Preparation and hydrophobicity property of polymer nanocomoposites with organo-silanized modified silica

김석조,강주희,권세진,석웅철,임종태,송호준,이상국 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

Silica nanoparticle is a promising candidate for hydrophobic film such as mobile display, electronic device etc. however silica has hydroxyl group that means limited hydrophobicity. In this case, we enhanced hydrophobicity property by using fluoro silane, long-chain alkyl silane, epoxy silane. Hydrophobic film is made of polymer and organo-silanized modified silica. In summary, hydrophobic property is best that fluorinated silica is superior to other organo-silanized modified silica.

실란/실록산계 에멀전 발수제를 혼입한 시멘트 페이스트의 발수특성

강석표 ( Kang Suk-pyo ),홍성욱 ( Hong Seong-uk ),강혜주 ( Kang Hye-ju ),양승현 ( Yang Seung Hyeon ) 한국건축시공학회 2021 한국건축시공학회지 Vol.21 No.1

본 논문은 시멘트계 재료의 표면 및 구체에 소수성을 부여하여 내구성을 향상시키기 위한 기초연구이다. 실란/실록산계 혼합형 발수제를 혼입한 시멘트 페이스트를 제조하고 초기 수화성능 및 유동성능, 재령별 압축강도를 측정하였다. 또한 표면연마 전후의 물접촉각 및 SEM, XRD를 측정하였다. 실란/실록산계 혼합형 발수제를 혼입한 시멘트 페이스트의 플로우는 발수제 혼입량을 1.0%씩 높일수록 증가하였다. 실란/실록산계 혼합형 발수제를 혼입할 경우 시멘트 페이스트의 응결시간은 초결 및 종결 모두 지연되는 것으로 나타났다. 이러한 지연은 소수성에 기인하여 실란/실록산계 발수제를 클링커 입자 근처에 배치하여 소수성 장벽을 생성하기 때문이다. 실란/실록산계 혼합형 발수제를 시멘트 페이스트에 0.5% 혼입할 경우 압축강도는 증가하였으나 혼입량이 1.5%, 3.0% 증가할수록 압축강도는 감소하는 것으로 나타났다. 최대 혼입량 3.0%일 경우 압축강도는 최대 8.3%까지 감소하는 것으로 나타났다. 이는 발수제가 시멘트의 수화를 지연 및 방해하여 압축강도가 저하된 것으로 판단된다. 실란/실록산계 발수제를 시멘트 페이스트에 혼입할 경우 친수성이 개선되며 소수성을 나타내 접촉각이 커지는 것으로 나타났다. 또한 표면연마 후 접촉각은 표면연마 전보다 커지는 것으로 나타났다. 실란/실록산계 혼합형 발수제의 혼입은 표면뿐만 아니라 연마로 인하여 손상된 표면과 단면에서도 소수성을 나타내었다. The aim of this paper is to improve durability of cement paste by imparting hydrophobicity to the surface and sphere of cement-based materials. A cement paste mixed with a silane/siloxane-based water repellent, and the initial hydration performance, flow performance, and age-specific compressive strength were measured. In addition, the water contact angle, SEM, and XRD before and after surface polishing were measured. When 0.5% of the silane/siloxane-based water repellent was mixed into the cement paste, the compressive strength increased, but the compressive strength decreased as the mixing amount increased by 1.5% and 3.0%. When a silane/siloxane water repellent was incorporated into the cement paste, the hydrophilicity was improved and the contact angle was increased due to hydrophobicity. In addition, the contact angle after surface polishing was found to be larger than the contact angle before surface polishing.

표면 성상에 따른 수용성 발수제 혼입 시멘트 모르타르의 발수특성

강석표 ( Suk-pyo Kang ),강혜주 ( Hye-ju Kang ),홍성욱 ( Seong-uk Hong ),양승현 ( Seung-hyeon Yang ) 한국구조물진단유지관리공학회 2020 한국구조물진단유지관리공학회 논문집 Vol.24 No.6

본 논문은 시멘트계 재료의 표면 및 구체에 소수성을 부여하여 내구성을 향상시키기 위한 기초연구이다. 실란/실록산계 혼합형 발수제를 첨가한 시멘트 모르타르를 제조하고 초기 수화성능 및 유동성능, 재령별 압축강도를 측정하였다. 또한 표면연마 전후의 물접촉각 및 흡수율을 측정하였다. 실란/실록산계 혼합형 발수제를 첨가한 시멘트 모르타르의 플로우는 발수제 첨가량 1.5%까지는 감소하는 것으로 나타났으며 첨가량 3.0%에서는 증가하였다. 실란/실록산계 혼합형 발수제를 첨가할 경우 시멘트 페이스트의 응결시간은 초결 및 종결 모두 지연되는 것으로 나타났다. 압축강도는 발수제의 최대 첨가량 3.0%에서 최대 30%까지 감소하는 것으로 나타났다. 실란/실록산계 발수제를 시멘트 모르타르에 첨가할 경우 접촉각은 커지는 것으로 나타났으며, 표면연마 후 접촉각은 표면연마 전보다 커지는 것으로 나타났다. 실란/실록산계 혼합형 발수제의 첨가는 표면뿐만 아니라 연마로 인하여 손상된 표면과 단면에서도 소수성을 나타내었다. 실란/실록산계 혼합형 발수제를 시멘트모르타르에 첨가할 경우 흡수율은 낮아지는 것으로 나타났으며, 표면연마 후 흡수율은 표면연마 전보다 커지는 것으로 나타났다. This paper is a basic study to improve durability by imparting hydrophobicity to the surface and sphere of cement-based materials. A cement mortar to which a silane/siloxane-based mixed water repellent was added was prepared, and its initial hydration performance, flow performance, and compressive strength were measured. In addition, after the surface was abraded, the water contact angle and water absorption were measured. The flow of cement mortar to which the water repellent was added was found to decrease up to 1.5% in the addition amount of the water repellent agent, and increased at 3.0% in the addition amount. It was found that the setting time of the cement paste was delayed in both the initial setting and the termination when the water repellent was added. It was found that the compressive strength decreased from 3.0% of the maximum added amount of the water repellent to a maximum of 30%. The contact angle was found to increase when the water repellent was added to the cement mortar, and the contact angle after surface polishing was found to be larger than before surface polishing. The addition of the water repellent showed hydrophobicity not only on the surface but also on the surface and cross section damaged by polishing. The water absorption rate was found to decrease when the water repellent was added to the cement mortar, and the water absorption rate after surface polishing was found to be greater than before surface polishing.

콘크리트에서의 n-octyl ethoxy silane 발수제의 성능평가

황인동,이완조,염희남,정윤중 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.12

최근 콘크리트 보호 재료는 코팅을 이용하는 과거의 방법에서 함침을 이용하는 기법으로 전환하였다. 이중 발수제는 콘크리트의 표면의 특성을 변화시키는 것으로 친수성의 콘크리트를 소수성 물질을 결합시켜 물에 의한 젖음을 방어하는 것으로 콘크리트에 사용하였을 경우 콘크리트의 고유한 표면 장력을 작게 변화시키고 장력이 큰 물질 중의 하나인 물의 흡수를 방어하게 한다. 본 실험은 발수제의 성능 평가를 위하여 다공질의 재료인 콘크리트의 접촉각을 측정하여 그 변화를 관찰하였으며, 발수제들의 우수한 기능 중의 하나인 통기성을 시편의 중량 감소로 측정하였다. 발수제로 n-octyl ethoxy silane을 사용한 콘크리트 시편의 흡수 능력은 사용하지 않은 것의 약 10% 정도로 측정되었으며 시편의 수분 중량 감소는 7일 동안 90~130%로 관찰되어 통기성이 유지되어 콘크리트의 강도 유지에 효과적임을 알 수 있었다. 또한 겉보기 접촉각은 처리하지 않은 시편에서 24~33$^{\circ}$로 측정되었으나 처리된 시편의 최초면에서 130~141$^{\circ}$이었으며 2mm의 연마면에서는 127~132$^{\circ}$로 측정되어 콘크리트 표면 장력 변화가 유지되고 있음을 알 수 있었다.

The effect of surface silanization on selective catalytic reduction catalysts

이민성,김선이,김태효,이덕현 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Recently, the regulations of atmospheric pollutants have been tightened in the environmental field. NOx is a generic term for the nitrogen oxides that are most relevant for air pollution. Selective catalytic reduction (SCR) catalysts have been used to remove NOx. Commercially, V2O5- WO3/TiO2 catalyst were applied for the SCR catalysts, however, they have been suffered with low NOx removal efficiency under the presence of water. In this study, the surface of SCR catalyst was treated with silanization process. The SCR catalyst was synthesized by impregnation method, and the surface of SCR catalyst was coated through the vaporization of silane. The synthesized catalysts were evaluated through fixed bed reactor, and they were characterized by SEM, XRD, NH3-TPD, and FT-IR. The prepared catalyst showed enhanced NOx removal efficiency compared to the raw SCR catalyst, and the process may be applied to the various fields that require the hydro-resistive properties of catalytic surface.

17α-Ethinylestradiol elimination using synthesized and dense nanocomposite materials: Mechanism and real matrix treatment

Ralte Malsawmdawngzela,Diwakar Tiwari 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.3

Endocrine disrupting chemicals (EDCs) are emerging water contaminants and efficient elimination is a greater challenge for environmental engineers. The present communication is intended to synthesize the novel dense nanocomposite materials precursors to the bentonite and 3-mercaptopropyletrimethoxy silane/or 3-aminopropyletriethoxy silane. The materials are highly dense, hence the surface area is significantly reduced compared to the pristine bentonite. Further, the materials are intended to be utilized in the elimination of one of the important EDC 17α- ethinylestradiol (EE2). The sorption mechanism is greatly demonstrated based on various parametric studies. It is shown that grafted silane with bentonite network provides enhanced hydrophobicity with organophilic nature and greatly favors the uptake of EE2 at a wide range of pH (5.0-10.0). Relatively rapid uptake of EE2 by the nanocomposite solids followed by a pseudo-second-order kinetic model indicated that the materials are highly efficient for elimination of EE2. Increasing the concentration of EE2 (1.0 to 10.0 mgL-1 ) favored the extent of removal of EE2 and followed the Langmuir adsorption isotherm. Further, the increase in background electrolytes by 1,000 times did not affect the removal of EE2 by these nanocomposites, indicating the sorbing species are attracted with relatively stronger forces. Moreover, the simultaneous presence of several co-ions did not affect the percentage elimination of EE2; this, perhaps, shows an enhanced selectivity of materials towards the 17α-ethinylestradiol. A high loading capacity of EE2 is achieved under column reactor operation using these nanocomposites. Additionally, the materials are promising in the real matrix treatment.

Improvement in the Superhydrophobicity of Cellulose Aerogels Using Cationic Polymers

정명준,양봉숙,강규영 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.2

In this study, a cross-linked cellulose aerogel was rst prepared using a cellulose wet-gel treated with a mixture of cationic poly (aminoamide)-epichlorohydrin and vinyl acetate ethylene copoly- mer. Following this, a cross-linked superhydrophobic cellulose aerogel was successfully fabricated using a simplied silanization process. The silane-coated cellulose aerogel exhibited an excellent oil absorption capacity (18 to 65 times the dry weight of the cellulose aerogel) without water absorp- tion, and the recovered dimensions of the cellulose aerogel after compression were improved via the cationic polymer treatment. This material, thus, exhibits great potential as an oil absorbent.

접합 판형 열교환기(BPHE)의 내부 코팅에 따른 소재 특성 및 성능 평가에 관한 연구

정항철,양현석,김현종,박종포 한국결정성장학회 2020 韓國結晶成長學會誌 Vol.30 No.6

In this study, a silane-based coating was applied to improve corrosion resistance and thermal efficiency performanceof a brazed plate heat exchanger (BPHE) composed of stainless plate and copper (Cu) brazing. Although the selected coatingmaterial was applied to the BPHE by evaluating the corrosion and contact angle according to the coating material, theresult of the heat transfer performance evaluation showed that the thermal efficiency was lower than that of the uncoatedBPHE. It was analyzed that the adhesion of the coating agent to the flow path inside the BPHE and the residual coatingagent on the surface acted as heat resistance, preventing heat transfer. This is due to the structural characteristics of theBPHE in which a fine flow path exists inside, and it is believed that manufacturing after coating the surface of the flowpath in advance in the manufacturing process of the BPHE can improve heat transfer performance. 본 연구에서는 STS-316 플레이트와 구리(Cu) 브레이징으로 구성된 접합 판형 열교환기(BPHE, Brazed PlateHeat Exchanger)의 내식성과 열효율 성능 향상을 위해 실란계 코팅을 적용하고자 하였다. 코팅 재료에 따른 부식 및 접촉각을 평가하여 선정된 코팅재료를 열교환기에 적용하였으나, 전열 성능 평가 결과 코팅하지 않은 열교환기에 비해 열효율이떨어지는 결과가 나타났다. 이는 접합 판형 열교환기 내부의 유로에 코팅제의 고착화 및 표면의 잔여 코팅제가 열저항으로작용하여 열전달을 방해는 것으로 분석되었다. 이는 내부에 미세한 유로가 존재하는 판형 열교환기의 구조적인 특성에 기인한 것으로, 판형 열교환기 제작 공정에서 사전에 유로 표면에 코팅 후 제작하는 것이 전열성능을 향상 시킬 수 있을 것으로 판단된다.

Electrorheologicalactivities of various silane-treated pearl pigments

김지원,윤창민 한국공업화학회 2022 한국공업화학회 연구논문 초록집 Vol.2022 No.-

비용매 기상증착으로 표면처리된 실리카 나노입자와 폴리메틸메타크릴레이트를이용한 발수 스프레이 코팅

박소정,박민아,정수빈,이예린,정민수,박영돈 한국고분자학회 2023 폴리머 Vol.47 No.6

Hydrophobic water-repellent coating is a key technology for controlling surface properties and protecting sur-faces not only in industrial fields but also in everyday life. Since the hydrophobic surface has functionalities such as self-cleaning, anti-corrosion, and anti-fouling as well as waterproof, it plays a role in protecting the surface and increasing durability in various fields. In this study, the surface of hydrophilic silica nanoparticles was modified to be hydrophobic through non-solvent vapor deposition. A simple spray coating formulation was developed by dispersing silica nanopar-ticles in a solvent together with a polymer binder, poly(methyl methacrylate). The surface morphology, roughness, and transmittance were investigated with the silica nanoparticle size, solvent type, and polymer concentration, and the hydro-phobic surface was optimized by measuring the water contact angle.