• Title/Summary/Keyword: dispersity

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Effects of Intra-particle Composition on the Adhesive Properties and Water Dispersity of Water Dispersible Acrylic Emulsion Pressure Sensitive Adhesive (입자 내 조성 변화가 수분산성 아크릴 에멀젼 점착제의 점착 물성과 수분산성에 미치는 영향)

  • Seo, In Seon;Lee, Myung Cheon
    • Applied Chemistry for Engineering
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    • v.18 no.5
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    • pp.444-448
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    • 2007
  • The effects of intra-particle composition on the adhesive properties and water dispersity of acrylic emulsion type pressure sensitive adhesives (PSAs) were investigated. In the case of PSA having uniform intra-particle composition, the higher holding strength made the water dispersity lower. By changing the intra-particle composition in hard core/soft shell type, however, it was possible to get PSAs showing both high holding strength and water dispersity. When the weight ratio of MAA/AA is 4/1, high holding strength, but low initial tack and very low water dispersity were observed in both cases of higher contents of (AA+MAA) in core and shell area. When the weight ratio of MAA/AA is 1/4, however, higher water dispersity and lower holding strength were indicated in the case of higher contents of (AA+MAA) in shell area.

Study on the Electrical Conductivity in Polysiloxane/Metal Composite Containing Metal Oxide (금속산화물을 포함한 변성폴리실록산/금속 복합체의 전기 전도성 연구)

  • Im, Hyungu;Kim, Jooheon
    • Applied Chemistry for Engineering
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    • v.20 no.3
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    • pp.307-312
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    • 2009
  • The block-co-polymer type thermosetting polysiloxane coordinated with metal oxide was synthesized to investigate the effect of metal oxide on the dispersity of metal powder in the polysiloxane/metal composite material. The metal powder in the polysiloxane/metal composite materials is better dispersed with metal oxide complex polysiloxane than the case without metal oxide. To understand the effect of quantities of metal oxide on the polysiloxane chain, the various polysiloxanes with different ratios of block unit were synthesized. Electrical conductivity was interpreted by percolation threshold theory to understand the dispersity of dense composite. The behavior of conductivity was in good agreement with theoretical value. The critical value was decreased as the quantities of metal oxide are increased. As a result, as the metal oxide increased on the polymer chain, the dispersity of metal filler was increased.

Effect of Dispersant Contents on the Dispersity of Conductive Carbon-black and Properties of Screen-printed Source-drain Electrodes for OTFTs (분산제 함량에 따른 전도성 카본블랙의 분산 특성 및 스크린 인쇄된 OTFTs용 소스-드레인 전극 물성)

  • Lee, Mi-Young;Bae, Kyung-Eun;Kim, Seong-Hyun;Lim, Sang-Chul;Nam, Su-Yong
    • Polymer(Korea)
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    • v.33 no.5
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    • pp.397-406
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    • 2009
  • We have fabricated source-drain electrodes for OTFTs using a screen-printing technique with carbon-black pastes as conductive paste. And effects of dispersants contents (SOP 10-40%) on the dispersity of carbon-black pastes and characteristics of screen-printed source-drain electrodes for OTFTs using two types of dispersants (DB-2150, DB-9077) were investigated. As contents of both dispersants were increased the dispersity of carbon-black mill-bases was improved, whereas the carbon-black pastes exhibited different dispersion characteristics. For the case of DB-2150, the dispersity of the pastes was improved with increasing dispersant content and the storage modulus G' in their rheology characteristics were reduced. But, for the DB-9077, the storage modulus G' of pastes were increased with dispersant content due to the flocculated network structure formed by interactions among carbon-black powders and dispersants. But, since this flocculated network structure of the pastes using DB-9077 resulted in the conduction path of carbon-black structures, the conductivities of screen-printed electrodes and mobilities of the OTFTs with them were better than those using pastes with DB-2150.

Comparison between Acid and Heat Treatment for Capacity Enhancement of RuO2/MWNT Composite Electrode Materials for Ultracapacitor (울트라캐패시터용 RuO2/MWNT 복합 전극재료의 용량개선을 위한 산처리 및 열처리 효과 비교)

  • Kim, Yong-Tae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.1
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    • pp.65-69
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    • 2010
  • In this study, we compared two methods(an acid treatment in strong acid reflux and a heat treatment in air atmosphere) for hydrophilic surface treatment of multi-walled carbon nanotubes(MWNT) to enhance the capcity of $RuO_2$/MWNT composite electrode materials for ultracapacitor. Both treatments generated a number of defects on the surface of MWNT by the breakage of $\pi$ bond in graphene layer at which carboxyl groups were introduced. However, the degree of hydrophilicity generated by strong acid treatment was higher than that by heat treatment in air, which was revealed by the quantitative measurement of surface carboxyl groups by using Boehm titration. The increased hydrophilicity save rise to an improved dispersity of $RuO_2$ nanoparticles on MWNT. Finally, the improved dispersity resulted in the capacity enhancement of composite electrode materials for ultracapacitor.

Study on Heat-shield Property of Surface-treated Inorganic Oxide Particles (표면처리된 무기산화물 입자의 열차단 특성에 관한 연구)

  • Kim, Dong Ho;Kim, Gu Ni
    • Journal of Adhesion and Interface
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    • v.14 no.1
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    • pp.28-35
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    • 2013
  • In this study, we produced heat-shield coating materials using surface-treated Ga-doped ZnO (GZO) and investigated the dispersity of particle, visible light transmittance, ultraviolet light cut off, infrared light cut-off, heat-shielding property by surface-treating compounds and treatment conditions. In the case of using IPA or acryl binder for heat-shield coating, the dispersity of inorganic oxide particles was poor but in the case of using surface-treated inorganic oxide particles by hybrid compound having urethane (urea) group, acryl group and silica, dispersity of particle, visible light transmittance and haze were improved. We used the measurement kit and sunlamp for measuring heat-shielding property and confirmed that the internal temperature of the measurement kit using heat-shield film was lower more than $4.8^{\circ}C$ in comparison with using PET film for itself.

Effect of glass beads on dispersion properties of EVA/MWCNT foams (유리비드가 EVA/MWCNT 발포체의 분산특성에 미치는 영향)

  • Kim, Taeyoon;Lee, Seunghyun;Ching, Ildoo
    • Journal of Adhesion and Interface
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    • v.19 no.2
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    • pp.68-73
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    • 2018
  • In this study, conductive EVA foams including multi-wall carbon nanotubes (MWCNT), glass beads were prepared. The electrical conductivity and physical properties of the foams were confirmed with varying amount of MWCNT, mixing time, and amount of glass beads. The electrical conductivity increased with the amount of MWCNT. Dispersity of MWCNT in EVA foams were improved with glass beads. It can be suggested that conductive EVA foams can be successfully prepared with improved dispersity of MWCNT in ethylene-vinyl acetate by using glass beads.

Integration of Graphene Oxide Into PAN Nanofibers with Improved Physical Property (Graphene Oxide를 활용한 PAN 나노섬유 제조 및 물리적 특성 향상)

  • Lee, Jeonghun;Yun, Jaehan;Byun, Hongsik
    • Membrane Journal
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    • v.27 no.3
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    • pp.255-262
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    • 2017
  • In this study, systematic integration of graphene oxide (GO) into polyacrylonitrile (PAN) nanofibers was accomplished by electrospinning to examine their mechanical properties. Exfoliated GO was initially prepared by the modified Hummer's method, and the surface of the GO was modified with an organic surfactant (e.g., cetyltrimetylammonium chloride) to improve its stability and dispersity. The overall mechanical property of the nanofiber composite membranes was highly improved. Particularly, the composite membranes with the modified GO exhibited much improved mechanical property, presumably due to the increased stability and dispersity of GO during electrospinning.

Preparation and Characterization of Lubricating Oil-based Nanofluids Containing Carbon Nanoparticles (탄소 나노소재를 이용한 윤활유 기반 나노유체의 제조 및 평가)

  • Choi, Cheol;Jung, Mi-Hee;Oh, Jae-Myung
    • Korean Journal of Materials Research
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    • v.19 no.3
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    • pp.156-162
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    • 2009
  • Lubricant-based nanofluids were prepared by dispersing carbon nanoparticles in gear oil. In this study, the effects of the particle size, shape and dispersity of the particles on the tribological properties of nanofluids were investigated. Dispersion experiments were conducted with a high-speed bead mill and an ultrasonic homogenizer, and the surfaces of the nanoparticles were simultaneously modified with several dispersants. The effective thermal conductivity of the nanofluids was measured by the transient hot-wire method, and the tribological behaviors of the nanofluids were also investigated with a disk-on-disk tribo-tester. The results of this study clearly showed that the combination of the nanoparticles, the deagglomeration process, the dispersant and the dispersion solvent is very important for the dispersity and tribological properties of nanofluids. Lubricant-based nanofluids showed relatively low thermal conductivity enhancement, but they were highly effective in decreasing the frictional heat that was generated. For nanofluids containing 0.1vol.% graphite particles in an oil lubricant, The friction coefficient in the boundary and fluid lubrication range was reduced to approximately 70% of the original value of pure lubricant.

Effects of Organosilicate Structure on Melt Intercalation of Thermoplastic Polymers (유기화제 구조가 열가소성 나노복합체의 제조에 미치는 영향)

  • 어태식;김성수;송기국;김준경
    • Polymer(Korea)
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    • v.24 no.6
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    • pp.794-801
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    • 2000
  • The effect of chain length and packing density of intercalated surfactants, annealing temperature, and annealing time on static melt intercalation of thermoplastic polymers was examined using x-ray and FTIR spectroscopy. Although melt intercalation of polymers was not successful when alkyl chains in organosilicates form a lateral monolayer structure, the type and structure of surfactants could not much affect final interlayer distances of most polymer/silicate hybrids. As annealing time increases, interlayer distance in organosilicates increases while the dispersity of the spacing between silicate layers decreases. However, the dispersity of interlayer spacing as well as interlayer distance in organosilicates increase with annealing temperature.

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A Physico-chemical Change of Dissolving Pulp by Dry Milling and Fractionation (건식분쇄와 분급에 의한 용해용 펄프의 특성변화)

  • Kim, Taeyoung;Lee, Songmin;Heo, Yongdae;Kim, Jinyoung;Joung, Yangjin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.47 no.5
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    • pp.23-32
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    • 2015
  • In this study, chemical and physical changes of dissolving pulps which have similar viscosity by dry milling and fractionation were investigated. We used two types of dissolving pulp made from wood and cotton linter fiber, respectively. Dry milling was executed by knife cutter and pulp powders were fractionated by sieve shaker into 4 grades. We analyzed fiber properties, crystallinity index, viscosity, molecular weight of pulp sheet and powders. It was found that poly-dispersity index of cotton linter pulp was smaller than that of wood pulp, meaning that cotton pulp has more narrow molecular weight distribution. It was assumed that these were related to exposure times to chemical treatment which cut cellulose chains not evenly. At least 4 times of chemical treatments for wood pulp were executed and only two times of chemical treatments for cotton linter pulp were done. After dry milling average molecular weight and crystallinity index of cotton linter pulp powders were reduced and these were related to fines content and shape of pulp powders.