• Transactions on Electrical and Electronic Materials
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• v.18 no.4
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• pp.203-206
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• 2017

The effect of the content of microsilica and nanosilica continuously modified with hydroxy silane and epoxy-modified silicone in cycloaliphatic epoxy/microsilica/nanosilica composites (EMNCs) on the mechanical and water repellent properties was evaluated. Surface-modified micro- and nanosilica was well-mixed with a cycloaliphatic epoxy resin in the presence of polyester-modified polydimethylsiloxane (PEM-PDMS) as a dispersing agent using an ultrasonicator. Tensile and flexural tests were carried out using a universal testing machine (UTM). The water repellent property was evaluated by contact angle measurements of water on the composite surface. Tensile strength of the composite could be enhanced by 32.2% up to 91.4 MPa, and the flexural strength was raised to 122.0 MPa, which is 38.8% higher than that of neat epoxy. The contact angle of water on the composite was as high as $104.1^{\circ}$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.76-77
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• 2021

compared and reviewed the water repellency and strength characteristics by controlling the surface stamping size and fine aggregate ratio of cement mortar mixed with water repellent as a method to control the ecological imitation surface structure. As a result of measuring the contact angle, the higher the ratio of fine aggregate, the larger the contact angle. The contact angle increased when the surface structure was changed by stamping, and increased as the stamping size became smaller. In the surface stamping of mesh#150, the contact angle was particularly increased.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.152.1-152.1
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• 2005

• Fashion & Textile Research Journal
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• v.22 no.1
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• pp.112-118
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• 2020

This paper examined the water repellency, water proofing and water vapor permeability of twelve types of woven fabrics for sports wear clothing. Their physical properties were compared and discussed with the fabric structural parameters and surface finishing effect. A water repellent property of 100% was obtained in the coated or laminated water repellent finished fabrics; in addition, cotton/nylon breathable composite fabrics treated with a laminated finishing and with low fabric density showed a 90% water repellency. Water proofing fabric above 6,000 mm H₂O hydraulic pressure was achieved by coated or laminated finishing; however, high density fabric or medium-level coated fabrics exhibited 100% water repellent and low water proofing characteristics. Superior water vapor permeability characteristics with good water repellency and proofing properties were achieved at the 2.5 layered low density and with 0.7 - 0.9 cover factor nylon fabrics treated with hydrophilic laminated finishing. The regression analysis for examining the effects of fabric structural parameters and surface finishing such as coating and laminating to the water vapor permeability exhibited a high determination coefficient of fabric structural parameters of 63.5%; in addition,, main factors among fabric structural parameters appeared to be cover factor and fabric thickness per weight. Coating and Laminating factors exhibited determination coefficient of water vapor permeability parameters of 36.5%.

• Journal of the Korean Home Economics Association
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• v.20 no.3
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• pp.19-24
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• 1982

This study was carried out to investigate the relationship between the water resistance and the air permeability. The results are as follows; 1. In case of the water proofing fabrics, We cannot find that there is any relationship between the water resistance and the air permeability according to the kinds of finishing, while in case of the water repellent finished fabries, we can find that there is a correlationship between them, especially the hydrostatic pressure and the air permeability are found to have negative correlation. 2. In case of the water proofing fabrics, the relationship between the water resistance and the air permeability is not affected by the thickness of the fabrics. On the other hand, in case of the water repellent finished fabrics, the relationship between them is affected by the thickness of the fabrics. Especially, the relationship between the hydrostatic pressure and the air permeability as well as the relationship between the water repellency and the air permeability is effect much by the thickness of the fabrics, too. 3. In case of the water proofing fabrics, the relationship between the water resistance and the air permeability is not affected by fabric count. On the otherhand, in case of the water repellent finished fabrics, the relationship between them is affected by the fabric count. Especially, the relationship between hydrostatic pressure and the air permeability, and the relationship between the water proof and the air permeability are affected much by fabric count.

• 보존과학연구
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• s.22
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• pp.133-154
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• 2001

Stone cultural properties, exposed in natural environment, is deteriorated by many weathering reasons for a long time. It is necessary to treat of consolidation and water-repellent on the surface because of the conservation of stone cultural properties. We was treated the specimen [granite(Hwangdung-suk), sandstone, marble(in JeongSeon)] by synthesis resin of DWR-Ⅲ, SI2121 and fluoropolymer, and tested on the durability, water-repellent, color stability and luster generation etc. In the result of this study, DWR-Ⅲ and fluoropolymer is superior to the waterrepellent, durability of salt and acid rain. SI2121 is superior to the penetration because of lower viscosity, but the water-repellent is inferior to the others. After the treatment of chemicals, the color-variation make an appearance but luster-generation doesn’t. With the passage of time, the color of specimen was got better because of the ‘washing’ phenomenon for ultra-violet, salt etc.

• Journal of Forest and Environmental Science
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• v.29 no.2
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• pp.109-115
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• 2013

Fast-grown wood generally contains a high proportion of juvenile wood that results in inferior dimensional stability and durability against biological deteriorations. In the present research, the Acacia mangium wood from plantation forests in Vietnam was treated with high temperature in air. The effects of heat treatment on physical properties of Acacia mangium wood, including mass loss (ML), water absorption (WA), water-repellent effectiveness (WRE) and anti-swelling efficiency (ASE) were examined. The results showed that the dimensional stability and the water-repellent effectiveness are increased by about 15-46% and 8-18%, respectively. However, the mass and dimension of wood are decreased. The results also indicated that both treatment temperature and treatment duration significantly affect the wood properties of Acacia mangium. It is thus concluded that heat treatment demonstrates an interesting potential to improve the wood quality of Acacia mangium for solid timber products. This technology provides an environmentally safe method of protecting sustainable common woods to give a new generation of value-added biomaterials with increased stability without the use of toxic chemicals.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.607-614
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• 2015

Generally surface finishing of building is done with water paint that performs basic water repellency and resisting. When painting the exterior of the building with water paint, application method is easy and inexpensive and it has the advantage of building maintenance. But surface finishing of water paint is easy to discolored or aging due to ultraviolet light so the effect is not satisfying than expected. Therefore this study is to analyze durability of water-repellent paints mixed with water-repellents as outer surface finishing materials, and evaluate its feasibility. Color change and color different due to the accelerated time were tested, and the feasibility was evaluated based on the test results. The experimental results of color different, brightness different and chromaticity suggested that water-repellent paints mixed with water-repellents were suitable for finishing materials. Considering overall general durability performances, stable mixing ratios were 2, 5, and 8%.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.327-334
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• 2018

Water-repellent coating solutions were prepared by sol-gel method using tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMS) as precursors. The solutions were spin-coated on a cold-rolled steel sheet and thermally cured to prepare a non-fluorine water-repellent coating films. The effects of molar ratios of MTMS/TEOS, water concentration and ammonia concentration on the hydrophobic properties of the coating films were studied. The contact angle of water on coating films prepared by varying the molar ratio of MTMS/TEOS to 1~20 showed a maximum value of $108^{\circ}$ when the MTMS/TEOS molar ratio was 10. With increasing water content, the coating films showed the larger contact angles and the better the water repellency. As the amount of ammonia added was increased, the contact angles of coating films were increased, showing the better the water repellency. It is considered that the larger the amount of ammonia added, the larger the size of the silica particles generated, which increases the surface roughness of the silica particles, thereby increasing the water repellency.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.4
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• pp.577-586
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• 1993

Pesticide protective clothing has not been frequently worn due to its lack of thermal comfort. It is important to develop fabrics which can allow the wearer to work in comfort. One of the possible way to achieve the goal is to produce fabrics with a water- and oil-repellent finish which would resist pesticide penetration but maintain some breathability. The purpose of this study were to evaluate the pesticide barrier properties of untreated and water- and oil-repellent finished nonwoven fabrics. Three types of nonwoven fabrics(Tyvek, Sontara and Kimlon) were used as test specimens. By pad-dry-cure method, each of the specimen was treated with fluorocarbon. The pesticide barrier properties (amount of pesticide penetration and residue) were measured by the gas chromatography. The performance properties of untreated and treated specimens were evaluated with respects to water pepellency(KS K 0590), oil repellency(AATCC 118), water resistance(KS K 0591, AATCC 42), water vapor transmission (KS A 1013) and air permeability(KS K 0570). The results of this study were as follows : 1) The untreated Sontara showed much more amount of pesticide penetration than untreated Tyvek and Kimlon, while the treated Sontara showed little amount of pesticide penetration. 2) After laundering, the amount of pesticide residue in the untreated and treated Sontara was less than that in Tyvek and in Kimlon. 3) Water- and oil-repellent finish improved water repellency, oil repellency, and water resistance of specimens. 4) The untreated Sontara and Kimlon showed higher water vapor transmission and air permeability than untreated Tyvek. Water vapor transmission and air permeability of treated specimen decreased compared to those of untreated.