• 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.

• Polymer(Korea)
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• v.37 no.5
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• pp.613-617
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• 2013

The effects of nano size kenaf cellulose fiber on mechanical property of polypropylene (PP) composite were investigated. The addition of nano-kenaf in place of natural kenaf showed higher tensile strength, flexural strength, impact strength, and heat deflection temperature compared to the natural kenaf filled PP composite, while it shows lower melt flow index, elongation%, and flexural modulus. These seemed to be due to the increased surface area of nano-kenaf fiber contacting PP matrix and reduced impurities such as volatile extractives on the fiber surface.

• Macromolecular Research
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• v.16 no.3
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• pp.253-260
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• 2008

Environmentally friendly biocomposites were made using plant-based natural fibers, such as henequen and kenaf. The natural fiber reinforced polypropylene (PP) and unsaturated polyester (UP) biocomposites were examined in terms of the reinforcing effect of natural fibers on thermoplastic and thermosetting polymers. Kenaf (KE) and henequen (HQ) fibers were treated with an electron beam (EB) of 10 and 200 kGy doses, respectively, or with a 5 wt% NaOH solution. Four types of biocomposites (KE/PP, HQ/PP, KE/UP and HQ/UP) were fabricated by compression molding and each biocomposite was characterized by dynamic mechanical analysis and thermogravimetric analysis. The kenaf fiber had the larger reinforcing effect on the dynamic mechanical properties of both PP and UP biocomposites than the henequen fiber. The highest storage modulus was obtained from the biocomposite with the combination of UP matrix and 200 kGy EB treated kenaf fibers.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.910
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• pp.1282-1291
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• 2004

Kenaf was cultivated and harvested in large quantity in Cheju Island and Chinju, Kyungsangnamdo. It was chemically rotted with 3% NaOH for 60 minutes at 100$^{\circ}C$, neutralized using 1% acetic acid, washed and dried, and obtained 40kg of dry kenaf fiber. Kenaf 15/rayon 85, flax 15/rayon 85, and rayon 100% yam was spun and the physical characteristics were measured. Plain weave and twill weave fabrics were made using each of the above yarns as the filling yam. Cotton 100% yam was used as the warp yam in all fabrics. Kenaf/rayon blend yarns were higher in tenacity and elongation, lower in yam uniformity, higher in the number of nep than the flax/rayon blended yams. Kenaf/rayon blend fabric had higher tenacity and elongation compared to the flax/rayon blend fabric Kenaf/rayon blend fabric was most stiff in both plain weave and twill weave fabrics whereas drape characteristics was dependent upon the fabric structure of the kenaf/rayon blend and flax/rayon blend. There were little differences between the kenaf/rayon blend fabric and the flax/rayon blend fabric in the Kawabata physical measurements and the PHVs. The only drawback of kenaf fiber was it's surface roughness and it is expected that it can be improved by enzyme retting and mechanical bundle separation.

• Journal of Radiation Industry
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• v.8 no.1
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• pp.49-52
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• 2014

Kenaf fibers have excellent properties and possess the potential to be outstanding reinforcing fillers in cement. The grafting of poly(ethylene glycol) methacrylate (PEGMA) to the kenaf fibers is important in improving the compatibility between the fibers and the cement. PEGMA was grafted onto kenaf fibers using gamma-ray radiation. The radiation dose ranged from 20 to 60 kGy, and the dose rate was $10kGy\;h^{-1}$. The degree of grafting increased with increased radiation doses. FT-IR analysis revealed an increase in PEGMA content after gamma-ray radiation induced grafting, further evincing the attachment of PEGMA to the kenaf fibers. The mechanical properties of the gamma-ray grafted kenaf fiber/cement composites were superior to those of the ungrafted kenaf fiber/cement specimens.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.19-25
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• 2014

The purpose of this study is to establish experimentally the mechanical properties of fiber reinforced concrete using kenaf dosages and propose the usable method of kenaf fiber in the concrete industry as natural fiber materials. Kenaf fiber help make the concrete strength including tensile and flexural stronger, more resistant to plastic and drying shrinkage, less amount of carbon dioxide because of having a rough surface and excellent tensile strength of fiber and improving the concrete's corrosion resistance. It is to select the kenaf dosages of 4 cases (0, 0.3, 0.6 and $0.9kg/m^3$ and perform various tests including slump, air content, plastic and drying shrinkage, flexural and tensile strength for fiber reinforced concrete. The results of this study are as follows : In case of increasing kenaf fiber dosages, show the slump decrease and air content increase, also take effect results for increasing concrete strength including flexural and tensile, decreasing plastic and drying shrinkage. therefore, considered test results and cost, the optimum dosages of kenaf fiber is proposed about $0.6kg/m^3$ and need to study on the site application considering concrete quality and another compared tests.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.8
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• pp.982-990
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• 2011

Kenaf fiber can be obtained by decortications of the kenaf plant stem. The properties of the kenaf fiber treated by alkali (NaOH) were investigated by spectrocolorimeter, SEM, X-ray diffractometer, FT-IR and TGA. The kenaf fibers treated by alkali became darker and their Munsell color values changed from Y (yellow) to YR (yellowred) according to an increased NaOH concentration. SEM observation of the kenaf fibers showed that their crimps were developed and their surfaces were cleaned by the removal of protruding ends and impurities after alkali treatments. In the x-ray diffraction analysis, the structures of the fibers were found in the form of cellulose I when treated with a 0-16% alkali concentration and cellulose II when treated with over 20%. It was also confirmed that the crystallinity was lowered according to an increased NaOH concentration. The change of fiber compositions was investigated in FT-IR analysis. Strong band of $1,738cm^{-1}$ and asymmetrical stretching strong bands of $1,630-1,600cm^{-1}$ in spectrum (which represent pectin) were not found in the samples because the pectin was removed by the alkali treatment. Weak bands of $1,728-1,730cm^{-1}$ and peaks of $1,245-1,259cm^{-1}$ (which represent hemicellulose) and peaks of $1,592cm^{-1}$, $1,504cm^{-1}$, $1,462cm^{-1}$ and $1,429cm^{-1}$ (which are related to lignin) were not found or reduced in the samples treated with a concentration over 20%. TGA indicated that the kenaf fiber had the better hydrophilic properties by alkali treatment. The higher Tmax in TGA and the higher thermal stability when treated by alkali with the higher concentration. The fibers treated with an alkali concentration over 30% did not show any changes in Tmax.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.2
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• pp.47-54
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• 2009

Anatomical characteristics of kenaf were investigated in transverse, radial and tangential direction by optical and scanning electron micrograph. Kenaf was made up of bast fibers, wood fibers, vessels and parenchyma cells. Bast fibers were long slender cells with different types of pits. The shape of wood fibers were in various ways and pointed at the ends. The pits were observed on the surface of bast fibers. Kenafs were diffuse and radial porous. and composed of solitary pores and two or three radial pore multiples. Various types of vessels were observed. The pits showed alternate pitting and larger diameter than other cells. Parenchyma cells were rectangular or square with different shapes of pith parenchyma cells compared to conventional types of parenchyma cells in wood. The number of pith on the surfaces were small.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.7 s.144
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• pp.938-947
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• 2005

Kenaf basts were double retted by using water and enzyme. The best conditions were enzyme concentration $0.125\%$ and 1 day treatment at $50^{\circ}C$, 4 days treatment at $20^{\circ}C$. It was showed that the double rotting could be more economical and eco-friendly than just water rotting or enzyme rotting. Kenaf fibers have been cottonized by removing lignin and hemicellulose partially. In order to cottonize kenaf fiber, lignin of kenaf fibers were removed by sodium chlorite and then hemicellulose of kenaf fibers were removed by sodium hydroxide. The cottonizing phenomenon of kenaf fibers were was confirmed in transversal and longitudinal photograph of SEM. The tensile strength and crystallinity of cottonized fiber were investigated. The tensile strength and crystallinity were lower as the lignin and hemicellulose of kenaf fibers were less.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.8
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• pp.1286-1296
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• 2007

Hanji, the korean traditional papers were mostly made from mulberry paper. But the production and demand of hanji have decreased rapidly because mulberry paper yields were insufficient and handworked hanji procedures were complicated. Recently, the researches on hanji were carried out to improve the properties of hanji. Kenaf fibers have been interested as a substitute resource of mulberry paper for hanji production. In this research, Kenai pulps were manufactured with removal methods of lignin or hemicellulose from kenaf fibers and paper mulberry pulps with traditional alkali methods. Kenaf papers, paper mulberry, and kenaf/paper mulberry mixed papers were manufactured with their pulps. The crystallinity, fiber length, color of the pulps and tensile strength, tear strength, water absorption of the papers were investigated. The results were as follow: The removal rates of lignin of chemical retted kenaf fibers with sodium chlorite reaction for 40 minutes were 70% and were higher than 40% of double retted fibers. Paper mulberry pulps has less lignin and hemicellulose than kenaf differently. The crystallinity of paper mulberry pulps were very low with 60%, but kenaf pulps were 90%. The chemical retted CR-40-1 pulps were similar with paper mulberry pulps on fiber length & fibrilation of fibers. Tensile strength of paper mulberry were higher than kenaf papers because of fibrilation of paper mulberry, but tear strength were lower. Tensile strength and tear strength were improved on kenaf/paper mulberry 30/70 mixed papers.