• Title/Summary/Keyword: dispersity

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Synthesis and Characterization of Sulfonated Polyetherimide (Sulfonated Polyetherimide 합성 및 특성)

  • 김완주;최남석;최중구;김인철;김종호;탁태문
    • Membrane Journal
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    • v.9 no.1
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    • pp.10-16
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    • 1999
  • In this study, polyetherimide with pellet state was sulfonated with a chlorosulfonic acid. The volume ratio of carbon tetrachloride (CCI$_4$/1,2-dichloroethane (DCE) was 5/1. Therefore, sulfonated polyetherimide of anionic charge and more hydrophilicity were produced. The optimum reaction conditions of sulfonation were that PES/CSA mole ratio was I/I, temperature were lO$^{\circ}$ and reaction time were 3hr. SPEls having ion capacity in the range of 0.2-1.2meq/mg were synthesized. Through FT-IR, sulfonic acid peak was shown at 1020cm$^{-1}$ and 1170cm$^{-1}$ Polymer dispersity index was broad and we confirmed that PEl was hydrophilzed in the measure of contact angle.

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The Influence of Functionalization of the Fe3O4 Nanoparticle on its Dispersion Property

  • Han, Jin Soon;An, Gye Seok;Park, Bong Geun;Choi, Sung-Churl
    • Journal of the Korean Ceramic Society
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    • v.55 no.1
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    • pp.80-84
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    • 2018
  • In this study, to improve the dispersity of $Fe_3O_4$ nanoparticles, dispersion properties were considered with various types of functionalization of $Fe_3O_4$ nanoparticles. Due to its high surface area, the electrically neutral state of its surfaces, and its magnetic momentum, $Fe_3O_4$ nanoparticles are easily aggregated in solution. In order to prevent aggregation, $Fe_3O_4$ nanoparticles were functionalized with carboxyl and amine groups in the form of a polymer compound. Carboxyl and amine groups were attached to the surface of $Fe_3O_4$ nanoparticles and the absolute value of the zeta potential was found to be enhanced by nearly 40 eV. Furthermore, the morphology and the magnetic property were analyzed for the application of $Fe_3O_4$ nanoparticles as a magnetic fluid.

Synthesis of Water-Dispersible Maghemite Nanocrystals using 6-Aminohexanoic Acid as a Capping Agent (6-Aminohexanoic Acid를 이용하여 물에 분산되는 Maghemite 나노입자의 합성)

  • Yu, Taekyung
    • Korean Chemical Engineering Research
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    • v.51 no.3
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    • pp.403-406
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    • 2013
  • This paper describes a simple route to synthesis of water-dispersible monodisperse maghemite (${\gamma}-Fe_2O_3$) nanocrystals using 6-aminohexanoic acid (AHA) as a stabilizer. The water-dispersible ${\gamma}-Fe_2O_3$ nanocrystals with an average size of 5 nm were obtained simply by addition of $Fe(CO)_5$ into an octyl ether solution containing AHA at $195^{\circ}C$ under argon condition. As-prepared AHA coated ${\gamma}-Fe_2O_3$ nanocrystals exhibited highly crystallinity and magnetic property while keeping a good dispersity in an aqueous phase. We also obtained water-dispersible AHA coated ${\gamma}-Fe_2O_3$ nanocrystals using ligand-exchange method, demonstrating that AHA can be a good candidate for preparing water-dispersible uniform metal oxide nanocrystals.

A Development on the Non-Photomask Plate Making Technology for Screen Printing (II) (포토마스크가 필요 없는 스크린 제판 기술 개발(II))

  • Park, Kyoung-Jin;Kang, Hyo-Jin;Kim, Sung-Bin;Nam, Su-Yong;Ahn, Byung-Hyun
    • Journal of the Korean Graphic Arts Communication Society
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    • v.26 no.2
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    • pp.45-54
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    • 2008
  • We have manufactured a photoresist which has excellent dispersity and good applying property due to 330 cps of viscosity for environment-friendly and economical maskless screen plate making. And the photoresist applied on the screen stretched was exposed with mask by UV-LED light source so we could manufacture the photoresist which proper for the UV light source. And it was developed by air spray with $1.7\;kgf/cm^2$ of injection pressure. Because of the excellence of power and resolution of the UV-LED light sourse, the pencil hardness and solvent resistance of curing photoresist film were excellent as those of conventional photoresist film. Moreover the $100{\mu}m$-width stripe image which has sharp edges was formed. So we confirmed a possibility of dry development process by air spray method.

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Influence of the Variation of the Coating Color Composition and Characteristics of Inks on the Printability of the Coated Paper (도공액 조성변화와 잉크 물성변화가 인쇄품질에 미치는 영향)

  • Koo, Chul-Whoi;Ha, Young Baeck
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.46 no.5
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    • pp.1-8
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    • 2014
  • In this study, the influence of the physical properties of ink such as ink dispersity and emulsified amount on the printability of a coated paper was investigated with seven kinds of cyan inks. In addition, two kinds of coating formulations were tested to evaluate the effect of coating structure on the coated paper printability. It was found that the cyan ink with $2{\mu}m$ pigment size had the best dispersibility and hence the ink showed a best ink density on the two kinds of coated papers. When the emulsified ink A with IPA 20 wt% had a lower viscosity than emulsified ink B with IPA 10 wt%, the emulsified ink A showed relatively high value of the ink transfer rate in comparison with emulsified ink B. Despite the high value of ink transfer rate, the coated paper did not show a good printability because those inks with low viscosity due to a strong emulsification were easy to make print mottle on the coated paper.

Machine learning modeling and DOE-assisted optimization in synthesis of nanosilica particles via Stöber method

  • Moradi, Hiresh;Atashi, Peyman;Amelirad, Omid;Yang, Jae-Kyu;Chang, Yoon-Young;Kamranifard, Telma
    • Advances in nano research
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    • v.12 no.4
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    • pp.387-403
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    • 2022
  • Silica nanoparticles, which have a broad range of sizes and specific surface features, have been used in many industrial applications. This study was conducted to synthesize monodispersed silica nanoparticles directly from tetraethyl orthosilicate (TEOS) with an alkaline catalyst (NH3) based on the sol-gel process and the Stöber method. A central composite design (CCD) is used to build a second-order (quadratic) model for the response variables without requiring a complete three-level factorial experiment. The process was then optimized to achieve the minimum particle size with the lowest concentration of TEOS. Dynamic light scattering and scanning electron microscopy were used to analyze the size, dispersity, and morphology of the synthesized nanoparticles. After optimization, a confirmation test was carried out to evaluate the confidence level of the software prediction. The results revealed that the predicted optimization is consistent with experimental procedures, and the model is significant at the 95% confidence level.

Artificial neural fuzzy system and monitoring the process via IoT for optimization synthesis of nano-size polymeric chains

  • Hou, Shihao;Qiao, Luyu;Xing, Lumin
    • Advances in nano research
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    • v.12 no.4
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    • pp.375-386
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    • 2022
  • Synthesis of acrylate-based dispersion resins involves many parameters including temperature, ingredients concentrations, and rate of adding ingredients. Proper controlling of these parameters results in a uniform nano-size chain of polymer on one side and elimination of hazardous residual monomer on the other side. In this study, we aim to screen the process parameters via Internet of Things (IoT) to ensure that, first, the nano-size polymeric chains are in an acceptable range to acquire high adhesion property and second, the remaining hazardous substance concentration is under the minimum value for safety of public and personnel health. In this regard, a set of experiments is conducted to observe the influences of the process parameters on the size and dispersity of polymer chain and residual monomer concentration. The obtained dataset is further used to train an Adaptive Neural network Fuzzy Inference System (ANFIS) to achieve a model that predicts these two output parameters based on the input parameters. Finally, the ANFIS will return values to the automation system for further decisions on parameter adjustment or halting the process to preserve the health of the personnel and final product consumers as well.

Synthesis and Characteristics of Zirconium Hybridized Polycarbosilane (지르코늄 혼성 폴리카르보실란의 합성 및 특성)

  • Kang, Phil-Hyun;Yang, Hyun-Soo
    • Applied Chemistry for Engineering
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    • v.9 no.6
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    • pp.791-797
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    • 1998
  • As organosilicon based preceramic polymer, new zirconium hybridized polycarbosilane having a good thermal stability and forming stage was synthesized. Oxidative stability(infusibility) and mechanical property of this polymer during the thermal curing process and heat treatment were examined. Prepared zirconium hybridized polycarbisilane (PZC) was spun into fiber at $250{\sim}270^{\circ}C$. Spinnability of PZC polymer having a molecular weight of 1000 to 1400 and having a dispersity<2 was good. The thermal curing process of the PZC fiber was done at 140 to $200^{\circ}C$. The mechanical properties of PZC ceramic fiber depend on curing temperature of PZC as precursor of PZC ceramic fiber. It was found that the optimum curing temperature was variable with the molecular weight of PZC. The cured PZC fiber need constant gel fraction to have good tensile strength.

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Comparative Studies on Three Kinds of Reductants Applicable for the Reduction of Graphene Oxide (그래핀 옥사이드의 환원 반응에 적용되는 3종류 환원제에 관한 비교 연구)

  • Park, No Il;Park, Wan-Su;Lee, Seul Bi;Lee, Seong Min;Chung, Dae-Won
    • Applied Chemistry for Engineering
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    • v.26 no.1
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    • pp.99-103
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    • 2015
  • We conducted reduction reactions of graphene oxide (GO) using three selected reductants. The conductivity and solubility of three kinds of the reduced graphene oxides (RGOs) were examined based on the degree of reduction. When the ethylene glycol (EG) was used as a reductant, the reduction reaction did not sufficiently progress and as a result the conductivity of RGOs was observed to be relatively low. For RGOs made by hydrazine (HZ) and thiourea dioxide (TU), we observed no significant differences in the degree of the reduction, conductivity and dispersity in water. However, RGO prepared by TU showed an exceptionally good solubility in N-methylpyrrolidone, and the solution was stable for more than 4 months.

Spray Drying of Lignocellulose Nanofibril (LCNF) and Characterization of Spray-dried LCNF (리그노셀룰로오스 나노피브릴의 분무건조 및 건조물의 특성)

  • Park, Chan-Woo;Han, Song-Yi;Lee, Seung-Hwan
    • Journal of the Korean Wood Science and Technology
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    • v.45 no.3
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    • pp.288-296
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    • 2017
  • In this study, the effect of spray-drying conditions and surfactant addition on the spray-drying yield, morphological characterization, size distribution and re-dispersity in water of spray-dried lignocellulose nanofibril (LCNF) were investigated. The freeze-dried LCNF after solvent exchange had linear fiber morphology with a diameter of 70-300 nm, and the spray-dried LCNF showed rod-like particle morphology. The spray-drying yield and particle size of spary-dried LCNF at $140^{\circ}C$ was highest and smallest, respectively. As LCNF concentration and blowing rate decreased and increased, respectively, the spray-drying yield and particle size were increased. The highest spray-drying yield was found at distearyl dimethyl ammonium chloride (DDAC) addition of 10 phr at $140^{\circ}C$. As the particle size decreased and the DDAC content increased, filtration time of spray-dried LCNF in water was decreased and increased, respectively.