• Fibers and Polymers
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• v.7 no.4
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• pp.372-379
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• 2006

The surface topography, tensile properties, and thermal properties of ramie fibers were investigated as reinforcement for fully biodegradable and environmental-friendly 'green' composites. SEM micrographs of a longitudinal and cross sectional view of a single ramie fiber showed a fibrillar structure and rough surface with irregular cross-section, which is considered to provide good interfacial adhesion with polymer resin in composites. An average tensile strength, Young's modulus, and fracture strain of ramie fibers were measured to be 627 MPa, 31.8 GPa, and 2.7 %, respectively. The specific tensile properties of the ramie fiber calculated per unit density were found to be comparable to those of E-glass fibers. Ramie fibers exhibited good thermal stability after aging up to $160^{\circ}C$ with no decrease in tensile strength or Young's modulus. However, at temperatures higher than $160^{\circ}C$ the tensile strength decreased significantly and its fracture behavior was also affected. The moisture content of the ramie fiber was 9.9 %. These properties make ramie fibers suitable as reinforcement for 'green' composites. Also, the green composites can be fabricated at temperatures up to $160^{\circ}C$ without reducing the fiber properties.

• Korean Journal of Human Ecology
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• v.6 no.1
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• pp.27-34
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• 2003

We investigated the bacterial and chemical retting conditions of ramie grown in Hansan. Bacterial retting was done in troughs at a temperature of 30${\pm}$2$^{\circ}C$ for 1, 2, 3, 4, 5, 6 and 10 days. Chemical retting(CR) was done at the different conditions using sodium silicate (Na$_2$SiO$_3$), sodium carbonate(Na$_2$CO$_3$) and sodium hydroxide(NaOH) as alkali solutions. The retting solution was boiled during 1. 2, 4 and 6 hours respectively at the different concentration(0.5, 2.0, 4.0, 6.0. 8.0 %) with decorticated ramie stems submerged in it. The treated ramie was then rinsing with running tap water thoroughly, which was further soaker in 0.5% acetic acid (v/v) solution for three minutes and washed thoroughly with distilled water. Finally ramie was dried for 2 hours in vacuum oven at 100 $^{\circ}C$. To know change of ramie fiber characteristics retted at the different conditions, weight loss, fiber bundle strength were tested and color, texture, luster etc. were also sensually evaluated. The results were as follows. $.$ Weight loss of ramie retted in each alkali solutions were about 10%, 20% and 30% in sodium silicate, sodium carbonate and sodium hydroxide, respectively. $.$ Chemical retting was faster than bacterial retting, but the color of chemically retted ramies were worse than that of bacterially retted ramies. $.$ The combination of bacterial and chemical processing showed some merits. A combination of either 2 or 3 days of bacterial and then chemical retting might provide the best quality ramie. $.$ Ramie fiber became cottonized ramie when retted in 8% NaOH solution for 6-8hours.

• Journal of Adhesion and Interface
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• v.6 no.2
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• pp.13-20
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• 2005

Interfacial shear strength (IFSS) of environmentally friendly natural fiber reinforced polymer composites plays a very important role in controlling the overall mechanical performance. The IFSS of various Ramie and Kenaf fibers/epoxy composites was evaluated using the combination of micromechanical test and nondestructive acoustic emission (AE) to find out optimal conditions for desirable final performance. Dynamic contact angle was measured for Ramie and Kenaf fibers and correlated the wettability properties with interfacial adhesion. Mechanical properties of Ramie and Kenaf fibers were investigated using single-fiber tensile test and analyzed statistically by both uni-and bimodal Weibull distributions. An influence of clamping effect on a real elongation for both Ramie and Kenaf fibers were evaluated as well. Two different microfailure modes, axial debonding and fibril fracture coming from fiber bundles and single fiber composites (SFC) were observed under tension and compression.

• Fibers and Polymers
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• v.7 no.4
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• pp.380-388
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• 2006

Fully biodegradable and environment-friendly green composite specimens were made using ramie fibers and soy protein concentrate (SPC) resin. SPC was used as continuous phase resin in green composites. The SPC resin was plasticized with glycerin. Precuring and curing processes for the resin were optimized to obtain required mechanical properties. Unidirectional green composites were prepared by combining 65% (on weight basis) ramie fibers and SPC resin. The tensile strength and Young's modulus of these composites were significantly higher compared to those of pure SPC resin. Tensile and flexural properties of the composite in the longitudinal direction were moderate and found to be significantly higher than those of three common wood varieties. In the transverse direction, however, their properties were comparable with those of wood specimens. Scanning electron microscope (SEM) micrographs of the tensile fracture surfaces of the green composite indicated good interfacial bonding between ramie fibers and SPC resin. Theoretical values for tensile strength and Young's modulus, calculated using simple rule of mixture were higher than the experimentally obtained values. The main reasons for this discrepancy are loss of fiber alignment, voids and fiber compression due to resin shrinking during curing.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.5
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• pp.891-900
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• 2001

The purpose of this study were to evaluate the physical properties and dyeability of cellulase and alkali(NaOH, KOH) treated ramie/man-made fiber mixture fabrics. The mixture fabrics were plain weave made by rayon and polyester fiber as warp yarn, and ramie as weft yarn. The crease resistance, drape, tensile strength, and water absorbancy were measured for test fabrics. The K/S value of dyed fabrics were calculated using color difference meter. Also colorfastness to washing and sunlight of dyed fabrics were evaluated. The results obtained from this study were as follows: Thickness and weight per unit area of alkali treated two mixture fabrics(rayon/ramie, polyester/ramie) increased compared to those of untreated fabrics, but cellulase treated fabrics did not changed a little. And alkali treated rayon/ramie mixture fabrics showed more change than polyester/ramie mixture fabrics on the thickness and weight. Tensile strength and water absorbancy of cellulase treated fabrics decreased compared to those of untreated, but crease resistance increased. Crease resistance, tensile strength(warp direction), water absorbancy and drape of NaOH treated rayon/ramie mixture fabrics decreased compared to those of untreated, but tensile strength(weft direction) increased. Water absorbancy and drape of NaOH treated polyester/ramie mixture fabrics decreased compared to those of untreated, but crease resistance and tensile strength(weft direction) increased. Tensile strength of KOH treated two mixture fabrics increased compared to that of untreated, but water absorbancy and drape decreased. Total hand of cellulase and alkali treated rayon/ramie mixture fabrics was improved compared to untreated. Dyeability of treated mixture fabrics was increased compared to untreated.

• Journal of Sericultural and Entomological Science
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• v.41 no.3
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• pp.222-227
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• 1999

The weavability and bleaching of ramie/silk mixture fabrics were examined. When silk fiber was used as warp or weft in the mixture fabrics, the weaving properties became higher than that of ramile fabrics. Especially, the highest weavabiliy of mixture fabrics was obtained when used as warp silk fiber. The whiteness of ramie and tussah fiber treated with hydrogen peroxide, bleaching agent. was increased up to about 80% without significant changes of tenacity and elongation. As the increase of bleaching agent and treatment time, the whiteness of mixture fabrics was increased and the yellowness was decreased. Also, as the whiteness of mixture fabrics increased, the drape stiffness in warp direction was decreased but crease recovery was increased.

• Fashion & Textile Research Journal
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• v.13 no.3
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• pp.438-444
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• 2011

Bamboo leaves, as natural dye provide unartificial fresh green, are known for expert property at anti-bacterial, anti-aging, anti-oxidation, skin whitening, moisturizing, peeling of horny, deodorizing and some skin disease like as eczema and inflammation without any allergic response. Also, It is quite common to obtain bamboo leaves from our surrounding but most of them were not in use. On purpose of development the way of recycle with common material to dye, bamboo leaves were used to dye on ramie fiber which is valuable for both of apparel and industrial field and investigated their dyeing property. Using extract from bamboo leaves, dyeing property was examined with dyeability, colorimetric property, light fastness and wash fastness under different conditions by extract density, dyeing time, dyeing method and mordants. As results, dyeing was generally colored in yellowish, K/S Value was shown more higher on hemp fiber than ramie. The most optimum dyeing condition was investigated on pre-mordant treatment, dyeing temperature $60^{\circ}C$, dyeing time 30min and extract density 400%. On the treatment with mordant(Al, Fe, Cu), dyebility on both of hemp and ramie fiber were increased by mordant. Especially with Copper(Cu) as mordant, dyebility was highly increased than any other mordants and dyeings showed in deep color. Also on the fastness test which is the most important to natural dyeing, wash-fastness showed good performance with 4-5 grade but light-fastness was above 4 grade on both of hemp and ramie fiber, lower than wash-fastness overall.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.83-84
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• 2003

The microstructure and tensile properties of ramie treated with NaOH and crosslinked with 1, 2, 3, 4-butanetetracarboxylic acid were characterised. X-ray diffraction and FTIR were used to study the crystalline structure o f the resultant ramie yarns. Results showed that the maximum change in the structure of the modified ramie took place at 16% NaOH, which would completely transform Cellulose I to Cellulose II. Also, the crystallinity index and fibre orientation decreased to the minimum value while the absorption properties were enhanced. The average degree of polymerization of the treated ramie yams slightly decreased after NaOH treatment.

• Fashion & Textile Research Journal
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• v.15 no.3
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• pp.430-436
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• 2013

The purpose of this study investigates the effects of electron beam(EB) irradiation on the chemical and morphological properties of Hansan ramie fiber. Hansan ramie fibers were irradiated with electron beam doses of 0, 1, 3, 5 and 10kGy. The effect of electron beam irradiation on the chemical components of fibers as well as the surface chemical and morphological properties were investigated using chemical component analysis methods based on TAPPI standards, XPS, and SEM. The results indicate that the surface layers can be removed under suitable EB irradiation doses. Alcohol-benzene extraction and lignin content increases gradually with an increase in EB irradiation and reaching a maximum at an EB dose of 3kGy, and decreases at 10kGy. The surface chemical changes measured by XPS corresponded to the chemical composition analysis results. The C1 peak and the O/C ratio decreased with the removal of the multi-layer and primary layer by EB irradiation. The SEM images show the inter-fibrillar structure etched by EB irradiation up to 5kGy. At 10kGy, the surface structure of the ramie fiber shows highly aligned and distinctive striations in a longitudinal direction. The removal of these exterior layers of the fiber was confirmed by changes in surface morphology as observed in SEM images.

• 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.