• Corrosion Science and Technology
• /
• v.18 no.6
• /
• pp.228-231
• /
• 2019

Aluminum and its alloys have been widely used in various fields because of low weight, high strength, good conductivity, and low price. It is well known that aluminum alloys that cause natural oxide film can inhibit corrosion in wet, salty environments. However, these oxides are so thin that corrosion occurs in a variety of environments. To prevent this problem, an electrochemical anodizing technique was applied to the aluminum alloy surface to form a thick layer of oxide and a unique oxide shape, such as a hierarchical pore structure simultaneously combining large and small pores. The shape of the structures was implemented using stepwise anodization voltages such as 40 V for mild anodizing and 80 V for hard anodizing, respectively. To maximize water repellency, it is crucial to the role of surface structures shape. And a hydrophobic thin film was coated by 1H, 1H, 2H, 2H-Perfluorodecyltrichlorosilane (FDTS) to minimize surface energy of the structure surface. Thus, such nanoengineered superhydrophobic surface exhibited a high water contact angle and excellent corrosion resistance such as low corrosion current density and inhibition efficiency.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.18 no.5
• /
• pp.674-681
• /
• 1994

In this study, four kinds of vapor-permeable waterproofed fabrics were selected and their properties and the changes of properties were investigated after laundering, petroleum drycleaning or tetrachloroethylene drycleaning (each 1, 5, 10 times). The results were as follows: 1) In the water resistance, only Gore Tex satisfied its minimum property requirements, $1.0kg/cm^2$ It decreased after laddering and drycleaning. Hipora-1000, Hipora-2000, Aitac decreased slightly by petroleum drycleaning and Gore Tex decreased slightly by all three methods. 2) In the moisture vapor transmission, three except Hipora-2000 satisfied its minimum property requirement, $4000g/m^2{\cdot}24hr$.24hr. After laundering and drycleaning, it increased regardless of cleaning methods. 3) In the water repellency, Hipora-lOOG, Hipora-2000 were not almost decreased after laundering and drycleaning. Aitac decreased slightly by petrolem drycleaning and Gore Tex decreased slightly by laundering and petroleum drycleaning. 4) Air permeability of Aitac increased with increasing of cleaning times regardless of cleaning methods. 5) In the bond strength, only Gore Tex dissatisfied its minimum property requirements, 250g/cm. Regardless of cleaning method, bond strength decreased with increasing of cleaning times. 6) Color difference was large in case of Hipora-1000 by laundering, Hipora-2000 by laundering and tetrachloroethylene drycleaning Aitac by tetrachloroethylene drycleaning, Gore Tex by laundering. To diminish property change of vaper-permeable waterproofed fabric, petroleum drycleaning is more effective than laundering and tetrachloroethylene drycleaning.

• Transactions of the Korean hydrogen and new energy society
• /
• v.20 no.5
• /
• pp.424-431
• /
• 2009

Treatment for water repellency on the carbon supports of GDL which composed a part of MEA has been suggested as a solution to prevent flooding. PTFE is a fluoropolymer that has hydrophobic property and a PTFE emulsion was selected as waterproof agent in this investigation. Carbon paper was coated by PTFE emulsion with different particle size of 5~500 nm and 3~$5\;{\mu}m$ as various concentration. PTFE coated carbon paper has difference in weight variation changed proportionally at PTFE concentration and coating times. Then gas permeability of the coated carbon paper with emulsion of 3~$5\;{\mu}m$ PTFE was changed vastly. Characteristics of carbon paper coated with different PTFE emulsion were analyzed by FE-SEM, FT-IR spcetroscopy and were evaluated by weight variations, gas permeability and water contact angle.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.41 no.3
• /
• pp.527-536
• /
• 2017

This study investigated the detergency and functionality of laminating finished fabrics for outdoor wear based on repeated washing. Laminating finished fabrics were selected as the main fabrics for outdoor wear and used as test fabrics. The effects of outdoor exclusive detergent and normal neutral detergent were examined according to washing time, temperature, rpm and detergent concentration based on the use of a Terg-O-Tometer. Re-soiling of the test fabrics was measured by Florio-Mersereau. Permeability, water repellency, water resistance and absorbency were estimated to measure improvements and effects in regards to outdoor exclusive detergent in optimal washing conditions. The detergent effect of outdoor exclusive detergent was superior compared to normal neutral detergent. Re-soiling was lower with exclusive outdoor detergent than with normal neutral detergent. The measurement of functionality for laminating finished fabrics before and after washing indicated that functionality was decreased with repeated washing.

• Journal of the Korean Wood Science and Technology
• /
• v.22 no.4
• /
• pp.13-18
• /
• 1994

Sapwood samples of pitch pine were treated with disodium octaborate alone by dip-diffusion, or in combination with water-repellent preservative(WRP) and methyl metacrylate(MMA). Treated samples were subjected to an accelerated leaching test for determining the improvement of leaching resistance and to soft rot and mold tests for evaluating the increase in bioefficacy, due to the addition of WRP and MMA applied as a second treatment. The addition of WRP and MMA retarded leaching of boron to some extent from treated samples and this retardation can be explained by improved water repellency of WRP and MMA treated samples. Borate /WRP and borate /MMA systems will not qualify borate treated wood for ground and fresh water contact use but may improve performance of borate treated wood in above-ground applications not subjected to continuous wetting conditions. Bioefficacy against soft rot fungi and mold fungi was improved by a second treatment with WRP. However, improvement in the performance of borate /MMA systems was not observed. Considering improvement in both resistance of leaching and bioefficacy against micro fungi by the treatment of WRP and MMA, simultaneously, the dual treatment of borate treated wood by MMA containing co-biocides might be believed as an ideal treatment system.

• International Journal of Highway Engineering
• /
• v.19 no.2
• /
• pp.7-15
• /
• 2017

PURPOSES : Infiltration of moisture, polluted material, and deicer into concrete, accompanied by freeze and thaw can cause significant deterioration of concrete pavement. In order to protect concrete from deterioration, it is necessary to prevent the infiltration of these concrete external materials. The moisture-repellent agent, which is a surface treatment and maintenance material added to concrete structures to render them water resistant, has advantages such as prevention of water infiltration and security against air permeation. Nano-coat, which is referred to as silicon hydride, is typically used as a moisture-repellent agent. Therefore, in this study, an attempt is made to use penetration-type Nano-coat as an alternative in order to evaluate its applicability through environmental resistance tests. METHODS : This study aimed to evaluate the applicability of penetration-type Nano-coat, which can provide water repellency to concrete, in concrete pavements, through various environmental resistance tests such as freezing and thawing resistance, chloride ion penetration resistance, and surface scaling resistance tests. The applicability of penetration-type Nano-coat was demonstrated based on the specification of KS F 2711, KS F 2456, and ASTM C 672. RESULTS :In the case of penetration-type Nano-coat applied on sound concrete, an increase in concrete durability was demonstrated by the negligible chloride ion penetrability and the absence of scaling, as revealed by visual observation of the surface, after 50 cycles of scaling resistance test. In addition, test result of the application of penetration-type Nano-coat on deteriorated concrete established that concrete surface pretreated by grinding provided improved durability than non-treated concrete. CONCLUSIONS :This study indicates that penetration-type Nano-coat is applicable as an effective alternative, to increase the durability of concrete structures. In addition, it was known that pretreatment of deteriorated concrete surface, such as grinding, is required to improve the long-term performance of concrete pavement.

• Applied Microscopy
• /
• v.42 no.2
• /
• pp.95-103
• /
• 2012

The cell surface sculpture of the plant epidermis has received great interest recently. It has also been an active area of research, as the biological microstructures of the surface, such as papillae and waxes, exhibit several unique properties, including self-cleaning character; namely the "Lotus effect" first described in the leaves of the lotus, Nelumbo nucifera. The Lotus effect is the phenomenon in which the super-hydrophobic and water-repellent nature of lotus leaves allow water drops to run off easily on the surface in a rolling and sliding motion thereby facilitating the removal of dirt particles. It is well-known that surface roughness on the micro- and nanoscale is a primary characteristic allowing for the Lotus effect. This effect is common among plants and is of great technological importance, since it can be applied industrially in numerous fields. In the present study, Nelumbo nucifera leaf and stem epidermal surfaces have been examined with a focus on the features of papillae and wax crystalloids. Both young and mature Nelumbo nucifera leaf epidermis demonstrated the Lotus effect on their entire epidermal surface. The central area of the upper epidermis, in particular, formed extremely papillose surfaces, with an additional wax layer, enabling greater water repellency. Despite the presence of wax crystalloids, epidermal surfaces of the lower leaf and stem lacking papillae, were much more easily wetted.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.4
• /
• pp.31-36
• /
• 2019

Concrete is a material generally used to build structures and it is exposed to various environment conditions. In particular, a medium such as water lets noxious factors flow into concrete, causing a lot of damage. Therefore, different kinds of materials are being developed to increase the durability of concrete. Among such materials, silane and siloxane compound are known to have a high utilization as an absorption inhibitor. However, if aged or deteriorated reinforced concrete is treated with those compounds, they easily come off the concrete and lose their function since the basic material is weak. This study conducted an experiment to provide concrete with both an absorption-inhibiting effect and surface strengthening by using melamine-formaldehyde resins that are surface-treated with siloxane compound. In addition, a study on the porosity and surface hardness characteristics of a concrete was conducted to check the absorption-inhibiting effect and surface strengthening.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.1
• /
• pp.45-51
• /
• 2015

The anti-fungal activity of plant extractives was investigated and the lacquer extractives were selected. The lacquer extractives were coated on anti-fungal paper and confirmed its effect. Water repellency, tensile index and brightness of anti-fungal paper treated with natural extractives were similar to commercial pesticide-treated paper. The incidence of Fusicaladium leuieri MAGNUS of commercial pesticide-treated paper and anti-fungal paper treated with lacquer were similar but, the incidence of Botryosphaeria dothidea (Moug.) Ces & De Not and Gloeodes pomigena of those were increased 10-60 % than commercial pesticide-treated paper.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.41 no.5
• /
• pp.901-913
• /
• 2017

This study analyzed the current state of art by investigating related patents of cycling wear, and suggested fundamental data to develop clothing - originated in Korea. Patent trends were then analyzed after the related patents applied in Korea, USA, and Japan from 1975 to 2015 were extracted using WIPS ON, classified as nation, applicant, technology, use, and technological maturity of the applicant country. The number of patent applications has steadily increased since the 1990s, and has steeply grown since the 2000s. The USA accounted for 55.6% of all collected patents in the study, Japan for 30.6%, and Korea for 13.7%. Technologies related to patterns and functional materials have been dominated by the USA and Japan; however, smart technologies have been actively developed in Korea. According to use, USA focused on functionality, Korea concentrated on safety, and Japan uniformly combined functionality, safety, and convenience. According to the positioning of technology by application, water repellency, stretchability, muscle strengthening, pad, panel, finishing, and weaving technologies were positioned in the functionality.