• Title/Summary/Keyword: water-vapor permeability

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Study on Ultra Porous Aerogel/fiber Composite for Shoe Insole (초다공성 에어로젤 함유 섬유상 복합체를 이용한 신발 안창소재에 관한 연구)

  • Oh, Kyung-Wha;Park, Soon-Ja
    • Journal of the Korean Society of Clothing and Textiles
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    • v.33 no.5
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    • pp.701-710
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    • 2009
  • This study was conducted to develop excellent insole with good thermal insulation using new materials. We investigated that aerogel/fiber composite can be used as padding materials of shoes by comparing surface shape, moisture regain, water vapor permeability, thermal insulation and compression rate of insole materials tried with nonwoven fabric padding materials and insole sold in market. The results are as follows. Surface shapes were shown that the most appropriate material for sealing aerogel/fiber composite was high density fabric as per size of particle of aerogel. Moisture regain of aerogel/fabric composite was better than nonwoven fabric padding samples. However, when compared to insole sold in market, its moisture regain was worse than those of insole merchandises. Water vapor permeability was higher in material padded with nonwoven fabric than materials padded with aerogel/fiber composite in all three kinds of sealing fabrics. Thermal conductivity of aerogel/fabric composite was lower than nonwoven fabric material regardless of sealing fabrics. Thermal insulation of aerogel/fiber composite was higher than padding material of nonwoven fabric regardless of sealing fabrics. Compression rate of nonwoven (SP1) was higher than that of aerogel/fiber composite (SP2). Compressive elastic recovery rate of SP1 was also higher than that of SP2, which its compression rate and compressive elastic recovery rate were both poor. As the above result, ultra porous aerogel/fiber composite were proved to be material of good thermal insulation with lower thermal conductivity and also compression rate was proved to be low. Therefore, we can say that aerogel/fiber composite have high possibility to be used as insole materials for cold winter shoes requiring good thermal insulation protection.

Effects of processing conditions on physical properties of alginate film (가공조건이 alginate 필름의 물리적성질에 미치는 영향)

  • YOU Byeong-Jin;SHIM Jae-Man
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.5
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    • pp.582-586
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    • 1999
  • The processing conditions for producing and edible alginate film from sea tangle were investigated by measuring water vapor permeability (WVP), tensile properties and colors of film. The alginates were extracted with $3\%$ sodium carbonate ($Na_2CO_3$) solution for 5 hrs, and the alginate films were prepared with extracted sodium alginates, D-gluconic acid lactone, $CaCO_3$ and various plasticizers, As the concentration of alginate in making the film was increased, the WVP and elongation of the film were decreased and the tensile strength was increased. The higher amount of plasticizer showed the higher WVP and elongation, and the order of various plasticizers in increasing the WVP and elongation of the film was glycerol, polyethylene glycol, and sorbitol. The addition of sorbitol in the film showed the highest value (89.57) in lightness of Hunter color system and the film added polyethylene glycol had the highest values (-1,12 and 11.4) in redness and yellowness.

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Permeability and Mechanical Properties of Zein and Gluten-Based Films (Zein과 Gluten 포장지의 수증기투과도와 기계적 특성)

  • Kim, Young-Ho;Kim, Dong-Man;Kim, Kil-Hwan
    • Korean Journal of Food Science and Technology
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    • v.26 no.2
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    • pp.138-140
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    • 1994
  • Permeability and mechanical properties of degradable films prepared with zein and gluten were measured. Tensile strength of zein-based films was ranged from 30.1 MPa to 138.5 MPa and the strength of gluten-based films was $37.1{\sim}98.6\;MPa$. This strength was increased with increase of thickness in both films. Water solubility of zein-based films, 1.3%, was lower than those of the gluten-based films and the cellulose-based films. The range of water vapor permeability was $0.0711{\sim}0.1778\;g\;mm/m^{2}\;hr\;mmHg$ for zein-based films and $0.2134{\sim}0.2972\;g\;mm/m^{2}\;hr\;mmHg$ for gluten-based films. The permeabilty of the films was also increased with thickness.

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Effect of Hydrophilic and Hydrophobic Finishes of Fabrics on the Stratum Corneum Water Content and Comfort Properties (직물의 친수 및 소수화 처리가 피부잔류수분량 및 쾌적감에 미치는 영향)

  • Kahng, Soo Ma;Kim, Eun Ae
    • Journal of the Korean Society of Clothing and Textiles
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    • v.17 no.1
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    • pp.151-161
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    • 1993
  • The purpose of this study was to investigate the effect of hydrophilic finish for polyester (PET) fabric and hydrophobic finish for cotton fabric on the water transport and comfort properties. Polyester fabric was treated with 10% sodium hydroxide solution to impart hydrophilicity. Cotton fabric was sprayed with Scotch-gard$^{(R)}$ water and oil repellent finish to impart hydrophobicity. Porosity, air permeability, contact angle, wickability and water vapor transport rate (WVTR) were measured to determine the water transport properties of fabrics. To compare the comfort properties of treated and untreated fabrics, wear test was performed by putting fabric patches on the upper back: stratum corneum water content (SCWC), subjective wettedness and comfort rating were determined. The results were as follows: (1) The contact angle of water on treated polyester fabric was decreased and that of treated cotton fabric was increased. Also, the wickability of treated polyester fabric was increased and the wickability of cotton fabric was decreased. (2) Although each finish did not change porosity, the water vapor transport rate of treated polyester fabric was increased and that of treated cotton fabric was decreased slightly. (3) The results of stratum corneum water content measurements showed good agreement with the results of the contact angle and the wickability, i.e., the better the liquid water transport properties are, the less the stratum corneum water contents were resulted. (4) The realtionship of subjective wettedness or comfort and stratum corneum water content was independent. Therefore, it was concluded that human perception on the subjective wettedness or the comfort is affected by the skin contact of wet fabric rather than by the stratum corneum water content.

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Geotechnical Characteristics of Prefabricated Vertical Drain System for Contaminated Soil Remediation (오염토양 복원을 위한 연직배수시스템의 지반공학적 특성)

  • Shin, Eunchul;Park, Jeongjun
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.5
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    • pp.5-14
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    • 2007
  • The quantity of noxious wastes generated by the growth in industrialization and population in all over the world and its potential hazards in subsurface environments are becoming increasingly significant. The extraction of the contaminant from the soil and movement of the water are restricted due to the low permeability and adsorption characteristics of the reclaimed soils. Incorporated technique with PVDs have been used for dewatering from fine-grained soils for the purpose of ground improvement by means of soil flushing and soil vapor extraction systems. This paper is to evaluate several key parameters that affected to the performance of the PVDs specifically with regard to: well resistance of PVD, zone of influence, and smear effects. In the feasibility of contaminant remediation was evaluated in pilot-scale laboratory experiments. Well resistance is affected on the vertical discharge capacity of the PVDs under the various vacuum pressures. The discharge capacity increases consistently in areal extents with higher applied vacuum up to a limiting vacuum pressure. The head values for each piezometer at different vacuum pressures show that the largest head loss occurs within 14 cm of the PVD. Air flow rates and head losses were measured for the PVD placed in the model test box and the gas permeability of the silty soils was calculated. Increasing the equivalent diameter results in a decrease in the calculated gas permeability. It is concluded that the gas permeability determined over the 1,500 to 2,000 $cm^3/s$ flow rates are the most accurate values which yields gas permeability of about 3.152 Darcy.

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Changes in Waterproofness and Breathability after Repeated Laundering and Durability of Electrospun Nanofiber Web Laminates (전기방사한 나노섬유 웹 라미네이트 소재의 반복 세탁에 따른 투습방수 성능 변화 및 내구성)

  • Lee, Kyung;Yoon, Bo-Ram;Lee, Seung-Sin
    • Fashion & Textile Research Journal
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    • v.14 no.1
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    • pp.122-129
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    • 2012
  • To develop a waterproof breathable material, we fabricated three kinds of nanofiber web laminates using a massproduced electrospun nanofiber web with different substrates and layer structures. The waterproofness and breathability of nanofiber web laminates were evaluated after repeated launderings and compared with those of conventional waterproof breathable fabrics currently in use, including densely woven fabric, microporous membrane laminated fabric, and coated fabric. The durability of nanofiber web laminates, including adhesion strength, abrasion resistance, tensile strength, and tearing strength, was also assessed and compared with those of conventional waterproof breathable fabrics. The water vapor transmission of nanofiber web laminates increased slightly after repeated launderings, whereas the air permeability somewhat decreased after launderings but still maintained an acceptable level of air permeability. Laundering reduced the resistance to water penetration of nanofiber web laminates, which implies that laminating techniques or substrate materials that could support waterproofness of the laminated structure should be explored. The adhesion strength, abrasion resistance, tensile strength, and tearing strength of nanofiber web laminates were in a range comparable to conventional waterproof breathable materials.

A Study on the Air-Vent System of Complex Layer Applied Poly-Urethane Waterproofing Material and Air-Permeability Buffer Sheet (절연용 통기완충 시트와 폴리우레탄 도막 방수재를 복합 적층한 탈기 시스템에 관한 연구)

  • Oh, Sang-Keun;Park, Bong-Kyu;Ko, Jang-Ryeol;Park, Yoon-Chul;Kim, Su-Ryon
    • Journal of the Korea Institute of Building Construction
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    • v.2 no.1
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    • pp.139-146
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    • 2002
  • This study deals with the characterizing and the application like as insulation materials in the joint part in concrete surface layer and waterproofing sheet especially for roof slabs. Using steel materials and butil-rubber tape to band waterproofing sheet and concrete surface together before this waterproofing system will be applied. It can be expected to both the curability and the watertightness by coating poly-urethane 2 or 3 times with sheet surface. Therefore this waterproofing system can be possible to protect water without the damage when vapor is going out from concrete and without air pockets because of the difference temperature inside and out. This system particularly consists of air bents and elastic waterproofing sheet considering the physical damage while water can cause purely physical damage. This system is one of the most efficient ways of waterproofing system without air pocket.

Subjective Hand and Physical Properties of Tricot based Artificial Suede according to Raising Finish (기모가공 조건에 따른 트리코 기포 인조 스웨이드의 태와 물성)

  • Roh, Eui Kyung;Oh, Kyung Wha
    • Fashion & Textile Research Journal
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    • v.16 no.1
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    • pp.153-159
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    • 2014
  • This study evaluates the changes of the subjective hand, preference, comfort and mechanical properties of tricot based artificial suede made from sea-island type micro fibers according to raising condition. The subjective hand and the preference of raised suede for jacket were rated by the 20's and 30's women experts according to raising cycles. Comfort properties were evaluated by air permeability, water vapor transmission, and thermal transmission. Mechanical properties were measured by the KES-FB system. The subjective hand of artificial suede was categorized into three hand factors: smoothness, warmness and thickness. Smoothness, warmness and thickness perception increased with raising cycles which affected hand preference and luxuriousness perception. The thickness and wale density of suede increased with the number of raising. Suede became more compact and less pliable and less stretchable due to increased fabric thickness; in addition, the surface of suede became smoother and compressive since the surface evenness of suede improved with smaller fiber fineness and an increased amount of naps covered the base fabric. Furthermore, water vapor transmission decreased and thermal insulation increased. The best raising conditions for artificial suede was four cycles in which artificial suede was preferred without changes in physical properties.

Antimicrobial Properties of Wheat Gluten-Chitosan Composite Film in Intermediate-Moisture Food Systems

  • Park, Sang-Kyu;Bae, Dong-Ho
    • Food Science and Biotechnology
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    • v.15 no.1
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    • pp.133-137
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    • 2006
  • Wheat gluten-chitosan composite film (WGCCF) can prevent moisture migration and enhance the antimicrobial properties of gluten in intermediate-moisture foods like sandwiches. To mimic the structure of actual sandwich-type products we developed multi-layer food models, where moisture content and water activity differ. Water activity gradients direct moisture migration and therefore determine product characteristics and product stability. A 10% wheat gluten film-forming solution was mixed with chitosan film-forming solution (0-3%, w/w) and evaporated to generate WGCCF. Addition of 3% chitosan enhanced the mechanical properties of the film composite, lowered its water vapor permeability, and improved its ability to protect against both, Streptococcus faecalis and Escherichia coli, in a 24 hr sandwich test (reduction of 1.3 and 2.7 log cycles, respectively, compared to controls). Best barrier and antimicrobial performance was found for 3% chitosan WGCCF at pH 5.1. Film of this type may find application as barrier film for intermediate-moisture foods.

Preparation of Asymmetric Membranes by Addition of Nonsolvent (비용매 첨가제를 이용한 비대칭막의 제조)

  • Kim, Nowon
    • Membrane Journal
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    • v.25 no.1
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    • pp.32-41
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    • 2015
  • High performance polysulfone microfiltration membranes with a high were successfully prepared by vapor induced phase separation (VIPS) coupled with non-solvent induced phase separation (NIPS) process. Asymmetric Membranes were prepared with PSF/DMF/PVP/PEG/DMSO/water mixed solutions and water/IPA coagulant. PSF, DMF, PVP, PEG, DMSO, water was used as a membrane polymer, a solvent, a hydrophilic polymer additive, a polar protic liquid polymer, a polar aprotic nonsolvent, and a polar protic nonsolvent in the casting solution, respectively. The addition of polar aprotic nonsolvents, and polar protic nonsolvents is a convenient and effective method to control membrane structure. In order to control the morphology of polymeric membranes, the spontaneous emulsification induced by drawing water vapor into the exposed casting solution surface has been used. Control of the internal morphology of polymeric membranes by using mixed coagulation solution such as water and IPA is discussed in the present work. The pure water permeability, pore size distribution, surface hydrophilicity and membrane morphology were investigated. Due to the addition of DMSO to casting solution, the mean pore size increased almost $0.2{\mu}m$ and the water flux increased about 1000-1800 LMH.