• Elastomers and Composites
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• 제46권3호
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• pp.186-194
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• 2011

셀룰로오스계 천연섬유인 kenaf를 천연고무와 함께 균일하게 배합한 후 압축성형 방법을 사용하여 천연섬유/천연고무 복합재료를 제조하였으며, 이들의 가황거동, 경도, 인장특성, 인열강도 및 정적, 동적 특성에 미치는 kenaf 섬유함량의 영향을 조사하였다. 복합재료를 구성하는 천연섬유의 함량은 천연고무 및 배합제 대비 0, 5, 10, 15, 20 phr이었다. 실험결과 천연고무의 여러 가지 특성이 kenaf 섬유의 함량에 의존한다는 것을 나타내었다. Kenaf 섬유함량이 증가함에 따라 천연고무의 가황에 요구되는 토크는 높아진 반면 가황시간은 감소되었다. Kenaf/천연고무 복합재료의 경도, 인장탄성률과 인열강도는 섬유함량이 증가할수록 점차적으로 증가한 반면, 인장강도와 파단신장률 은 감소하는 경향을 보여주었다. 또한 kenaf 섬유함량이 증가함에 따라 천연고무의 정적 특성보다는 동적 특성의 변화가 더욱 크게 나타났다. 고무에 가해지는 에너지의 감쇄 또는 흡수와 밀접한 관계가 있는 손실인자도 섬유함량에 비례하여 증가하였다.

• 접착 및 계면
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• 제9권4호
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• pp.1-11
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• 2008

본 연구에서는 바이오복합재료 성형 전에 침지방법과 초음파방법을 이용하여 수산화나트륨 용액으로 kenaf 섬유를 처리하였다. Kenaf/poly(lactic acid)의 kenaf-PLA 계면접착력과 기계적, 열적 특성에 미치는 알칼리처리의 영향을 계면전단강도, 굴곡강도, 동역학적 열특성 및 열안정성을 조사하였으며, kenaf 섬유와 복합재료 파단면을 관찰하였다. 그 결과 Kenaf 섬유표면을 처리하기 위한 침지방법과 초음파방법 모두 바이오복합재료의 섬유-매트릭스 접착과 기계적 특성을 증가시키는 역할을 하는 것으로 조사되었다. 바이오복합재료의 특성은 섬유표면 처리방법뿐만 아니라 알칼리 농도 및 처리시간에도 의존하였다.

• 한국의류학회지
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• 제34권11호
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• pp.1889-1899
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• 2010

This study examines the preparation and characterization of Kenaf/Starch bio-composites used as filler and a matrix. Kenaf was cultivated in Chung-ju in Korea, and the Kenaf/Starch bio-composites were prepared under various conditions of kenaf fiber length (1-5 centimeters); the content of Kenaf fiber was 10%, 20%, 30%, and 40%, and the number of composite layers (one-four). Depending on the formation conditions of Kenaf/Starch composites, the physical properties such as tensile strength, elongation, and the young modulus of the Kenaf/Starch composites were measured. In addition, we measured the SEM cross-section images in order to investigate the interfacial adhesion properties of fractured surfaces. As a result, the tensile strength and elongation of the Kenaf/Starch composites were highest in the molding conditions of a hot press at $120^{\circ}C$, 3000PSI of pressure, and for 30 minute periods. The result of measuring the physical properties of the composites manufactured by varying the content of Kenaf fiber when the content of Kenaf fiber was 30% as well the physical properties of the Kenaf/Starch composite was found desirable. It was found that the physical properties improved with more overlapped layers in the composites manufactured by varying the number of overlapped layers. Through the measuring of the SEM cross-section images, we found that the interfacial adhesion state between the filler and matrix of Kenaf/Starch composite greatly affects the physical properties.

• 한국의류학회지
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• 제28권9_10호
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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.

• 방사선산업학회지
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• 제8권1호
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• pp.53-57
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• 2014

The kenaf is quickly developing as a renewable resource. Kenaf can be grown under a wide range of weather conditions. Modification of kenaf fiber by graft polymerization provides a significant route to alter the chemical properties, including surface hydrophilicity or hydrophobicity. In this study, kenaf fiber surfaces were grafted with acrylic acid as a hydrophilic group using electron beam irradiation. The grafting rate increased with an increase in grafting time. The FT-IR results confirmed that acrylic acid was successfully grafted onto the kenaf fibers. The wettability of the kenaf fiber was increased, accompanied by acylic acid grafting on the fiber surface. According to the permeability test result, it was found that acrylic acid grafted kenaf fiber reinforced cement composite was more reduced than non-grafted kenaf fiber reinforced cement composite.

• 펄프종이기술
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• 제39권4호
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• pp.45-52
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• 2007

Whole, bast and core fibers of kenaf cultivar Tainung-2 were pulped under different pulping methods, thermomechanical and kraft pulping methods. The physical and optical properties of kenaf TMP(thermomechanical pulp) and KP(kraft pulp) handsheets were investigated and the results from the study are summarized as follows: Yields of TMP and KP were $77{\sim}87%\;and\;43{\sim}52%$, respectively. There was no significant change in apparent density between kenaf KP and USKP(unbleached softwood kraft pulp) but TMP showed a little lower apparent density. Bast pulp had the lowest apparent density regardless of pulping methods. Tensile strength of kenaf KP was higher than that of TMP but similar to that of USKP. Both TMP and KP handsheets of bast fraction showed the highest tear strengths among whole, bast, and core fractions. Core fraction showed the lowest tear strengths under different pulping methods. In general burst strength of kenaf pulp under different pulping methods was lower than that of USKP, and kenaf pulp had better stiffness than USKP. Brightness of kenaf KP and TMP was higher than that of USKP. There was no significant variation in opacity between kenaf pulp and USKP even though kenaf pulp showed a little lower opacity. The main difference in paper quality between the core fiber and bast fiber is derived from the fact that bast fiber is long and thin, whereas core fiber is short and thick.

• 한국의류학회지
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• 제27권7호
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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.

• 한국의류학회지
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• 제31권8호
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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.

• 기술사
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• 제10권3호
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• pp.17-26
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• 1977

In order to obtain the most practical and economically efficient method for refining of kenaf fiber and the production possibility of bag dproucts by using kenaf, Various chemicals and conditions of treatment for refining of kenaf bark were examined. Refining by the retting method was found much beneficial in quality of fiber and in processing cost than the chemical mettled. Bag products by using kenaf bark has good quality , and for practical use, Even if the production cost is slightly more expensive than jute bag, it could be reduced by planned mass production.

• 한국의류학회지
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• 제27권9_10호
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• pp.1144-1152
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• 2003

Kenaf has been cultivated in Jeju Island. After being harvested at 105 DAP(day after planting) and separated from kenaf stalks , decorticated kenaf basts were treated with different concentration/temperature/time combinations in order to do chemical rotting. The following fiber properties were compared; rotting effects, colors, crystallinity, molecular structures, dyeabilities, and non-cellulose contents such as pectins, lignins, & hemicellulose. The best results of chemical rotting were obtained from the specimens treated with low concentration/ low temperature/short time. Their colors were bright yellow. The lumens of specimens diminished with the affect of NaOH. The structures of chemically rotted kenaf fibers were cellulose 1. The degree of crystallinity of chemically retted kenaf fibers were very high. Non-cellulose content, especially hemicellulose, was low in the specimens treated with the high NaOH concentration. Dyeabilities of kenaf fibers were higher among the specimens without the non-cellulose content than those with the non-cellulose content.