• Title/Summary/Keyword: nano-cellulose

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Enhanced Dispersion of High Performance Dye-sensitized Solar Cells (분산특성이 향상된 고효율 염료감응형 태양전지)

  • Jin, En-Mei;Park, Kyung-Hee;Gu, Hal-Bon;Park, Bok-Kee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.6
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    • pp.501-505
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    • 2009
  • $TiO_2$ nano-particle paste was prepared by ethyl cellulose, $\alpha$-terpineol and bis(2-ethylhexyl) phthalate (dioxcyl phthalate) for dye-sensitized solar cells (DSSCs). Dispersion and absorbance of $TiO_2$ photoanode films was controlled by adding different amount of ethyl cellulose and $\alpha$-terpineol. The morphology of prepared $TiO_2$ films was studied by field emission scanning electron microscopy (FE-SEM) and the optical properties of $TiO_2$ films were measured by UV/vis spectra. Photovoltaic-current density was observed to determine the electrochemical response of DSSCs. Energy conversion efficiency was obtained about 7.1% at ethyl cellulose and $\alpha$-terpineol at optimal mixed ratio (as ethyl cellulose: 0.1 g; $\alpha$-terpineol: 1.5 ml) under illumination with AM 1.5($100\;Wcm^{-2}$) simulated sunlight.

Effect of the Viscosity of (Hydroxypropyl)methyl Cellulose on Dissolution Rate of Alfuzosin-HCl Granule Tablet (HPMC의 점도에 따른 염산 알푸조신 과립정제의 용출률 조절)

  • Kim, Won;Song, Byung-Joo;Kim, Dae-Sung;Kim, Su-Jin;Lee, Seon-Kyoung;Kim, Hye-Lin;Lee, Dong-Won;Khang, Gil-Son
    • Polymer(Korea)
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    • v.34 no.3
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    • pp.269-273
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    • 2010
  • The primary objective of this work is to find the optimal condition for the granule tablet formulation of alfuzosin-HCl that aims to achieve a sustained drug release. (Hydroxypropyl)methyl cellulose (HPMC) is one of the most widely used polymer as a drug formulation and therefore has been utilized in this study as an excipient. Alfuzosin-HCl granule tablet was developed using the various viscosities of HPMC and the effects of viscosity on drug release was investigated. Fourier transform-infrared (FTIR) and X-ray diffraction (XRD) were employed to investigate the chemical structure and crystallization of alfuzosin-HCl in the formulation. We prepared the granule tablet by a direct compression method and studied the release profile in the stimulated intestinal fluid (pH 6.8). As the viscosity of HPMC increased the release of alfuzosin-HCl decreased, demonstrating that controlled release of alfuzosin-HCl can be achieved by varying the viscosity of HPMC.

Effects of Alkali Treated Nano-kenaf Fiber in Polypropylene Composite upon Mechanical Property Changes (알카리로 처리된 나노케냐프 섬유가 PP 복합소재 내에서 기계적 물성 변화에 미치는 영향)

  • Oh, Jeong Seok;Lee, Seong-Hoon;Kim, Kwang-Jea
    • Polymer(Korea)
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    • v.39 no.1
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    • pp.99-106
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    • 2015
  • The surface of nano-kenaf containing cellulose fibers was treated with alkali (NaOH) and their effects on the physical properties of the polypropylene (PP) composite were investigated. The treatment of alkali on the fibers increased the melt flow index (M.I.), elongation%, and impact strength, while it decreased the tensile strength, flexural modulus and heat deflection temperature (HDT) of the compound compared to the untreated one. It seemed the alkali treatment on the nano-kenaf fiber changed the character of the fiber due to removal of impurities and chemicals on the surface and resulted in decreased interfacial adhesion between the nano-fiber surface and the PP matrix and changed the character of the PP.

Fabrication of Porous Cellulose Acetate Propionate/Polybutylene Succinate Microfibers by High Speed Centrifugal Spinning (초고속 원심방사에 의한 아세트산프로피온산 셀룰로오스/폴리부틸렌 숙시네이트 다공성 마이크론 섬유 제조)

  • Tae Young Kim;Mi Kyung Kim;Jinsoo Kim;Jungeon Lee;Jae Hoon Jung;Youngkwon Kim;Tae Hyeon Kim;Ki Young Kim;Jeong Hyun Yeum
    • Textile Coloration and Finishing
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    • v.35 no.4
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    • pp.239-245
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    • 2023
  • Cellulose is an abundant biodegradable material in nature with excellent properties, but due to its poor processability, it has been widely studied for processing through modification. Cellulose acetate propionate (CAP) is a cellulose derivative in which the hydroxyl group of cellulose is replaced by acetyl and propionyl groups. CAP has several advantages, such as excellent solubility, structural stability, light and weather resistance, and good transparency. Porous nanofibers with excellent specific surface area, which can be applied in various fields, can be easily formed by the phase separation method using highly volatile solvents. High speed centrifugal spinning is a nano/micro fiber preparation method with advantages such as fast spinning and easy alignment control. In this study, a CAP/polybutylene succinate (PBS) spinning solution with chloroform as solvent was prepared to prepare porous microfibers and the fiber morphology was examined as a function of the disk rotation speed in an high speed centrifugal spinning device.

Study on the Eco-friend Frame Sheet with Improved Glasses Temple's Insertion-processibility by Blending Plasticizer of High Specific Heat (친환경 안경테 판재의 심입 가공성 향상을 위한 고비열 가소제 혼입에 관한 연구)

  • Seo, Young Min;Lee, Hae Sung;Lee, Sung Jun;Jung, Sang Won;Kim, Hyun-Chul;Kim, Eun Joo;Go, Young Jun;Choi, Jin Hyun;Lee, Se Guen
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.1
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    • pp.11-17
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    • 2013
  • Purpose: To improve glasses temple's insert processibility of CA/PEG blend, triacetin with higher specific heat values in the processing temperature range is used as second plasticizer. Methods: The total amount of plasticizer is fixed at 30 wt% by CA. To determine optimal CA/PEG/triacetin blend for glasses frame, blends with different composition ratio were examined by various analysis: thermal properties, mechanical properties, glossiness. Results: Specific heat of the CA/PEG blend increased as the content of triacetin. In CA/PEG/triacetin blends, as triacetin concentration is increased, glass transition temperature is decreased and heat conservation rate of composites is increased. Furthermore, CA/PEG/triacetin blend exhibited higher mechanical properties and similar gloss characterization with CA/PEG blend. Conclusions: It is possible to improve the processibility inserting metal support to CA temple through varying the weight ratio of PEG/triacetin. The extruded sheets of CA/PEG/triacetin blend had better glossiness and mechanical properties than those of CA/PEG blend.

Development of the Functional Films Coated with Nano-TiO2 Particles for Food Packaging and Removal of Off-flavor from Soybean Sprouts (나노 TiO2를 적용한 식품 포장 필름 개발 및 콩나물의 이취 제거)

  • Choi, Yeonwook;Jeon, Kyu Bae;Song, Kihyeon;Kim, Jai Neung
    • Korean Journal of Food Science and Technology
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    • v.47 no.6
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    • pp.733-737
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    • 2015
  • For testing the ultraviolet (UV)-blocking property of functional films coated with Nano-$TiO_2$ particles, UV-Vis spectra of oriented polypropylene (OPP) films uncoated and coated with $TiO_2$ of 3% and 5% in Polyurethane (PU) and polyvinyl butyral (PVB)-Cellulose binders were measured. The result of UV-Vis analyses showed that the film coated with 5% $TiO_2$ in PVB binders had a significant effect on UV protection of 90% compared with the film uncoated. Also The result of The photodegradation of methylene blue (MB), OPP films coated with 5% in both PU and PVB binders had a high photocatalytic activity for MB degradation. To evaluate the effect of the developed functional film coated with Nano-$TiO_2$ particles, fresh soybean sprouts were used. Nano-$TiO_2$ coated film was observed to decompose the off-flavor produced by soybean sprouts within packages during distribution, but uncoated film did not. Therefore, Nano-$TiO_2$ coated film package could give the greatest effect in extending the shelf life of soybean sprouts.

Advanced 'green' composites

  • Netravali, Anil N.;Huang, Xiaosong;Mizuta, Kazuhiro
    • Advanced Composite Materials
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    • v.16 no.4
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    • pp.269-282
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    • 2007
  • Fully biodegradable high strength composites or 'advanced green composites' were fabricated using yearly renewable soy protein based resins and high strength liquid crystalline cellulose fibers. For comparison, E-glass and aramid ($Kevlar^{(R)}$) fiber reinforced composites were also prepared using the same modified soy protein resins. The modification of soy protein included forming an interpenetrating network-like (IPN-like) resin with mechanical properties comparable to commonly used epoxy resins. The IPN-like soy protein based resin was further reinforced using nano-clay and microfibrillated cellulose. Fiber/resin interfacial shear strength was characterized using microbond method. Tensile and flexural properties of the composites were characterized as per ASTM standards. A comparison of the tensile and flexural properties of the high strength composites made using the three fibers is presented. The results suggest that these green composites have excellent mechanical properties and can be considered for use in primary structural applications. Although significant additional research is needed in this area, it is clear that advanced green composites will some day replace today's advanced composites made using petroleum based fibers and resins. At the end of their life, the fully sustainable 'advanced green composites' can be easily disposed of or composted without harming the environment, in fact, helping it.

Partially Carbonized Poly (Acrylic Acid) Grafted to Carboxymethyl Cellulose as an Advanced Binder for Si Anode in Li-ion Batteries

  • Cho, Hyunwoo;Kim, Kyungsu;Park, Cheol-Min;Jeong, Goojin
    • Journal of Electrochemical Science and Technology
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    • v.10 no.2
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    • pp.131-138
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    • 2019
  • To improve the performance of Si anodes in advanced Li-ion batteries, the design of the electrode plays a critical role, especially due to the large volumetric expansion in the Si anode during Li insertion. In our study, we used a simple fabrication method to prepare Si-based electrodes by grafting polyacrylic acid (PAA) to a carboxymethyl cellulose (CMC) binder (CMC-g-PAA). The procedure consists of first mixing nano-sized Si and the binders (CMC and PAA), and then coating the slurry on a Cu foil. The carbon network was formed via carbonization of the binders i.e., by a simple heat treatment of the electrode. The carbon network in the electrode is mechanically and electrically robust, which leads to higher electrical conductivity and better mechanical property. This explains its long cycle performance without the addition of a conducting agent (for example, carbon). Therefore, the partially carbonized CMC-g-PAA binder presented in this study represents a new feasible approach to produce Si anodes for use in advanced Li-ion batteries.

Introduction to Ionic Polymer-Metal Composite Actuators and Their Applications (이온성 고분자-금속 복합체 작동기의 소개 및 이의 응용)

  • Jeon, Jin-Han;Oh, Il-Kwon
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.11
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    • pp.1242-1250
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    • 2011
  • Several biomimetic artificial muscles including the electro-active synthetic polymers (SSEBS, PSMI/PVDF, SPEEK/PVDF, SPSE, XSPSE, PVA/SPTES and SPEI), bio-polymers (Bacterial Cellulose and Cellulose Acetate) and nano-composite (SSEBS-CNF, SSEBS-$C_{60}$, Nafion-$C_{60}$ and PHF-SPEI) actuators are introduced in this paper. Also, some applications of the developed biomimetic actuators are explained including biomimetic robots and biomedical active devices. Present results show that the developed electro-active polymer actuators with high-performance bending actuation can be promising smart materials applicable to diverse applications.