• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.92-95
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• 2004

Interfacial shear strength (IFSS) of environmentally- friend natural fiber reinforced polymer composites playa very important role in controlling the overall mechanical properties. In this work the IFSS of Ramie and Kenaf fibers/epoxy systems were evaluated using the combination of micromechanical technique, microdroplet test to find out an optimal condition in accordance with final purpose by comparing to each other. Clamping effect on fiber elongation was determined as well. In addition, the mechanical properties of the natural fibers were investigated using single fiber tensile test and analyzed statistically by both uni- and bimodal Weibull distributions. Microfailure modes of different natural fiber structures were observed using optical microscope.

• Macromolecular Research
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• v.16 no.5
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• pp.411-417
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• 2008

The surfaces of henequen fibers, which can be obtained from the leaves of agave plants, were treated with two different media, tap water and sodium hydroxide, that underwent both soaking and ultrasonic methods for the fiber surface treatment. Various biocomposites were fabricated with untreated and treated, chopped henequen fibers and polypropylene using a compression molding method. The result is discussed in terms of interfacial shear strength, flexural properties, dynamic mechanical properties, and fracture surface observations of the biocomposites. The soaking (static method) and ultrasonic (dynamic method) treatments with tap water and sodium hydroxide at different concentrations and treatment times significantly influenced the interfacial, flexural and dynamic mechanical properties of henequen/polypropylene biocomposites. The alkali treatment was more effective than the water treatment in improving the interfacial and mechanical properties of randomly oriented, chopped henequen/PP bio-composites. In addition, the application of the ultrasonic method to each treatment was relatively more effective in increasing the properties than the soaking method, depending on the treatment medium and condition. The greatest improvement in the properties studied was achieved by ultrasonic alkalization of natural fibers, which was in agreement with the other results of interfacial shear strength, flexural strength and modulus, storage modulus, and fracture surfaces.

• Advances in concrete construction
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• v.13 no.2
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• pp.133-152
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• 2022

Ecological issues such as natural resource reduction and enormous waste disposals are increasingly leading in developing civilization toward sustainable construction. The two primary environmental issues are the depletion of natural resources and the disposal of trash in open landfills. Waste steel fiber (WSF) was investigated for usage as a cement-based concrete (CBC) constituent in this research. Recycling waste fibers both makes cement composites more long and cost-effective, also aids in pollution reduction. The objective of this study is to analyze the impacts of waste fiber on the fresh and mechanical features of concrete using recycled additives. A comparative research on the durability and mechanical qualities of fiber-reinforced concrete (FRC) constructed with natural aggregates was conducted for this aim. The obstacles to successful WSF recycling methods application in the building industry have been investigated, resulting that CBCs with these fibers make an economic and long lasting choice to deal with waste materials. The workability of fiber enhanced concrete was found to be comparable to that of normal concrete. Fibers have a considerable impact on the splitting tensile strength, flexural and compressive strength of recycled concrete. Fiber may enhance the water permeability. When the WSF content is 0.6 kg/m3, the water absorption is nearly half. Fibers would have no effect on its permeability.

• Journal of Adhesion and Interface
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• v.7 no.2
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• pp.1-11
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• 2006

Interfacial evaluation of the untreated and treated Jute and Hemp fibers reinforced different matrix polypropylene-maleic anhydride polypropylene copolymer (PP-MAPP) composites were investigated by micromechanical technique and dynamic contact angle measurement. For the statistical tensile strength of Jute and Hemp fibers, bimodal Weibull distribution was fitted better than the unimodal distribution. The acid-base parameter on the interfacial shear strength (IFSS) of the natural fiber composites was characterized by calculating the work adhesion, $W_a$. The effect of alkaline, silane coupling agent on natural fibers were obtained with changing MAPP content in PP-MAPP matrices. Alkaline treated fibers made the surface energy to be higher due to removing the weak boundary layers and thus increasing surface area, whereas surface energy of silane treated Jute and Hemp fibers decreased due to blocked high energy sites. MAPP in the PP-MAPP matrix caused the surface energy to increase due to introduced acid-base sites. Microfailure modes of two natural fiber composites were observed clearly differently due to different tensile strength of natural fibers.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.165-171
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• 2015

Dust samples collected from air in metropolitan areas of Busan and Ulsan were analyzed by phase contrast microscopy, phase contrast dispersion microscopy and SEM. Asbestos concentration in dust samples was lower than detection limit. Many fibrous materials were observed in dust samples, but most of them were organic fibers. Inorganic fibers such as rock fiber, ceramic fiber and gypsum were contained in the samples and non-fibrous minerals such as quartz, calcite and feldspar were also occasionally observed. Domestic law requires that asbestos in air dust is mainly analyzed by phase contrast microscopy. From this study, however, precise analysis of asbestos was almost impossible by this method only. As indicated in JIS method of Japan, therefore, count and identification of asbestos were more efficient by dispersion staining method after removing organic materials in samples by low temperature incinerator.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.29-35
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• 2013

The objective of the current study is to evaluate the effects depending on the types of reinforcing fibers being influential in view of mechanical properties and impact resistance of hybrid fiber reinforced concrete (HFRC) for applications to precast concrete structure. Hybrid fibers applied therefor were three types such as PP/MSF (polypropylene fiber+macro synthetic fiber), PVA/MAF (polyvinyl alcohol fiber+MSF) and JUTE/MSF (natural jute fiber+MSF), where the volume fraction of PP, PVA and natural jute was applied with 0.2 %, respectively, while based on 0.05 % volume fraction of MSF. The HFRC was tested for slump, compressive strength, flexural strength and impact resistance. The test result demonstrated that mixture of such hybrid fibers improve compressive strength, flexural strength and impact resistance of concrete. Moreover, it was found that HFRCs to which hydrophilic fibers, i.e. PVA/MSF and JUTE/MSF, were mixed show more improved features that HFRC to which non-hydrophilic fiber, i.e. PP/MSF was mixed. Meanwhile, the finding that PVA/MSF HFRC exhibited better performance than JUTE/MSF HFRC was attributed from the former having higher aspect ratio than that of the latter.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.1
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• pp.16-23
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• 2012

Use of security papers for monetary papers, gift certificates, and lottery tickets increases every year. As the use of security papers increase, there are more possibility of counterfeits. In this study, we used unique fibers from the sea to increase the difficulties against counterfeiting. The red algae fibers give opacity as much as calcium carbonates, and have unique shape in length ($500{\sim}900\;{\mu}m$) and width ($1{\sim}4\;{\mu}m$) to be discerned from other natural fibers such as wood and cotton fibers. We mixed red algae fibers to wood fibers in a series of fixed ratios to make single and multiply papers for making security papers. Paper with dyed red algae fibers were also used. Paper made without fillers gave enough opacity for printing when red algae fibers were used more than 20% of the fiber furnish. Those properties may allow red algae fibers to be a potential candidate for fiber raw materials of security paper.

• The Research Journal of the Costume Culture
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• v.25 no.5
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• pp.648-655
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• 2017

This study measured dyeing properties under different dyeing conditions and levels of antimicrobial activity when man-made fibers are dyed with gallnut, including rayon, tencel, tencel blended fabric, soybean fiber, and nylon non-mordanted. The dye up-take (K/S), color ($L^*a^*b^*$), and color differences (${\Delta}E$) were measured with a colorimeter, and the number of bacteria present in the dyed fabrics were determined using Staphylococcus aureus and Klebsiella pneumonia as strains. The results are as follows: First, the optimal dyeing conditions for man-made fibers dyed with gallnut are 60 minutes of dyeing time and a $80^{\circ}C$ dyeing temperature. Second, gallnut dye is most effective on soybean fiber and then, in descending order of effectiveness, on nylon, rayon, tencel, and tencel blended fabric. This means that dyeing properties of nitrogen containing fibers are excellent when using gallnut. Third, all man-made fibers are dyed brown with gallnut. This implies dyeing possibility of man-made fibers about gallnut dye, so development and supply of natural dyed goods of man-made fibers can be increased. Fourth, in all man-made fibers dyed with gallnut extract, both Staphylococcus aureus and Klebsiella pneumonia show 99.9% reduction ratios of fungistasis, which indicate antimicrobial activity. Therefore, safe, functional, man-made materials can be developed to relieve symptoms from and treat patients with skin ailments.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.229-230
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• 2009

Recently the demand for wool has been gradually decreasing due to global warming, oil depletion, Coolbiz campaign to reduce CO2 emission, and preference for business casual wear, while the price for wool materials has been constantly increasing. Wool, characterized by the natural touch and unique sensibility, is considered as one of the best natural materials, including silk. For wool, currently Korea almost depends on import from foreign countries. Therefore, 100% wool products cannot be competitive in terms of pricing and current trend. To secure sustaining competitiveness in the fiber market, it is required not only to develop new wool materials that enable expression of new sensibility that cannot be expressed by conventional wool fibers, but also to pursue differentiation of fundamental sensibility and functionality by highlighting advantages for wool as a natural fiber but by reducing its disadvantages through dominant conjugation with synthetic fibers. This study attempted to improve the technology of differentiating wool-like synthetic fibers such as polyester and combine technology with sensibility through mixing with wool materials. It also aimed to develop wool-like stretch materials and pre-treating and yarn dyeing technologies that enable fabrics to main natural wool-like touch and stretch, and ultimately to develop wool mixed fabrics that have new sensibility and functionality.

• Journal of Fashion Business
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• v.7 no.2
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• pp.156-164
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• 2003

It has been known that the natural colorants exhibit good dye-uptake toward cotton, silk, and wool fibers, while they do poorly toward synthetic fibers. This study utilizes the chitosan treatment in order to improve the dye-uptake for the natural fibers and to enable the synthetic fibers, whose dye-uptake levels are low, show better affinity toward the natural colorants. Since chitosan has $-NH_2$ group and -OH group in the structure, the dyeability of the fabric will be improved when the fabric is treated with the chitosan. Cotton fabric as one of the natural fiber fabrics and nylon fabric as one of the synthetic fiber fabrics were selected for this study. 1. In case of cotton fabric, the chiosan treatment takes effect for the Caesalpinia sappan and cochineal, resulting in remarkable ${\Delta}E$ increase after dyeing. Chitosan helps in developing dark shade by increasing the uptake of the Caesalpinia sappan and cochineal. It does not, however, participate in the developing of the specific color as does a metallic mordant. 2. In case of dyeing cotton fabric with Gardenia jasminoides, the effect of the treatment with mordant and chitosan is not very pronounced. It is thought that the Gardenia jasminoides uptake is accomplished in a direct manner in the cellulose chains without the aid of mordant. 3. Air-permeability is decreased when the non-mordanted and non-chitosan treated cotton fabric is dyed with Caesalpinia sappan, cochineal, and Gardenia jasminoides. 4. In case of nylon fabric, premordanting and chitosan treatments are not highly effective in promoting the dye-uptake.