• 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.

• Advanced Composite Materials
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• 제16권4호
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• pp.349-360
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• 2007

Recently, natural fiber reinforced composite is attracting attention and considered as an environmentally friendly material. Usually cellulosic fibers are used to reinforce the composites, but some protein fibers such as silk and wool serve the same purpose. In this paper, we proposed a method of producing artistic composite from artistic fabric by using silk fiber reinforced biodegradable plastic, which is designated as 'silk composite', for reinforcement. In order to expand applications of the silk composite, we performed the compression molding of decorative laminates with woody material, which was selected as a core material, and examined the properties of molded decorative laminates with various content of the silk composite. Since plywood and medium-density fiberboard (MDF) are widely used for decorative laminates, we selected them as core materials. As a result, flexible decorative laminates with high flexural strength were obtained by compounding the silk composite with wood materials.

• Journal of the Korean Wood Science and Technology
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• 제21권2호
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• pp.31-37
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• 1993

Composites of styrene polymers with woody fibers were prepared, and the effect of compatibilizers on their mechanical properties was evaluated. To improve the compatibility of wood fibers and the matrix polymers, styrene-maleic anhydride copolymer(SMA) and maleic anhydride-modified polymers were used as compatibilizers. As results, maleic anhydride-modified polystyrene and SMA were proved to improve the tensile strength of the molded composites, and also were evaluated as good compatibilizers for the wood fiber polystyrene composite. Cellulosic fiber (dissolving pulp) provided better reinforcement than lignocellulosic fiber(thermomechanical pulp). On the contrary in the case of the composite of wood fiber and acrylonitrile-butadiene styrene copolymer(ABS), SMA and maleic anhydride-modified acrylonitrile-butadiene-styrene copolymer(MABS) did not act as compatibilizers. However, MABS was evaluated as a good polymer matrix to make wood fiber reinforced composite. The tensile properties of the composites of wood fiber and MABS were superior than those of wood fiber-ABS composites.

• 펄프종이기술
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• 제42권2호
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• pp.53-60
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• 2010

Kudzu vine (Pueraria lobata) is a perennial plant and spreads all around in South Korea. Recently the use of leaves, stems and roots of kudzu vine has been investigated in many fields. However, the research on kudzu fibers has not been performed in korean pulp and paper industry. As the stems and roots of kudzu were estimated to contain cellulosic fibers, the possibility of producing a raw material from kudzu fibers in pulp and paper mills was investigated in this study. The stems and roots of kudzu were collected in woods, and then the chemical composition and ash contents was measured. To acquire kudzu pulp, kraft pulping and bleaching of kudzu roots were carried out sequently. After making kudzu pulp, freeness and fiber length were measured, and handsheets was also prepared with kudzu pulp and the properties of handsheets were determined. Consequently, kudzu fibers have lower holocellulose contents than wood fibers and other non-wood fibers. Average fiber length is shorter than that of Sw-BKP, but shows the same level as that of Hw-BKP. The handsheet made from kudzu pulp shows the bulkier structure than those made from Hw-BKP and Sw-BKP.

• 펄프종이기술
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• 제48권2호
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• pp.5-12
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• 2016

White waste papers are very important resources in the paper industry, but their use is limited because of the residual of fluorescent whitening agent (FWA). So the removal of FWAs from waste paper is an important task in the recycling process to improve the use of recycled resources. In this study, we focused on the FWAs used for surface treatments and carried out physical and chemical treatments to remove them from white waste papers. The white waste papers were disintegrated with a surfactant in different pH and temperature conditions, and then handsheets were made for the measurement of the fluorescence index, which is proportional to the amount of FWAs on papers. The effect of the flotation process on the removal of FWAs after disintegration was also investigated. The fluorescence index decreased as the disintegration time increased, but over a relatively long time, the fluorescence index increased again, which indicated the readsorption of the FWAs detached from the cellulosic fibers of the white waste papers. The lowest fluorescence index was shown when the waste papers were disintegrated with a 0.3% surfactant addition at pH 10 and at $45^{\circ}C$. However, the flotation treatment was not effective, because the flotation induced contact between the detached FWAs and the cellulosic fibers, and re-adsorption occurred.

• 한국가구학회지
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• 제21권2호
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• pp.126-132
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• 2010

High wear resistances are obtained with an additional coating of the surface of the decor film in the same operation of impregnating with low viscosity melamine resin by liquid overlay system. The cellulosic fibers have a good adhesion to the corundum particles and keep them sufficiently homogeneous in the blend with the resin. The amount of these fibers in nearly as big as it is in a common overlay in relation to the resin. Therefore these fibers keep the resin inside during the press process and consequently very the surface of the decor print of the film. That means that the corundum particles are equally dissipated throughout the entire layer over the decor. The change of the color of the print is nearly not visible as the particles are almost equally dissipated. Looking to the flooring purposes of liquid overlay one can see that by the lesser exposure of the corundum particles on the very surface, there is no longer an abrasive surface but a feeling like a normal melamine surface.

• 한국응용과학기술학회지
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• 제27권2호
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• pp.168-174
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• 2010

In this research, an effective method for reducing the fibrillation of lyocell fibers, which are spun from a solution of cellulose in N-methyl morpholine-N-oxide(NMMO), through consecutive chemical treatments. Undried solution-spun cellulosic fiber was firstly treated with 10 to 30 wt% of multifunctional crosslinking agents, such as ethylene glycol poly(3-chloro-2-hydroxypropyl) ether, and then dipped into alkaline solution to introduce epoxy functions. Finally steam condition was applied to occur a chemical crosslinking in order to reduce the fibrillation on the surface of fibers. Fibrillation was also reduced significantly by adding extra $Na_2SO_4$ in NaOH solution. In addition, Antifibrilllated lyocell fibers show the slightly higher dyeability(4 %) to Cibacron Blue without serious reduction of mechanical properties.

• 펄프종이기술
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• 제29권3호
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• pp.26-33
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• 1997

The bacterial celluloses are very different in its physical, chemical and morphological structures compared to wood cellulose. These fibers have many unique properties that are potentially and commercially beneficial. This study was aimed to elucidate the production of bacterial celluloses and to improve their physical properties by chemical pretreatment. Bacterial celluloses produced by static culture had gel-like pellicle structure. The pellicle thickness was increased with the increasing time, and its layer was about 1.8cm after one-month incubation. The pellicles extruded from the cells of Acetobacter had a non-crystalline structure during initial growing stages, gradually getting crystaliyzed with the incubation time elapse, and eventually fumed to the cellulose I crystals. Young＇s modulus of bacterial cellulose sheet was increased with increasing NaOH concentration, and resulted in the highest at 5% NaOH concentration. Similar results with NaClO3 pretreatment can be observed. Too concentrated alkali solutions induced the destruction of cellulose fibrils and changed the mechanical properties of the sheets. These alkaline pretreatment have removed non-cellulosic components(NCC) from the bacterial cellulose, and enhanced inter-abrillar bonding by direct close contact among cellulosic fibrils.

• 한국의류학회지
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• 제30권7호
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• pp.1025-1033
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• 2006

Kenaf bast can be obtained by decortication of Kenaf stem. Kenaf fibers are much more rough than cotton fiber because they include impurities as pectin, lignin and hemicellulose besides cellulose. The purpose of this research is to investigate the distribution of kenaf fiber length and diameter during the processes of removing impurities. To remove pectin, kenaf bast was retted chemically. A half of the retted kenaf fiber bundle were scoured and bleached. The other half one were treated with $NaClO_2$ solution to remove lignin, and were treated with sodium hydroxide solution to remove hemicellulose. Four kinds of specimens that were obtained for investigating physical characteristics. Length and diameter of 100 fibers on each specimen was measured. The tensile strength of 100 fiber bundles were measured. And also the color values of them were measured with spectrocolorimeter. The length of retted kenaf fiber was 16.97cm. Then it decreased to 11.43cm after bleaching. Kenaf fiber bundles could be finer by chemical processes that remove non-cellulosic materials. The thickness of retted fiber was $132{\mu}m$. And after undergoing the chemical processes to remove non-cellulosic materials, the thickness of kenaf fiber became finer as $73{\mu}m$. Tensile strength of the retted kenaf fiber bundles was 11.37Mpa. The retted kenaf fiber lost their strength as 22.6% by bleaching and as 18.3% by treatment for removing lignin. The retted kenaf fiber showed low whiteness as 56.48 of L*value. After bleaching, the kenaf fibers have creamy white color and their whiteness got 90.02 of L*value. After the treatment for removing hemicellulose, the kenaf fibers also have creamy white color and their whiteness got L* value of 79.02.

• 펄프종이기술
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• 제40권1호
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• pp.62-67
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• 2008

Biocomposite was fabricated with biodegradable polymer and natural fiber that has potential to be used as replacement for glass fiber reinforced polymer composite with the benefits of low cost, low density, acceptable specific strength, biodegradability, etc. Until now, mostly natural cellulosic fibers on land have been used as reinforcement for biocomposite. The present study focused on investigating the fabrication and the characterization of biocomposite reinforced with red algae fibers from the sea. The bleached red algae fiber (BRAF) showed very similar crystallinity to the wood cellulose. It has high stability against thermal degradation (maximum thermal decomposition temperature of 359.3$^{\circ}C$) and thermal expansion. Biocomposites reinforced with BRAF have been fabricated by a compression molding method and their mechanical and thermal properties have been studied. The storage modulus and the thermomechanical stability of PBS (polybuthylenesuccinate) matrix are markedly improved by reinforcing with the BRAF. These results indicate that red algae fiber can be used as an excellent reinforcement of biocomposites, which are sometimes called as "green-composites" or "eco-composites".