• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1605-1607
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• 1999

Silicone rubber have presently been using in large number for a variety of outdoor HV applications. Silicone rubber have the properties of low surface energy and are able to retain its hydrophobicity or water repellency, thereby suppress the leakage current in the present of moisture and contamination. In this paper, we investigated the recovery characteristics of silicone rubber by measuring the leakage current under salt-fog.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1651-1653
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• 1999

Room Temperature Vulcanizing (RTV) Silicone Rubber has been widely used to coat porcelain insulator to prevent formation water filming on insulator surface. and RTV silicone rubber has water repellency to suppress leakage current and consequent flashover. RTV silicone rubber's surface has been degradated by outdoor condition such as dust, salt, and water. etc. ESDD(Equivalent Salt Deposit Density) and leakage currents are increased by polymer surface toughness and degradation. In this paper, we investigated relations of surface toughness, ESDD, and leakage currents.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.6-8
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• 2001

This report describes the effect of the blending of poly(trifluoropropylmethylvinylsiloxane) (PTFPMVS) with poly(dimethylsiloxane) (PDMS) on the surface properties such as water repellency using dynamic contact angle (DCA) measurement. We have investigated the surface molecular mobility of the PDMS/PTFPMVS blends via a DCA measurement and an adhesion tension relaxation. It could be shown that a flexible side-chain segment in PTFPMVS having higher surface energy, could be reoriented easily in water to decrease the interfacial tension of the polymer/water interface, which seems to play a major role at the decrease of the receding contact angle and the surface resistivity of PDMS/PTFPMVS blends.

• Wind and Structures
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• 제6권6호
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• pp.471-484
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• 2003

The rain-wind induced vibration of stays is a phenomenon discovered recently and not well explained yet. As it is influenced by a wide range of physical parameters (cable size and shape, wind speed, direction and turbulence, rain intensity, material repellency and roughness, cable weight, damping and pre-strain), this peculiar phenomenon is difficult to reproduce in laboratory controlled conditions. A successful wind tunnel experimental campaign, in which some basic physical quantities were measured, allowed an extensive analysis as to identify the parameters of the rain-wind induced excitation. The unsteady pressure field and water thickness around a cable model were measured under rainy-excited conditions. The knowledge of those parameters provided helpful information about the air-flow around the cable and allowed to clarify the physical phenomenon which produces the excitation.

• Weed & Turfgrass Science
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• 제3권4호
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• pp.336-341
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• 2014

Wetting agent is a substance that reduces the soil water repellency and causes a liquid to spread more easily into the soil. Wetting agents are well known as to improve irrigation efficiency. Phosphorus is one of the 17 essential nutrient elements and promote faster seed germination. The objective of this study was to evaluate wetting agent and P rates for fast germination and establishment of Kentucky bluegrass. Three levels of wetting agent which were 0.23, 0.46, and $0.92ml\;m^{-2}$ were applied and the P treatments were 5, 10, and $15g\;m^{-2}$. The medium and high rate of wetting agent at the high P rate had the greatest turfgrass coverage and took 28 days to reach 50% turfgrass coverage regardless of P application. Based on this study, wetting agent is effective for fast germination and establishment of Kentucky bluegrass if sufficient phosphorus is applied.

• 한국염색가공학회지
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• 제31권4호
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• pp.276-287
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• 2019

In this study, cotton fibers were coated with a different weight percentage of octadecyl dimethyl(3-triethoxy silylpropyl) ammonium chloride(ODDMAC) to improve antimicrobial and water repellent properties. First, the ODDMAC dissolved in ethanol to prepare a solution. Then the cotton fibers were immersed in the ODDMAC/ethanol solution for 10 minutes at ambient temperature and dried at 80℃ for 3 minutes followed by curing. The treated cotton fibers were characterized by scanning electron microscopy(SEM) and x-ray photoelectron spectroscopy(XPS). The treated cotton fibers revealed sufficient antimicrobial activity against Klebsiella pneumoniae(ATCC 4352) and Staphylococcus aureus(ATCCBAA-1707). The hydrophobic nature of the treated cotton fibers was characterized by contact angle measurement. The results showed that the cotton fibers treated with the ODDMAC showed excellent hydrophobic properties which improved to 121°.

• 한국응용과학기술학회지
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• 제5권1호
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• pp.63-70
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• 1988

The quaternized compound of the copolymer between 2-diethylaminoethyl methacrylate and stearyl methacrylate (DSACC) was chosen as the mother resin for the water repellent of acrylics. The quaternized compound of 1-lauroyl dis (amino ethyl)-2-dodecyl imidazoline (LDDIC) was used to promote softening effect and hydrostatic pressure for the water repellent. The water repellent (EDUWC) obtained from the DSACC and LDDIC blended with waxes and emulsifiers improved the properties such as the water repellency, washable, tear strength and crease recovery when it was treated on the nylon fabrics with and without the resin. The reaction mechanism between the Nylon fiber and EDLWC was examined, and EDLWC was confirmed as the durable water repellent.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.866-868
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• 1998

Room temperature vulcanizing(RTV)silicone rubber has been widely used to coat porcelain insulators to render water repellency to prevent formation of water filming on the surface and thus to suppress the leakage current and consequent flashover. However, the electrical property and its hydrophobicity of RTV silicone rubber coating under outdoor conditions may be influenced by many environmental factors. In this study various treatments, such as salt-fog, salt water immerging and UV irradiation were applied to samples for investigation the change of the electrical property and hydrophobicity. As a result the leakage current increased and contact angle decreased as the degradation time longer. But the degraded RTV silicone rubber has recovered its hydrophobicity during the drying time in ambient condition because LMW(Low Molecular Weight)silicone fluid diffused from the bulk to the surface.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.112-113
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• 2014

This study was done to resolve the air reduction in mortar when mixed with ERCO. Effects of the water repellent ALC powder due to its particle size and substitution ratio on the cement mortar with ERCO was analyzed. Results showed more water repellent ALC powder ensured more air but did not affect the size of particles. It was determined the compression was caused by more air and water added to achieve the flow. Therefore, substituting with water repellent ALC powder may compensate for the air reduction in mortar with ERCO. Other measures and approaches are needed in order to resolve the reduced strength.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권6호
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• pp.462-468
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• 1999

Room temperature vulcanizing (RTV) silicone rubber has been widely used to coat porcelain insulators to render water repellency to prevent formation of water film on the surface and thus to suppress the leakage current and consequently flashover. However, the electrical property and the hydrophobicity of RTV silicone rubber coating under outdoor condition may be influenced by many environmental factors. In this studyvarious treatments, such as salt-fog, salt water immerging and UV irradiation were applied to the samples to investigate the change of the electrical property and hydrophobicity. As a result the leakage current increased and contact angle decreased asthe degradation time is longer. But the degraded RTV silicone rubber has recovered its hydrophobicity during the drying time in ambient condition because LMW(Low Molecular Weight) silicone fluid diffused from the bulk to the surface.