• Title, Summary, Keyword: core-shell

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Manufacture of PMMA/PBA and PBA/PMMA core Shell Composite Particles - Effect of emulsifier - (PMMA/PBA와 PBA/PMMA Core Shell 복합입자의 제조 - 유화제의 영향 -)

  • Seul, Soo Duk
    • Journal of Adhesion and Interface
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    • v.11 no.3
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    • pp.112-119
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    • 2010
  • Poly(methyl methacrylate)/poly(butyl acrylate) PMMA/PBA core-shell composite particles were prepared by the emulsion polymerization of MMA and BA in the presence of different concentration of sodium dodecyl benzene sulfonate (SDBS). The following conclusions are drawn from the measured conversion and particle size distribution, morphology, average molecular weight distribution, observation of film formation and particle formation, glass transition temperature and physical properties of polymerized core-shell composition particles for using adhesive binder. When the concentration of 0.03 wt% surfactant, the conversions of PMMA and PBA core polymerization are excellent as 95.8% for PMMA core and 92.3% for PBA core. Core-shell composite particles are obtained 90.0% for PMMA/PBA core-shell composite particles and 89.0% for PMMA/PBA core-shell composite particles. It is considered that the core and shell particles are polymerized to be confirmed FT-IR spectra and average molecular weight measured with a GPC, formation of the composite particles is confirmed by the film formation from normal temperature, and composition of inside and outside of the composite particle is confirmed by TEM photograph. The synthesized polymer has two glass transition temperatures, suggesting that the polymer is composed of core polymer and shell polymer unlike general copolymers. It is considered that each core-shell composite particle can be used as a high functionality adhesion binder by the measurement of tensile strength and elongation.

TCC behavior of a shell phase in core/shell structure formed in Y-doped BaTiO3: an individual observation (Yttrium이 첨가된 BaTiO3에서 형성된 core/shell 구조에서 shell의 TCC 거동: 독립적 관찰)

  • Jeon, Sang-Chae
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.30 no.3
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    • pp.110-116
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    • 2020
  • Grains in the BaTiO3, which is used for a dielectric layer in MLCC(Multi-Layer Ceramic Capacitor) are necessary to form core/shell structure for a stable TCC(Temperature Coefficient of Capacitance) behavior. The shell property has been deduced from the whole TCC behavior of core/shell structure due to its tiny size, ~ few ㎛. This study demonstrates the individual TCC behavior of the shell phase measured by micro-contact measurement in a temperature range between 35 and 135℃. Pt electrode pairs deposited on an enlarged core/shell structure in a diffusion couple sample made the measurement possible. As a result, the DPT (Diffusion Phase Transition) behavior of the shell phase was revealed as a different TCC behavior from that of the core: a broad peak with Tm at 65℃. This would be also useful experimental data for a modelling that depicts dielectric-temperature behavior of core/shell structure.

Polymerization and Effect of Organic/Organic Core Shell Binder (Organic/organic Core Shell 바인더의 중합과 처리영향)

  • Sim, Dong-Hyun;Ban, Ji-Eun;Kim, Min-Sung;Seul, Soo-Duk
    • Polymer(Korea)
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    • v.32 no.5
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    • pp.470-477
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    • 2008
  • Core shell binder of organic/organic pair that has two different properties within a particle were prepared by a step emulsion polymerization of methacrylate (MMA), styrene (St), ethyl acrylate (EA), butyl acrylate (BA), and 2-HEMA by using an water soluble initiator(APS) in the presence of an anionic surfactant (SDBS). Unwoven tensile strength of the core shell binder after processing and measuring the PSt/PMMA/2-HEM core shell with the binder is a value represents the highest was $10.75\;kg_f$/2.5cm, elongation measurements PEA/PBA core shell binder showed the highest value was 120.00%. In conclusion, using the core shell binders were able to control the mechanical properties such as tensile strength and elongation.

Manufacture of Core-Shell Composite Polymer Materials for Nonwoven binder (부직포 바인더용 Core-Shell 복합소재의 제조)

  • Lee, Sun Ryong;Lim, Jae Keel;Seul, Soo Duk
    • Journal of Adhesion and Interface
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    • v.3 no.4
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    • pp.27-36
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    • 2002
  • The organic/organic core-shell composite polymer for nonwomen binder were synthesized by stage polymerization of methyl methacrylate and styrene with ammonium persulfate after preparing monomer pre-emulsion in the presence of anionic surfactant. We study the effect of initiator concentration, $0.79{\times}10^{-3}{\sim}3.16{\times}10^{-3}mol/L$ for core polymer, $2.0{\times}10^{-4}{\sim}8.0{\times}10^{-4}mol/L$ for shell polymer, sulfactant concentration, $1.45{\times}10^{-5}{\sim}4.15{\times}10^{-5}mol/L$ for core polymer, $0.73{\times}10^{-5}{\sim}2.91{\times}10^{-5}mol/L$ for shell polymer on core-shell structure of polymethyl methacrylate/polystyrene and polystyrene/polymethyl methacrylate. Emulsion stability was major test method, particle size and particle size distribution were measured using particle size analyzer and the morphology of the core-shell composite polymer was determined using transmission electron microscope, glass temperature was also measured using differential scanning calorimeter.

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A Study of Synthesis and Property of $CaCO_3$/Organic Core-Shell Particle (탄산칼슘 /유기계 Core-Shell 입자의 제조와 물성에 관한 연구)

  • Seul, Soo-Duk
    • Polymer(Korea)
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    • v.34 no.1
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    • pp.38-44
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    • 2010
  • Core-shell particles of inorganic/organic pair were synthesized from $CaCO_3$ absorbed sodium dodecyl benzene sulfonate(SDBS) surfactant. Shell components were synthesized by sequential emulsion polymerization. Various monomers were used as shell components such as methyl methacrylate(MMA), ethyl acrylate(EA), butyl acrylate(BA), and styrene(St). Ammonium persulfate(APS) was used as an initiator and 2-ethylhexyl acylate(2-EHA) was used as a functional monomer, In the $CaCO_3$/organic core-shell particle polymerization, $CaCO_3$ absorbed surfactant SDBS of 0.5 wt% was prepared first and then core $CaCO_3$ was encapsulated by emulsion polymerization. 0.1 wt% of APS was added sequentially to minimize the formation of new monomer particle during shell polymerization. The structure of inorganic/organic core-shell particles were characterized by measuring the decomposition degree of $CaCO_3$ using HCl solution, thermogravimetric analyzer, scanning electron microscope, and transmission electron microscope.

A Study on the Effect of Surfactant in Synthesizing Titanium Dioxide/Acrylate Core-Shell Polymer ($TiO_2$/Acrylate 코어-셀 합성에서 계면활성제의 영향에 관한 연구)

  • Kim, Duck-Sool;Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.27 no.1
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    • pp.56-60
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    • 2010
  • Titanium dioxide particles are used as photocatalysts, sensors, adsorbents and catalyst. Core-shell polymers of inorganic/organic pair, which have both core and shell component, were synthesized by sequential emulsion polymerization using Acrylate as a shell monomer and potassium persulfate (KPS) as an initiator. We found that when Acrylate core prepared by adding 0.5~2.0 wt% EU-S133D, Titanium dioxide / Acrylate core-shell polymerization was carried out on the surface of Titanium dioxide particle without forming the new Titanium dioxide particle during acrylate shell polymerized in the inorganic/organic core-shell polymer preparation. The structure of core-shell polymer were investigated by measuring to the thermal decomposition of polymer composite using thermogravimetric analyzer(TGA) and morphology of latex by scanning electron microscope(SEM).

The Effect of Anionic Surfactants in Synthesizing Silicone Dioxide/Acrylate Core-Shell Polymer (이산화규소/아크릴계 유기물의 코어-셀 합성에서 음이온 계면활성제의 영향)

  • Kim, Duck-Sool;Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.26 no.2
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    • pp.199-204
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    • 2009
  • Silicone dioxide absorbed polyoxyethylene alkylether sulfate (EU-S133D) surfactant was prepared. Core-shell polymers of inorganic/organic pair, which have both core and shell component, were synthesized by sequential emulsion polymerization using Acrylate as a shell monomer and potassium persulfate (KPS) as an initiator. We found that when Acrylate core prepared by adding 2.0 wt% EU-S133D, silicone dioxide/Acrylate core-shell polymerization was carried out on the surface of silicone dioxide particle without forming the new silicone dioxide particle during acrylate shell polymerization in the inorganic/organic core-shell polymer preparation. The structure of core-shell polymer were investigated by measuring to the thermal decomposition of polymer composite using thermogravimetric analyzer and morphology of latex by scanning electron microscope(SEM).

Plasma Treatment Effect of Organic/Organic Core-Shell Acrylic Adhesive Binder (II) (Organic/Organic Core-Shell 아크릴 접착바인더의 플라즈마 처리영향 (II))

  • Seul, Soo-Duk
    • Polymer(Korea)
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    • v.34 no.2
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    • pp.89-96
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    • 2010
  • Adhesive binders with core-shell structure of organic/organic pair were prepared by emulsion polymerization of acrylic monomers, such as methyl methacrylate(MMA), ethyl acrylate(EA), n-butyl acrylate(BA), and styrene(St). Ammonium persulfate (APS) was used as an water soluble initiator in the presence of an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS). Non-woven fabric and leather were impregnated with the adhesive binder. The surface of the impregnated fabric and leather were treated with plasma technique and then kinetics analysis and mechanical properties were measured. The conversions of the polymerization of core-shell binder (MMA/EA, MMA/BA) were greater than 90%. When the core-shell binder was prepared at equimolar conditions, the increasing effect of the core-shell binder on the state peel strength of the impregnated and plasma-treated non-woven/non-woven fabric has the order of MMA/St, EA/BA, BA/MMA, EA/St, and EA/MMA. When the core-shell binder was prepared at non-equimolar conditions, the increasing effect of the core-shell binder on the state peel strength of the non-woven fabric/leather has the order of MMA/BA, BA/EA, MMA/EA, St/MMA, and EA/St.

A Study on the Flexural Property of Glass Fiber Filled Coextruded Wood Plastic Composites (유리섬유가 충전된 공압출 목재.플라스틱 복합재의 굽힘 특성에 관한 연구)

  • Kim, Birm-June
    • Journal of the Korea Furniture Society
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    • v.24 no.4
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    • pp.379-388
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    • 2013
  • In this study, the effect of various glass fiber (GF) contents in a shell layer and shell thickness changes on the flexural property of coextruded wood plastic composites (WPCs) in combination with three core systems (weak, moderate, and strong) was investigated. GF behaved as an effective reinforcement for the whole coextruded WPCs and GF alignments in the shell layer played an important role in determining the flexural property of the coextruded WPCs. At a given shell thickness, the flexural property of the whole coextruded WPCs was improved with the increase of GF content in shell. For core quality, when the core is weak, increase of GF content in shell led to improved flexural property of the whole composites and increase of shell thickness helped it. On the other hand, when the core is strong, the flexural property of the whole composites showed reduced features at low GF content in shell and increase of shell thickness aggravated it. This approach provides a method for optimizing performance of the coextruded WPCs with various combinations of core-shell structure and properties.

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Preparation of Methyl Methacrylate-Styrene System Core-Shell Latex by Emulsion Polymerization (유화중합에 의한 Methyl Methacrylate-Styrene계 Core-Shell 라텍스 입자 제조에 관한 연구)

  • Kim, Nam-Seok;Kim, Duck-Sool;Lee, Seok-Hee;Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.22 no.2
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    • pp.96-105
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    • 2005
  • Core-shell polymers of methyl methacrylate-styrene system were prepared by sequential emulsion polymerization in the presence of sodium dodecyl benzene sulfonate(SDBS) as an emulsifier using ammonium persulfate(APS) in an initiator and the characteristics of these core-shell polymers were evaluated. Core-shell composite latex has the both properties of core and shell components in a particle, whereas polymer blends or copolymers show a combined physical properties of two homopolymers. This unique behavior of core-shell composite latex can be used in various industrial fields. However, in preparation of core-shell composite latex, several unexpected matters are observed, for examples, particle coagulation, low degree of polymerization, and formation of new particles during shell polymerization. To solve this matters, we study the effects of surfactant concentrations, initiator concentrations, and reaction temperature on the core-shell structure of PMMA-PSt and PSt-PMMA. Particle size and particles distribution were measured by using particle size analyzer, and the morphology of the core-shell composite latex was observed by using transmission electron microscope. Glass temperature was also measured by using differential scanning calorimeter. To identify the core-shell structure, pH of the composite latex solutions was measured.