• Advanced Composite Materials
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• 제18권3호
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• pp.197-208
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• 2009

Changes occurring in jute and coir fiber composites with 2-8% concentration of a NaOH treatment for 24 h were investigated, respectively, for void content, microscopy images, mechanical properties and water absorption. The jute and coir fibers were vacuum dried before molding composite specimens. Mechanical properties indicated good adhesion between natural fibers and PP. Jute fibers, when alkali-treated with 2% concentration for 24 h, showed best improvement in tensile strength by 40% and modulus by 9%, respectively, while coir fibers, when alkali-treated with 6% concentration for 24 h, showed best improvement in tensile strengths by 62% and modulus by 17%, respectively. With 2% concentration of alkali-treatments, the elongation of jute and coir composites reached 8% and 13.5%, respectively. Moisture absorption for jute and coir composites are 50% and 60% lower than untreated fiber composites, respectively.

• Structural Engineering and Mechanics
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• 제56권6호
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• pp.1095-1113
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• 2015

Jute rope is one of the most popular materials used for composites in various industries and in civil engineering. This experimental study investigated two types of jute rope with different diameters for jute rope composite plates to determine the best combination of jute rope and carbon fiber in terms of ratio and physical and mechanical properties. Eight combinations of carbon fiber and jute rope with different percentages of carbon fiber were analyzed. Tensile tests for the jute rope composite plate and hybrid jute rope composite were conducted, and the mechanical and physical properties of the specimens were compared. Thereafter, the ideal combinations of jute rope with an optimum percentage of carbon fiber were identified and recommended. These particular combinations had tensile strengths that were 2.23 times and 1.76 times higher than other varieties in each type.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.111-115
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• 2005

Recently, natural fibers draw much interests in composite industry due to low cost, light weight, and environment-friendly characteristics compared with glass fibers. In this study, mechanical properties were evaluated for two extreme cases of jute fiber orientations, i.e. the unidirectional yarn composites and the felt fabric composites. Samples of jute fiber composites were fabricated by RTM process using epoxy resin, and tensile, compression, and shear tests were conducted. As can be expected, unidirectional fiber specimens in longitudinal direction showed the highest strength and modulus. Compared with glass/epoxy composites of the similar fabric architecture and fiber volume fraction, the tensile strength and modulus of jute felt/epoxy composites reached only 40% and 50% levels. However, the specific tensile strength and modulus increased to 80% and 90% of the glass/epoxy composites. The main reason for the poor mechanical properties of jute composites is associated with the weak interfacial bonding between fiber and matrix. The effect of surface treatment of jute fibers on the interfacial bonding will be examined in the future work.

• 한국기계가공학회지
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• 제18권12호
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• pp.28-37
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• 2019

Due to their flexible tailoring qualities, composites have become fascinating materials for structural engineers. While the research area of fiber-reinforced composite materials was previously limited to synthetic materials, natural fibers have recently become the primary research focus as the best alternative to artificial fibers. The natural fibers are eco-friendly and relatively cheaper than synthetic fibers. The main concern of current research into natural fiber-reinforced composites is the prediction and enhancement of the effective material properties. In the present work, finite element analysis is used with a numerical homogenization approach to determine the effective material properties of jute fiber-reinforced epoxy composites with various volume fractions of fiber. The finite element analysis results for the jute fiber-reinforced epoxy composite are then compared with several well-known analytical models.

• Composites Research
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• 제27권3호
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• pp.96-102
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• 2014

본 연구에서는 황마 단섬유 강화 폴리유산을 코어 폼으로 하고 연속 유리 섬유 강화 폴리유산을 외곽 스킨으로 하는 샌드위치 패널 구조의 황마 단섬유 강화 폴리유산 복합재료를 제작하였고, 황마 섬유 무게 비에 따른 복합재의 굽힘 특성을 관찰하였다. 코어 폼의 밀도는 0.31-0.67 $g/cm^3$ 기공함량비는 0.51-0.71이었다. 최대 굽힘강도는 황마 섬유 무게비 12.5 wt.%에서 92.7 MPa, 최대 굽힘 탄성계수는 황마 섬유 무게비 30.0 wt.%에서 7.58 GPa 으로 측정되었다. 경제성 분석을 실시했으며 적용 부재의 굽힘 강도를 향상시키기 위한 비용은 황마 섬유 무게 비가 12.5 wt.%일 때 $0.010USD/m^3/MPa$로 계산되었다.

• Advanced Composite Materials
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• 제16권4호
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• pp.385-394
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• 2007

In this study, the effect of molding condition on the tensile properties for plain woven hemp fiber reinforced green composite was examined. The tensile properties of the composite were compared with those of the plain woven jute fiber composite fabricated by the same process. Emulsion type biodegradable resin or polypropylene sheet was used as matrix. The composites were processed by the compression molding where the molding temperature and its heating time were changed from 160 to $190^{\circ}C$ and from 15 to 25 min, respectively. The following results were obtained from the experiment. The tensile property of hemp fiber reinforced polypropylene is improved in comparison with polypropylene bulk. The strength of composite is about 2.6 times that of the resin bulk specimen. Hemp fiber is more effective than jute fiber as reinforcement for green composite from the viewpoint of strength. The molding temperature and time are suitable below $180^{\circ}C$ and 20 min for hemp fiber reinforced green composite. Hemp fiber green composite has a tendency to decrease its tensile strength when fiber content is over 50 wt%.

• 접착 및 계면
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• 제8권3호
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• pp.9-15
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• 2007

표면처리에 따른 Jute 섬유 강화 폴리프로필렌 복합재료의 수화 전 후 계면 물성을 미세역학시험과 동적 접촉각으로 평가하였다. 알칼리 및 실란 커플링제 용액으로 Jute 섬유의 표면을 처리함으로 Jute 섬유와 폴리프로필렌 기지재 사이의 계면전단강도가 증가를 하였으며, 수화 이후 미처리, 알칼리 그리고 실란 커플링제 용액으로 표면처리된 Jute 섬유와 기지재 사이의 계면전단강도는 수분침투에 의해 감소하였다. 실란 커플링제 용액으로 표면처리된 Jute 섬유와 폴리프로필렌 기지재 사이의 계면전단강도는 알칼리 용액 및 미처리의 경우에 비해 높았다. 미처리, 실란 커플링제 및 알칼리 용액 처리된 Jute 섬유의 표면에너지는 동적 접촉각 측정을 통해 계산되어졌다. 수화 이후의 열역학적 접착일은 섬유와 기지재 사이의 물 중간층을 고려하여 계산하였다. 계산되어진 결과를 통해 실란 커플링제 용액으로 표면처리된 Jute 섬유와 폴리프로필렌 계면 사이가 가장 안정한 것으로 나타났다.

• Composites Research
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• 제20권1호
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• pp.23-31
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• 2007

Jute fiber Green Composite의 기계적 향상을 위한 계면특성을 향상시키기 위하여 커플링제를 도입하여 첨가량에 따른 특성변화를 실험적으로 규명하였다. Maleic anhydride grafted popolypropylene(MAPP)는 자연섬유와의 계면특성의 향상에서 물리화학적 역할을 하는 것으로 판단된다. MAPP에 의한 용융상태에서의 낮아진 수지의 점도는 흐름성이 향상되어 섬유의 계면과의 접촉 면적을 확대시킨다. 약 80mm의 jute 장섬유 mat에 maleated coupler가 혼합된 PP 복합재의 물성 향상과 열가소성수지의 물리적 변화와의 관계를 고찰하였다. 이 물리적 현상을 유동지수(MI: Melting flow index) 및 점도, contact angle, 복합재료 두께, 계면전단강도, morphology 분석 등의 인자들을 이용하여 기계적 물성 향상에 기여하는 정도를 확인하였다. 특히 유동지수(MI)와 점도, MAPP의 혼합량은, 전당강도(IFSS), 인장 및 굴곡 강도와 인장탄성률의 향상과 매우 관계가 있음을 실험 결과를 통하여 확인하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.116-120
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• 2005

In this study, composites with polypropylene(PP) and Jute fiber were prepared by compression molding technique. Generally, hydrophilic jute fibers do not adhere well to PP, which is hydrophobic. Maleic anhydride grafted polypropylene(MAPP) had been widely used as a coupling agent to improve the bonding between ligno-cellulosic fibers and PP. The coupling agent improved the tensile and flexural properties when the mechanical properties were tested by using a UTM. The mechanical properties of natural fiber composites(NFCs) by modified thermoplastics were higher than those of NFCs by unmodified thermoplastics. Fracture surfaces of the composites and the fiber orientations were investigated by scanning electron microscopy. The mechanical performance of NFCs by modified thermoplastics appeared to be improved by the enhanced interface adhesion between the fiber and the matrix.

• Elastomers and Composites
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• 제47권4호
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• pp.310-317
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• 2012

계면접착력 향상을 위해 실린더형 RF 플라즈마 발생기를 이용하여 Jute fiber의 표면을 아르곤가스로 처리하였고 최적 처리조건을 설정하였다. 플라즈마 강도, 가스압력, 및 처리시간을 변경한 후 이러한 인자들이 황마섬유 표면모폴로지, 섬유 인장강도, 및 폴리프로필렌과의 모델복합체에서 계면접착강도에 미치는 영향을 조사하였다. 플라즈마 처리인자에 따라 황마섬유의 표면은 거칠어졌다. 가스압력의 영향은 처리시간 및 플라즈마 강도의 영향보다 다소 낮게 나타났다. 플라즈마 강도와 시간에 따라 황마섬유의 강도는 약 25% 감소한 반면, 가스압력의 영향은 크게 나타나지 않았다. 계면전단강도 (IFSS)를 기준으로 결정된 최적 플라즈마 처리조건은 처리시간 30 s, 전력 40 W, 가스압력 30 mTorr로 나타났다.