• Elastomers and Composites
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• 제43권4호
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• pp.221-229
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• 2008

Starch as matrix polymer was used to do graft copolymerization with 2-ethylhexylacrylate, methyl methacrylate and acrylic acid. The polymerization was carried out by radical emulsion polymerization with increasing contents of starch. When 0.174% of $\alpha$-amylase as enzyme for starch was added, it was found that it made the best stable emulsion. The glass transion temperature of the polymerized material was increased with starch contents. The particle size and viscosity of the emulsion increased with starch contents due to the increased hydroxy group. Peel strength also increased with contents of starch because the enhanced hydroxy group caused to increase affinity between substrate surface and polymer materials. However, the initial tackiness decreased with starch contents owing to film hardness by higher glass transion temperature.

• Polymer(Korea)
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• 제36권1호
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• pp.65-70
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• 2012

Glycidyl methacrylate (GMA) was used to introduce epoxy groups on the surface of polypropylene (PP) plate, used as a substrate, through plasma-induced graft copolymerization. Emulsion polymerization was applied for graft copolymerization of GMA and was compared with conventional solution polymerization to confirm its effect. Plasma treatment conditions under one atmospheric pressure were fixed as follows; the RF power of 200 W, the treatment time of 30 sec, the Ar gas flow rate of 6 LPM, and the exposure time of treated PP samples in air of 5 min. For graft-copolymerization, GMA concentration, reaction temperature, and reaction time was optimized to maximize the grafting degree of GMA. The maximum grafting degree of GMA was obtained at the condition of 12%-GMA concentration, $90^{\circ}C$ reaction temperature, and 5 hr-reaction time. Analysis results supported that the emulsion polymerization was more effective than the solution polymerization for grafting more GMAs on the surface of PP plate under the same reaction conditions.

• Polymer(Korea)
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• 제32권2호
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• pp.95-102
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• 2008

The $\alpha$,$omega$-diacrylate poly(dimethylsiloxane) (DA-PDMS) containing vinyl ester of versatic acid/vinyl acetate (Veova-10/VAc) was prepared by emulsion copolymerization of (DA-PDMS), Veova-10 (with VAc), and auxiliary agents at $85^{\circ}C$ in the presence of ammonium peroxodisulfate (APS) as an initiator. Sodium dodecyl sulfate (SDS) and nonylphenol ethylene oxide-40 units (NP-40) were used as anionic and nonionic emulsifiers, respectively. The resulting copolymers were characterized by using Fourier transform infrared spectroscopy (FT-IR). Thermal properties of the copolymers were studied by using thermogravimetric analysis(TGA) and differential scanning calorimetry (DSC). The morphology of copolymers was also investigated by scanning electron microscopy (SEM) and then the effects of variables such as temperature, agitation speed, surfactant kinds, molecular weights, initiator, and DA-PDMS concentrations on the properties of the silicone-containing Veova-10/VAc emulsions were examined. The calculation of monomer conversion versus time histories indicates that by increasing the DA-PDMS concentration the polymerization rate and the number of polymer particles decrease, respectively.

• Journal of the Korean Society of Clothing and Textiles
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• 제15권3호
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• pp.271-280
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• 1991

Emulsion graft copolymerization of MMA onto cotton fiber using Ce(IV) salt as an initiator was carried out. Graft yield and graft efficiency were observed according to the kinds and concentrations of emulsifier and polymerization conditions. The physical properties of MMA grafted cotton fabric were investigated. The results of this study were as follows: 1. The heighest graft yield of emulsion graft polymerization occurred at the concentration below cmc of emulsifier, which was different from emulsion polymerization. Nonionic sur- factant as an emulsifier was more effective than anionic one. 2. The highest graft yield was obtained at the initiator concentration $1{\times}10^{-2}mol/l$. The viscometric molecular weight of PMMA was in the order of 106. 3. As reaction time increased, the graft yield increased but the graft efficiency decreased. 4. Elevation of reaction temperature resulted in increase of graft yield. The apparent activation energy of MMA graft polymerization was 4.72 Kcal/mol. 5. Physical properties of MMA grafted cotton fabric varied with increase of grafting. Thickness and stiffness showed a noticeable increase, whereas tensile strength and elongation was slightly increased. Crease recovery increased as the graft yield increase up to $50\%$ and decreased thereafter.

• Journal of Adhesion and Interface
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• 제15권3호
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• pp.93-99
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• 2014

Monodisperse poly[styrene-co-(COPS-I)] latices in the size range of 165~550nm were successfully prepared by soap-free emulsion polymerization with various polymerization conditions (Styrene, COPS-I, KPS, DVB concentrations and polymerization temperature). In general, the COPS-I and KPS, DVB concentrations and polymerization temperature were closely related to the polymerization rate and the number of particles, molecular weight, and zeta potential. The polymerization rate and zeta potential increased, but molecular weight decreased, with increasing in the number of particles.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3303-3306
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• 2014

A facile and effective approach has been developed to prepare hybrid hollow microspheres, via consecutive processes of pickering mini-emulsion polymerization for core-shell formation, and calcination of the sacrificial core. The resulting hollow composite particles have mono-layered shells. The morphology and size characteristics of synthesized composite particles were investigated, using dynamic light scattering (DLS) and scanning electron microscopy (SEM) measurements.

• Proceedings of the Korean Fiber Society Conference
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• 한국섬유공학회 1994년도 춘계학술발표회 프로그램 및 초록
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• pp.95-95
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• 1994

• Journal of Adhesion and Interface
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• 제13권2호
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• pp.64-72
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• 2012

Vinyl acetate/alkyl acrylate copolymers were prepared by water-born emulsion copolymerization according to the compositional change of vinyl acetate and various alkyl acrylates such as methyl acrylate (MA), ethyl acrylate (EA), and n-butyl acrylate (BA). Ammonium persulfate (APS) was used as an initiator and poly(vinyl alcohol) (PVA) was used as a protective colloid. The significant result was described as follows. The activation energy determined by an isothermal analysis in the temperature region between $100{\sim}200^{\circ}C$ of the copolymer had the order of PVAc/PMA > PVAc/PEA > PVAc/PBA. The peel strengths before and after the plasma treatment were the order of PVAc/PMA > PVAc/PEA > PVAc/PBA.

• Polymer(Korea)
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• 제33권3호
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• pp.230-236
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• 2009

Water soluble vinyl acetate/alkyl methacrylate copolymers were prepared by the emulsion copolymerization of vinyl acetate and various methacrylates such as methyl methacrylate (MMA) and ethyl methacrylate (EMA). Potassium persulfate (KPS) and ammonium persulfate (APS) were used as an initiator. Poly (vinyl alcohol) (PVA) was used as a protective colloid. The drying characteristics of the prepared poly(vinyl acetate-co-methyl methacrylate) (PVAc/PMMA), poly(vinyl acetate-co-ethyl methacrylate) (PVAc/PEMA) were studied using moisture meter at the temperature between 100 and $200^{\circ}C$. The significant results are described as follows. The activation energy of the isothermal drying process of the copolymers has the order of PVAc/PMMA> PVAc/PEMA> PVAc.

• Polymer(Korea)
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• 제27권6호
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• pp.596-602
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• 2003

A Polymeric emulsifier was synthesized by solution polymerization with 2-ethylhexyl acrylate, n-butyl acrylate, and acrylic acid. A series of polymeric emulsifier have been used in the emulsion copolymerization of 2-ethylhexyl actryacrylate and n-butyl acrylate. The size of the synthesized latex particles was around 145 nm and its distribution was very narrow. Emulsion with polymeric emusifier showed no coagulum after 7 cycles of freeze-thaw test, while the emulsion with traditional emulsifier exhibited coagulum after 2 cycles. The adhesion tests showed that the initial tackiness and peel strength decreased as the molecular weight and acrylic acid content of polymeric emulsifier increased, whereas the holding power increased.