• 대한화학회지
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• 제68권2호
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• pp.74-81
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• 2024

A sulfonic acid-water-silanol system in SO₃H-functionalized MCM-41 was investigated using solid-state nuclear magnetic resonance techniques. The proton exchange rate between a water molecule and a silanol group in the S-PE-MCM-41 was determined by analyzing the 1D proton spectra, the proton EXSY spectrum, and ²H spin-lattice relaxation data under various hydration levels. Two kinds of water-bounding sites were found in the S-PE-MCM-41: weakly and strongly bound sites. Over several hours, water molecules bound to the weakly bound sites at the low hydration level migrated to the strongly bound sites. At high temperature, the S-PE-MCM-41 easily lost water molecules weakly bound to the silanol, while the strongly bound water molecules survived. Water molecules that participated in the hydration of the phenethyl sulfonate were involved in the hydrogenbonded silanol mechanism of proton conductivity. This phenomenon contributes higher proton conductivity to the S-PE-MCM-41 by the cooperation of sulfonyl and silanol groups in the proton transfer process, even at higher temperature.

• 통합자연과학논문집
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• 제3권4호
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• pp.219-225
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• 2010

On the surface of mesoporous silica thin films (MSTF) which were fabricated by sol-gel approach there are existences of water and three different silanol types including chained, germinal and isolated silanol. Their amounts changes as a function of aging time of used sol solution, as confirmed by FT-IR. The adsorbed water generates ionic carriers such as H+ and OH- and passivates the Si dangling bonds at the interface of silicon wafer-MSTF. The ionic carriers can not only transport across the thickness of thin film to enhance the leakage current but also diffuse toward the silicon wafer-MSTF interface to depassivate Si dangling bonds. On the other hand, chained silanols or germinal silanols promote the moisture adsorption of MSTF and tend to form strongly hydrogen bonded systems with adsorbed water molecules resulting in very high dielectric constant. Isolated silanol, on the contrary, affects less on electrical properties of thin film.

• The Korean Journal of Ceramics
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• 제5권3호
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• pp.265-269
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• 1999

Polyethylene was modified with silanol groups on its surface by photografting of vinyltrimethoxysilane in vapor phase by using benzophenon as a polymerization initiator and by hydrolyzing the methoxysilane groups into the silanol groups with HCI solution. The modified polyethylene formed a dense and homogeneous apatite layer on its surface in a solution with ion concentrations 1.5 times those of human blood plasma within 21 days. This kind of biomimetic process could provide techniques for fabricating apatite-polymer composites with three dimensional structure analogous to the natural bone.

• 한국세라믹학회지
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• 제30권1호
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• pp.34-40
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• 1993

ORMOSIL was synthesized with inorganic precursor, TEOS and organic precursor, PDMS, and the variation of composite properties according to the concentration of HCl, solvent content and reaction time were studied. As the concentration of HCl increased, condensation reaction was well proceeded and more regularly distributed network was observed. Increase in reactivity was found with the amount of solvent, and composite had a tendency of forming more porous microstructure as reaction time was increased, which had no influence on the bonding degree.

• 대한화학회지
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• 제19권5호
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• pp.317-324
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• 1975

$Na^+,\;Ca^{2+},\;Ni^{2+},\;Al^{3+}$ 이온이 포화된 montmorillonite상에 여러 溫度에서 일어난 $H_2O와\;D_2O$의 氣相吸着에 관하여 연구하였다. 吸着으로 인하여 생긴 OH의 IR 신축진동 band를 computer에 의하지 않고 4개의 Gauss 成分으로 나누었다. 물과 silanol OH기와의 共鳴理論은 $3625cm^{-1}와\;2680cm^{-1}$로 증명되었다. $3400cm^{-1}$와 2475cm 에서의 broad한 吸收는 吸着된 물과 水素結合을 일으키고 있는 silanol OH의 신축진동에 의한 것이었고 $3650cm^{-1}와\;2345cm^{-1}$ band는 吸着된 $H_2O와\;D_2O$에 의한 것이었다. 吸着水와 表面 OH사이의 水素結合은 精電氣的 相互作用에 의한 것임이 밝혀졌다.

• Elastomers and Composites
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• 제47권1호
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• pp.54-64
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• 2012

본 연구에서는 polar 한 silica 와 non-polar 한 고무사이의 친화력을 증대시키기 위하여 SBR 분자 주쇄에 acrylonitrile 을 도입시킨 acrylonitirle functionalized emulsion SBR 의 물성에 관하여 연구하였다. Acrylonitrile의 nitrile group 은 silica 표면의 silanol group 과 H-bond 를 형성할 수 있음으로 polar 한 silica 표면에 흡착되는 가교촉진제를 줄이고 가황반응을 촉진시키는 것으로 판단된다. SBR 및 AN-SBR 에 PEG 를 적용한 컴파운드의 경우 PEG 와 silica 표면의 silanol group 과의 상용성이 높아 가교촉진제가 polar 한 silica 표면에 흡착됨을 줄여 가교시간이 단축된 것으로 판단된다. 기계적 물성에서 AN-SBR 컴파운드는 SBR 1721 컴파운드 대비 100%, 300%에서 높은 모듈러스 값을 나타내었다. 이러한 결과는 AN-SBR 의 높은 분자량 및 nitrile group 의 도입에 따른 가교도의 상승에 의한 결과로 판단된다. 동적점탄특성 결과에서 AN-SBR 컴파운드는 SBR 1721 컴파운드 대비 $60^{\circ}C$ 에서 낮은 tan ${\delta}$ 값을 나타내었으며, 이는 nitrile group 과 silica 사이의 친화력에 따른 filler-rubber interaction의 향상에 의해 반복변형에 의한 energy dissipation 이 낮은 것으로 판단된다.

• 설비공학논문집
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• 제14권12호
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• pp.1063-1070
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• 2002

To resist ice adhesion on cooling wall is concerned to continuous ice formation in thermal storage system. In this study, ice slurries were formed with two ecological aqueous solution, one is ethanol+silanol and the other is propylene glycol+silanol. By freezing under stirring the solution of $300m\ell$ in a stainless steel vessel which was immersed and cooled in a temperature controlled bath, the shape of ice slurry and the strength of ice adhesion on wall was observed with measuring the temperature and stirring load variation. As the concentration is smaller and the supercooling degree is larger, the ice adhesion is easy to occur. When the stirring load is larger than$ 2.1\times10^{-5}W$, the ice adhesion occurred.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.521-526
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• 2007

Density functional calculations have been performed for the reactions of perfluoroalkylsilane and alkylsilane with silica surfaces. The (100) and (111) surfaces of ${\beta}-cristobalite$ are used as two possible models of the hydroxylated amorphous silica surface. This is the crystalline phase of silica with density and refractive index closest to those of amorphous silica. Moreover, two ${\beta}-cristobalite$ surfaces have the two types of silanol groups, namely the single silanols and the geminal silanols. We investigate the possible adsorption structure and formation energy of perfluoroalkylsilane and alkylsilane molecules with two type of silanol groups. The results will be compared with cluster and slab model.

• Elastomers and Composites
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• 제50권3호
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• pp.159-166
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• 2015

Silica which is used for reinforcing filler in tire industry is widely known as eco-friendly material exerting $CO_2$ reduction effect through decrease of rolling resistance and improvement of wet grip. Generally silica is classified as a highly polar filler because it contains a large number of silanol (Si-OH) group on its surface. And also silica gives a lower reinforcing effect than carbon black due to its poorer rubber-filler interaction. Therefore silica is treated with silane coupling agent or activator, then following the conventional rubber blend method, vulcanized sheets were prepared using a hot press, and cure characteristics, mechanical properties and abrasion resistance of the test specimens were investigated. It was found that with an increase in the silane coupling agent content the tensile strength, 300% modulus and abrasion resistance increased while Mooney viscosity decreased and crosslink density slightly increased with an increase of activator.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제37회 하계학술대회 초록집
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• pp.69-69
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• 2009