• 폴리머
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• 제29권2호
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• pp.156-160
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• 2005

Octamethylcyclotetrasiloxane$(D_4)$과 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane$(D_3^{Me,Ph)$을 1,1,3,3-tetramethyl-1,3-divinyldisiloxane(MVS)과 평형중합시켜 실리콘의 Si원자에 dimethyl 및 methylphenyl기가 도입된 $\alpha,\omega-vinyl$ poly(dimethyl-methylphenyl) siloxane prepolymer(VPMPS)를 제조하였으며, 또한 $D_4$와 1,3,5-trimethylcyclotrisiloxane$(D_3^:Me,H})$을 1,1,3,3-tetramethyldisiloxane(MS)와 평형중합시켜 Si원자에 dimethyl 및 methylhydrogen기가 도입된 $\alpha,\omega-hydrogen$ poly (dimethyl-methyl) siloxane prepolymer(HPDMS)를 제조하였다. Poly(acrylic acid)(PAA)을 chelating agent로 하여 nickel(II) nitrate와 iron(III) nitrate를 솔-젤 방법으로 PAA 금속염을 제조하고 이틀을 소결시켜 nickel ferrite 나노 입자를 제조하였다. 제조한 nickel ferrite는 XRD 패턴으로 확인하고 입자의 크기를 TEM으로 측정하였다 1,3-Divinyltetramethyldisilazane(VMS)으로 표면처리한 나노 실리카, nickel ferrite, VPMPS, HPDMS 및 촉매를 고속 교반기에 가하고 $130^{\circ}C$에서 컴파운딩하여 poly(organosiloxane) rubber nanocomposites를 제조하였다. Nickel ferrite 함유한 nanocomposite, POX-30과 POX-50을 각각 제조하였으며 이들의 기계적 및 열전도 특성 그리고 체적 저항을 측정하였다.

• 한국표면공학회지
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• 제56권4호
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• pp.233-242
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• 2023

In recent years, energy-management studies in buildings have proven useful for energy savings. Typically, during heating and cooling, the energy from a given building is lost through its windows. Generally, to block the entry of ultraviolet (UV) and infrared (IR) rays, thin films of deposited metals or metal oxides are used, and the blocking of UV and IR rays by these thin films depends on the materials deposited on them. Therefore, by controlling the thicknesses and densities of the thin films, improving the transmittance of visible light and the blocking of heat rays such as UV and IR may be possible. Such improvements can be realized not only by changing the two-dimensional thin films but also by altering the zero-dimensional (0-D) nanostructures deposited on the films. In this study, 0-D nanoparticles were synthesized using a sol -gel procedure. The synthesized nanoparticles were deposited as deep coatings on polymer and glass substrates. Through spectral analysis in the UV-visible (vis) region, thin-film layers of deposited zinc oxide nanoparticles blocked >95 % of UV rays. For high transmittance in the visible-light region and low transmittance in the IR and UV regions, hybrid multiple layers of silica nanoparticles, zinc oxide particles, and fluorine-doped tin oxide nanoparticles were formed on glass and polymer substrates. Spectrophotometry in the UV-vis-near-IR regions revealed that the substrates prevented heat loss well. The glass and polymer substrates achieved transmittance values of 80 % in the visible-light region, 50 % to 60 % in the IR region, and 90 % in the UV region.

• Korean Chemical Engineering Research
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• 제54권2호
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• pp.163-170
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• 2016

고분자 필름의 친수성을 향상시키기 위하여 우수한 친수성을 보이는 코팅 용액을 졸-겔법으로 합성하였다. 코팅 용액은 입자 직경이 15 nm 크기의 콜로이드 실리카에 다양한 실란커플링제인 아미노실란, 에폭시실란과 아크릴실란을 각각 반응시켜 제조하였다. 콜로이드 실리카에 아미노실란을 첨가한 코팅 용액은 바로 겔화가 진행되어 코팅 용액을 제조할 수 없었다. 반면에 에폭시실란을 첨가한 코팅 용액은 실란커플링제/콜로이드 실리카의 질량분율(R값)이 0.10~0.15에서 접촉각 $10{\sim}15^{\circ}$의 우수한 친수성을 나타내었다. 또한 아크릴실란을 첨가한 코팅 용액은 R값이 0.03~0.07에서 $5{\sim}10^{\circ}$의 접촉각을 나타내어 아미노실란과 에폭시실란을 사용했을 때 보다 우수한 친수성을 나타내었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.404-408
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• 2003

본 논문은 혐기성 공정에서 혐기성 미생물을 이용한 수소 생산에 관한 연구이다. MLSS를 고농도로 유지하기 위해서 양이온성 고분자와 실리카졸을 투입하여 혐기성 슬러지를 그래뉼로 형성 시켰다. 수소가스 생산은 메탄생성 박테리아가 저해로 발생량이 많지 않았다. 낮은 pH(<5.5)에도 불구하고 메탄생성 미생물의 활성은 막지 못했는데 수소 가스의 발생은 메탄가스의 증가와 연관이 되어 있다고 판단된다. pH 제어를 제외한 다른 방법이 도입된다면 효과적인 수소 발생을 할수 있으리라 기대된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.339-342
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• 2003

본 논문은 혐기성 공정에서 혐기성 미생물을 이용한 수소 생산에 관한 연구이다. MLSS를 고농도로 유지하기 위해서 양이온성 고분자와 실리카졸을 투입하여 혐기성 슬러지를 그래뉼로 형성 시켰다. 수소가스 생산은 메탄생성 박테리아가 저해로 발생량이 많지 않았다. 낮은 pH(<5.5)에도 불구하고 메탄생성 미생물의 활성은 막지 못했는데 수소 가스의 발생은 메탄가스의 증가와 연관이 되어 있다고 판단된다. pH 제어를 제외한 다른 방법이 도입된다면 효과적인 수소 발생을 할 수 있으리라 기대된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.306-308
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• 2007

Poly(ethylene glycol) dimethyl ether (PEGDME)/fumed silica/ 1-methyl -3-propylimidazolium iodide (MPII)/$I_2$ mixtures were used as polymer electrolytes in solid state dye-sensitized solar cells (DSSCs). The contents of MPII were changed and the concentration of $I_2$ was fixed at 0.1 mole% with respect to the MPII. The maximum ionic conductivity was obtained at [EG]:[MPII]:[$I_2$]=10:1.5:0.15. It was supposed that the maximum of ionic conductivities would match with that of cell efficiencies, if the ionic conductivity is a rate determining step in the sol id state DSSCs. However, the maximum composition did not show the maximum solar cell performance, indicating the mismatch between ionic conductivity and cell performance. This suggests that the ionic conductivity may not be the rate controlling step in determining the cell efficiency in these experimental conditions, whereas other parameters such as the electron recombination might play an important role. Thus, we tried to modify the surface of the $TiO_2$ particles by coating a thin metal oxide such as $Al_2O_3$ or $Nb_2O_5$ layer to prevent electron recombination. As a result, the maximum of the cell efficiency was shifted to that of the ionic conductivity. The peak shifts were also attempted to be explained by the diffusion coefficient and the lifetime of electrons in the $TiO_2$ layer.

• Corrosion Science and Technology
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• 제14권5호
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• pp.213-217
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• 2015

Recently, household electronic industries require environmentally-friendly and highly functional steels in order to enhance the quality of human life. Customers especially require both excellent corrosion and abrasion resistant anti-fingerprint steels for digital TV panels. Thus POSCO has developed new functional electro-galvanized steels, which have double coated layers with organic-inorganic composites on the zinc surface of the steel for usage as the bottom chassis panel of TVs. The inorganic solution for the bottom layer consists of inorganic phosphate, magnesium, and zirconium compounds with a small amount of epoxy binder, and affords both improved adhesion properties by chemical conversion reactions and corrosion resistance due to a self-healing effect. The composite solution for the top layer was prepared by fine dispersion of organic-inorganic ingredients that consist of a urethane modified polyacrylate polymer, hardener, silica sol and a titanium complex inhibitor in aqueous media. Both composite solutions were coated on the steel surface by using a roll coater and then cured through an induction furnace in the electro-galvanizing line. New anti-fingerprint steel was evaluated for quality performance through such procedures as the salt spray test for corrosion resistance, tribological test for abrasion resistance, and conductivity test for surface electric conductance regarding to both types of polymer resin and coating weight of composite solution. New composite coated anti-fingerprint steels afford both better corrosion resistance and abrasion properties compared to conventional anti-fingerprint steel that mainly consists of acrylate polymers. Detailed discussions of both composite solutions and experimental results suggest that urethane modifications of acrylate polymers of composite solutions play a key role in enhanced quality performances.

• Macromolecular Research
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• 제15권3호
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• pp.221-224
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• 2007

A silica-magnesium bisupport (SMB) was prepared by a sol-gel method for use as a support for a metal-locene/Ziegler-Natta hybrid catalyst. The prepared $rac-Et(Ind)_2ZrCl_2/TiCl_4$/MAO(methylaluminoxane)/SMB catalyst was applied to the copolymerization of ethylene with l-hexene using a variable triethylaluminum (TEA)/transition-metal (Ti) ratio and fixed MAO/transition-metal (Zr) ratio. The effect of the Al(TEA)/Ti ratio on the physical properties and chemical composition distributions (CCDs) of the ethylene-hexene copolymers produced by the hybrid catalyst was investigated. In the ethylene-hexene copolymers, two melting temperatures attributed to the metal-locene and Ziegler-Natta catalysts were clearly observed. The number of CCD peaks was increased from six to seven and the temperature region in which the peaks for the short chain branches of the ethylene-hexene copolymer were distributed became lower as the Al(TEA)/Ti ratio was increased from 300 to 400. Furthermore, the temperature regions corresponding to the lamellas in the copolymer became lower and those corresponding to the small lamellas in the copolymer became higher as the Al(TEA)/Ti ratio was increased from 300 to 400. In the copolymer produced with Al(TEA)/Ti = 500, however, only four CCD peaks were observed and the short chain branches were poorly distributed.

• 통합자연과학논문집
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• 제2권1호
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• pp.18-23
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• 2009

This minireview provides the chosen examples of our recent discoveries in the polymerization of hydrosilanes, dihydrosilole, lactones, and vinyl derivatives using various catalysts. Hydrosilanes and lactones copolymerize to give poly(lactone-co-silane)s with $Cp_2MCl_2$/Red-Al (M = Ti, Zr, Hf) catalyst. Hydrosilanes (including dihydrosilole) reduce noble metal complexes (e.g., $AgNO_3$, $Ag_2SO_4$, $HAuCl_4$, $H_2PtCl_6$) to give nanoparticles along with silicon polymers such as polysilanes, polysilole, polysiloxanes (and silicas) depending on the reaction conditions. Interestingly, phenylsilane dehydrocoupled to polyphenylsilane in the inert nitrogen atmosphere while phenylsilane dehydrocoupled to silica in the ambient air atmosphere. $Cp_2M/CX_4$ (M = Fe, Co, Ni; X = Cl, Br, I) combination initiate the polymerization of vinyl monomers. In the photopolymerization of vinyl monomers using $Cp_2M/CCl_4$ (M = Fe, Co, Ni), the photopolymerization of MMA initiated by $Cp_2M/CCl_4$ (M = Fe, Co, Ni) shows while the polymerization yield decreases in the order $Cp_2Fe$ > $Cp_2Ni$ > $Cp_2Co$, the molecular weight decreases in the order $Cp_2Co$ > $Cp_2Ni$ > $Cp_2Fe$. For the photohomopolymerization and photocopolymerization of MA and AA, the similar trends were observed. The photopolymerizations are not living. Many exciting possibilities remain to be examined and some of them are demonstrated in the body of the minireview.

• 접착 및 계면
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• 제2권2호
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• pp.20-27
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• 2001

투명 플라스틱 중에서 가장 많이 이용되고 있는 재료의 하나로 폴리카보네이트 수지가 알려져 있다. 이 수지는 투명 플라스틱 중에서도 굴절률이 1.584로 유리의 굴절률에 상응하는 수치를 가지고 있어 렌즈, 창소재 등 광학적 용도에 있어서 유리의 대체품으로서 호응이 크다. 그러나 장점에 반하여 표면 경도가 낮기 때문에 마찰에 의해 긁히기 쉽고 용제 등에 대한 내성도 나쁜 편이다. 특히 옥외 창 재료로 사용할 경우에는 자외선의 흡수에 따른 표면의 황변이 심각한 문제가 되어 사용상에 한계를 가지고 있다. 본 연구에서는 실리콘 하드 코팅제의 우수한 내마모성 및 광학 특성을 가지며 또한, 무기 실록산 네트워크에 자외선 흡수 능력을 가진 유기 실란을 도입시켜 폴리카보네이트 수지의 취약한 표면을 효율적으로 보호하면서 내후성 또한 뛰어난 표면 보호 코팅제를 제공하기 위하여 quinine과 3-isocyanato propyl triethoxy silane(3-IPTES) 으로부터 N-triethoxy silyl propyl quinine urethane (TESPQU)을 합성하였다. 이 물질을 methyl triethoxy silane(MTES) 과 공가수분해 후 축합시켜 실록산 네트워크 속으로 도입시켰다. 또한 benzophenone 계통의 자외선 흡수제를 유가실란 축합물에 단순 배합한 경우와 비교하였다. 주사슬에 UV에 안정한 형태의 유가 실란, TESPQU를 도입한 경우 좋은 내후성을 나타냄을 확인할 수 있었다.