PCC was not retained in sheet structure without applying retention system, but with retention system nano-powdered PCC was absorbed on fiber surface with expanding the fiber networks. The application of PAM-bentonite system has resulted in high ash retention and bulky structure for copier paper, and good optical properties in brightness and opacity. However, it required to solve the weakness of low tensile property due to interruption of hydrogen bonding by nano fillers.

• 폴리머
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• 제31권5호
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• pp.404-409
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• 2007

본 연구에서는 무기계 나노 분말을 충전하여 난연성이 우수한 폴리우레탄 나노복합재료를 우레탄 반응에 의해 제조하였다. 또한 나노복합재료의 난연특성을 콘 칼로리미터 분석과 한계산소지수 시험으로 확인하였다. MMT-PU와 $Bi_2O_3-PU$ 나노복합재료의 최대 열 방출속도는 모두 폴리우레탄 매트릭스보다 50% 감소하였으며, $MMT/Bi_2O_3-PU$ 복합재료의 난연 특성이 가장 우수하였다. 또한 한계산소지수도 충전제의 함량에 따라 감소하는 경향을 보였으며, 모두 20 이상이었다. 복합재료의 최대 열 방출속도는 폴리우레탄 매트릭스보다 모두 지연되었으며 최대 열 방출속도는 $Bi_2O_3-PU$, MMT-PU, $MMT/Bi_2O_3-PU$ 순으로 각각 764, 707, $635kW/m^2$ 이었으며, $MMT/Bi_2O_3-PU$ 복합재료의 난연성이 가장 우수하였다. 한편 폴리우레탄 나노복합재료의 연소시 충전제가 충전됨에 따라 $CO_2$ 생성량은 감소하였고 CO 생성량은 증가하였으며 이로부터 본 연구에서 제조한 복합재료의 난연성이 향상된 것을 확인하였다.