• Elastomers and Composites
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• 제41권3호
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• pp.157-163
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• 2006

침전실리카와 친수성 및 소수성 흄실리카를 사용하여 첨가량에 따른 실리콘 고무인상재의 젖음성과 기계적 물성 향상 연구를 수행하였다. 고무인상재의 경화시간에는 흄실리카 종류보다는 입자크기가 영향을 미쳤으며, 입자크기가 가장 작은 A300을 사용할 경우 약 9분 정도의 경화시간 지연을 초래하였다. 소수성 흄실리카인 R972를 대체 사용할 경우 고무인상재의 젖음성 특성이 가장 우수하였다. 침전실리카와 A300 흄실리카를 85:15로 혼합하여 사용할 경우 인열강도가 약 1.5N/mm 정도 증가하지만 경화시간의 과도한 지연과 더불어 점도가 상승하기 때문에, 흐름성 및 기계적물성 측면에서 침전실리카와 흄실리가(A300)를 90:10으로 혼합하여 사용하는 것이 최적이었다.

• 고무기술
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• 제7권1호
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• pp.17-22
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• 2006

• Elastomers and Composites
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• 제38권2호
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• pp.175-179
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• 2003

For the total description of mechanical behaviors of elastomers, it is necessary to know the so-called rheological constitutive equation i.e. the strain-energy density function (W) in case of elastomers, which necessitates biaxial tensile results of elastic body. This paper first describes the experimental results of biaxial tensile measurements on poly(siloxane) model networks. W was estimated from its differential form i.e. the $1^{st}$ differential of W is stress. The W was found to reproduce the experimental stress-strain results, and the W estimated for silica filled poly(siloxane) networks suggest a different behavior between conventional precipitated silica and in situ formed silica. The difference suggests the different surface property of the two silicas.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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• pp.107-116
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• 2005

Precipitated silicas modified by aluminium were characterised using inverse liquid chromatography in anhydrous heptane with squalene as probes. Their monolayer capacities of adsorption, Langmuir's and Henry's constants were determined from the desorption isotherms according to frontal analysis. A narrow band consisting of isotherms was observed. The introduction of aluminium has little influence on the monolayer capacity, Langmuir's constants and the Henry constant. Experimental data show that neither the amounts of aluminium on the silica nor the methods of the introduction of aluminium into the silica influence the interactions between the squalene and the silicas.

• 펄프종이기술
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• 제37권2호
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• pp.38-46
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• 2005

Experimental work was carried out in order to produce a novel grade of ink-jet paper that has both high print-out quality and price competitiveness. Usually, silica and PVOH has been used for ink-jet paper to design the coating layer that has a hydrophilic and micro-porous structure. However, poor rheological characteristics and low productivity of the silica-PVOH system make the price of the ink-jet paper high. The main focus of this study was replacing the conventional silica (coating pigment) PVOH (binder) coating system with the new PCC (coating pigment) cationic starch (binder) coating system, and optimizing thecoating technology associated with PPC-cationic starch system. In this study, ink-jet print quality of PCC-coated papers was compared with that of silica-coated paper. Two types of PCC were used: conventional type and colloid type. It turned out that PCC C, a conventional coating pigment, has not given a desirable result: it showed high dot reproduction, but it gave low optical density. In spite of low dot reproduction, the qualities of PCC A were comparable or superior to those of silica in optical density, color reproduction, and the uniformity of printing surface. It was also shown that the problems that are happened when the dosage level of cationic starch was too low were varied with ink-type used in each printer. However, in the case of low binder level, the produced image was widely spread resulting fromtoo low optical density of images, or from the lack of bonding ability to set ink into coating surface.

• 폴리머
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• 제35권4호
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• pp.342-349
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• 2011

실리카의 표면 개질제인 vinyltriethoxysilane(VTEOS)의 함량에 따른 실리카로 보강된 실리콘 고무의 기계적 물성 변화 및 내열성, 내유성, 압축 영구줄음률, 반발탄성 및 가교밀도 변화를 연구하였다. 결과로 VTEOS의 함량이 2.0 phr까지 증가함에 따라 경도는 상승하였으나 인장강도 파단신율, 인열강도가 감소하였다. 내열시험에서는 VTEOS의 함량이 증가될수록 경도변화, 인장강도 변화율, 파단신율 변화율이 크게 감소하였다. VTEOS 2.0 phr에서 가장 우수한 내열특성을 나타내었다. 또한 VTEOS의 함량이 증가될수록 실리콘 고무의 내유성이 증진되었으며, VTEOS 미첨가 시보다 경도 하락폭이 크게 낮았으며, 파란신율 변화율은 약 2배 이상 감소하였다. 반발탄성도 VTEOS의 함량이 증가될수록 우수하였으며, 압축 영구줄음률 역시 VTEOS가 증가될수록 감소하였다. 가교실험 결과 VTEOS가 증가될수록 최대 토크값와 가교밀도가 크게 향상되었다.

• Elastomers and Composites
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• 제39권4호
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• pp.263-273
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• 2004

The effects of zinc surfactant (ZB) on the bis(triethoxysilylpropyl)disulfide (TESPD)-silica mixture in natural rubber (NR) and solution butadiene-co-styrene rubber(S-SBR) were compared with respect to their rheological property, processability, physical properties, and silica dispersion. In the NR compound, addition of the ZB increased the reversion resistance time (T-2), the tensile modulus, and the BO time; however, lowered the viscosity, the HBU, and tans values. In the S-SBR copound, addition of the ZB increased the $tan{\delta}$ values while lowered the T-2, the tensile modulus the BO time, the viscosity, and the HBU of the compound. In the NR compounds, addition of the ZB significantly increased the processability and mechanical property. However, in the S-SBR compounds, it improved the processability the mechanical property was not improved.

• 한국세라믹학회지
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• 제34권9호
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• pp.941-948
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• 1997

CuCl nanocrystallites dispersed nonlinear optical silica and borosilicate glasses were fabricated by sol-gel process. CuCl powder was dissolved in TEOS(Si(OC2H5)4) and TMB((CH3O)3B), precursors of silica and borosilicate glasses, with ethanol, water and HCl, and precipitated through the heat treatment in the matrix glass. The optical properties of CuCl doped glasses were measured using the spectrophotometer at room temperature and low temperature(77K); Z1, 2 and Z3 exciton peaks from the absorption spectra, were observed at about 370 nm and 380 nm, respectively. The average radius of nanocrystallites, calculated from the blue shift of Z3 excitons, was measured according to annealing temperature and time. The precipitation temperature of CuCl nanocrystallites was decreased when boron was added to silica glass. Increase of annealing temperature and time made average radius of nanocrystallites saturated about 2 nm.

• Elastomers and Composites
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• 제37권2호
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• pp.115-123
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• 2002

고압애자용 실리콘 고무를 제조하기 위해 사용되는 polydimethylsiloxane(PDMS)의 vinyl기 함량과 실리카의 종류가 전기특성 및 물성에 미치는 영향을 연구하였다. 실리콘 폴리머의 비닐함량이 증가함에 따라 가교밀도와 경도가 높아졌으며 이로 인해 인장강도, 체적저항 및 트래킹 특성이 증가하였다. 건식실리카로 보강된 실리콘 고무가 습식실리카로 보강된 실리콘 고무보다 전기적 특성 및 물성이 우수하였으며 이는 실리카에 존재하는 수분의 함량에 영향을 받는 것을 알 수 있었다.

• 한국분말재료학회지
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• 제12권2호
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• pp.122-130
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• 2005

Layered silicate was synthesized at hydrothermal condition from silica adding to various materials. Nano-clay was synthesized by intercaltion of various amine compounds into synthetic layered silicate. The products were analysed by XRD, SEM, and FT-IR in order to examine the condition of synthesis and intercalation. From the results, it was confirmed that kaolinite was synthesized from precipitated silica and gibbsite at $220^{\circ}C$ during 10 days, and hetorite was synthesized from silica sol at $100^{\circ}C$ during 48 h. Na-Magadiite was synthesized from silica gel at $150^{\circ}C$ during 72 h, and Na-kenyaite was synthesized from silica gel at $160^{\circ}C$ during 84 h. Nano-clay was prepared using synthetic layered silicate intercalated with various amine compounds. Kenyaite was easily intercalated by various organic compounds, and has the highest basal-spacing value among other layered silicates. Basal-spacing was changed according to the length of alkyl chain of amine comopounds. Polymer can be easily intercalated by dispersion with large space of interlayer. Finally, epoxy/nano-clay nanocomposite can be easily prepared.