• Fibers and Polymers
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• v.2 no.1
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• pp.144-147
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• 2001

The HVI properites and Mantis single fiber tensile properties were analyzed to evaluate the relationship between fiber and bundle tensile properties. For this study, a new method has been developed for estimating the modulus and toughness of cotton fiber bundles directly from the HVI tenacity-elongation curves. The single fiber tensile properties were shown to be translated well into the bundle tensile properties. The single fiber breaking elongation was found to be the most significant contributing factor to bundle tensile properties. The bundle breaking elongation and toughness were shown to increase as the single fiber breaking elongation increased. The bundle modulus increased as the single fiber breaking elongation and/or standard deviation of single fiber breaking elongation decreased.

• Journal of the Korean Wood Science and Technology
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• v.50 no.6
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• pp.392-403
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• 2022

Currently, composite board manufacturing using natural fibers has the potential to expand owing to environmental awareness. To produce a composite board, treatment is required to improve the mechanical and physical properties of the natural fibers. In this study, sodium chloride (NaCl) was used for the chemical treatment. However, studies on chemical treatments using NaCl are limited. This study aimed to investigate the characteristics of kenaf fibers after NaCl treatment. The NaCl treatment concentrations were 1, 3, and 5 wt.% at room temperature, with soaking durations of 1, 2, and 3 h. The tensile strength, strain, and Young's modulus were measured to evaluate the mechanical properties of the fibers. The fiber bundle diameter, weight change owing to treatment, and contact angle were determined to analyze the effect of NaCl treatment. The kenaf fiber bundle treated with 5 wt.% NaCl for 3 h exhibited the highest tensile strength, Young's modulus, reduction in fiber bundle diameter, weight change, and decrease in contact angle compared to those of untreated fiber bundles. The tensile properties of the fiber bundle exhibited a tendency to decrease with increasing fiber bundle diameter. Increasing the soaking duration from 1 to 2 h did not result in a significant decrease in the fiber bundle diameter or an increase in tensile strength. However, a further increase in the soaking duration from 2 to 3 h resulted in a considerable decrease in the fiber bundle diameter and an increase in the tensile strength.

• Fibers and Polymers
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• v.6 no.1
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• pp.42-48
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• 2005

The effects of opening, carding, and repeated drawings on single fiber and bundle cotton characteristics were stud­ied by employing $Mantis^{\circledR}$, $AFIS^{\circledR}$ and HVI Testers. Some of the significant changes in single fiber properties were found to be due to process parameters as well as the changes in the fiber crimps, parallelness of fibers within HVI beards, and the actual changes in the tensile properties of the fibers. The study showed that the HVI test data taken just prior to spinning had the highest correlation with the yam tensile properties. Based on the study results, we point out the potential of HVI for future quality and process control in spinning by recommending a set of expanded HVI output that is more scientific and compre­hensive for the future control needs.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.7
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• pp.862-871
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• 2003

Kenaf has been estimated as an economic and environmentally compatible crop. This study purposed to enlarge the use of kenaf as textile materials and to develope high value-added textile fibers. Kenaf has been cultivated successfully and grown fast in Jeju. The height of kenaf stalks was about 220cm at 105 DAP and 400cm at 150 DAP, After harvesting at 105 DAP and seperating the basts from harvested kenaf stalks, decorticated kenaf basts were rotted in water at 15~$25^{\circ}C$ for biological rotting and were treated with 1%, 4% and 7% NaOH at 9$0^{\circ}C$ for chemical retting. The properties of extracted fibers were compared: such as fiber diameter. Transversal and longitudinal views, colors, crystallinities, strengths and elongations etc. The diameter of kenaf bast fibers was 15~25 ${\mu}{\textrm}{m}$. Biologically rotted kenaf bast fibers had well developed lumens which were diminished after chemical retting. The degree of crystallinities of biologically rotted kenaf bast fiber was about 92~96% showed higher than those of chemically rotting. The biologically rotted fibers were bright and had creamy color. Yelloweness increased at chemically rotted fibers. Fiber bundle strengths were from maximum 98076.9 (gf/g) to minimum 63749.5 (gf/g). Fiber bundle strengths of biologically rotted kenaf fibers appeared greater than those of chemically rotted fibers. Alkali treatments of chemical rotting could make strength lower and elongation higher. Rotting method might be one of the most importance factors affecting to final fiber properties.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.787-788
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• 2008

• Honam Mathematical Journal
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• v.5 no.1
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• pp.121-127
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• 1983

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.168-175
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• 2016

The surface of glass fiber bundle was modified with functionalized silanes and phenolic resin to improve the tensile strength as well as the adhesion of glass fiber to matrix phenolic resin. The surface modification of reinforcing glass fiber can play a significant role in controlling whole composite characteristics. We applied surface modification of glass fiber with two different functionalized silanes, such as glycidyltrimethoxysilane(G-silane) and aminopropyltriethoxysilane (A-silane), and phenol formaldehyde(PF) resin in one pot or separated process under different coating compositions and temperatures. Thermal treatment temperature is very important factor to improve the mechanical properties of modified glass fiber. Modified glass fiber bundle treated at $170^{\circ}C$ showed the highest tensile strength of $10.05g_f/D$. Surface analyses by scanning electron microscope(SEM) and FT-IR spectroscopy were used to characterize the surface coatings on glass fiber bundles. Mechanical property changes as functions of treatment conditions and coupling agent types were also explained.

• Carbon letters
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• v.9 no.4
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• pp.316-323
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• 2008

The factors that influence ablation resistance in fiber composites are properties of the reinforced fiber and matrix, plugging quantity of fiber, geometrical arrangement, crack, pore size, and their distributions. To examine ablation resistance according to distribution of crack and pore size that exist in carbon/carbon composites, this study produced various sizes of unit cells of preforms. They were densified using high pressure impregnation and carbonization process. Reinforced fiber is PAN based carbon fiber and composites were heat-treated up to $2800^{\circ}C$. The finally acquired density of carbon/carbon composites reached more than $1.932\;g/cm^3$. The ablation test was performed by a solid propellant rocket engine. The erosion rate of samples is below 0.0286 mm/s. In conclusion, in terms of ablation properties, the higher degree of graphitization is, the more fibers that are arranged vertically to the direction of combustion flame are, and the less interface between reinforced fiber bundle and matrix is, the better ablation resistance is shown.

• Carbon letters
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• v.9 no.1
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• pp.28-34
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• 2008

Multidirectional reinforcement is aimed primarily at overcoming interlaminar weakness, hence a major interest lies in the mechanical properties of multidirectional carbon/carbon composites. Mechanical properties depend on the type of carbon fiber, the size of the fiber bundle, the spacing of the bundles, the angles of the bundles relative to the axes of the block, and matrix formation. In the present studies, PAN based carbon fiber preforms manufactured different size of unit cell have been prepared. Densification of these used high pressure infiltration and carbonization technique with coal tar pitch as matrix precursor was carried out. Scanning electron microscopy has been used to study the fracture behavior of composites. The size of unit cell of the preforms has considerably affected on the flexural properties as well as microstructure of the carbon/carbon composites.

• Advanced Composite Materials
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• v.16 no.4
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• pp.315-334
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• 2007

In the present study, chopped henequen natural fibers without and with surface modification by electron beam (E-beam) treatment were incorporated into a polypropylene matrix. Prior to composite fabrication, a bundle of raw henequen fibers were treated at various E-beam intensities from 10 kGy to 500 kGy. The effect of E-beam intensity on the interfacial, mechanical and thermal properties of randomly oriented henequen/polypropylene composites with the fiber contents of 40 vol% was investigated focusing on the interfacial shear strength, flexural and tensile properties, dynamic mechanical properties, thermal stability, and fracture behavior. Each characteristic of the material strongly depended on the E-beam intensity irradiated, showing an increasing or decreasing effect. The present study demonstrates that henequen fiber surfaces can be modified successfully with an appropriate dosage of electron beam and use of a low E-beam intensity of 10 kGy results in the improvement of the interfacial properties, flexural properties, tensile properties, dynamic mechanical properties and thermal stability of henequen/polypropylene composites.