• Textile Coloration and Finishing
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• v.7 no.4
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• pp.45-53
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• 1995

Natural rubber(NR)-polyacrylamide(PAAm) graft copolymers(GP)(toluene soluble GP : TSGP, water dispersible GP : WDGP) have been synthesized as coupling agents by pre-emulsification methods based on "inverse emulsion graft polymerization" technique. The polymerization was carried out at $65^{\circ}C$ using Azobisisobytyro nitrile(AIBN) as an initiator in the inverse emulsion system formed by inxing NR toluene solution with inverse emulsion of awueous AAm solution emulsified with $Tween^{\#}$ 80 in toluene. The mechanism of inverse emulsion graft copolymerization was studied on AAm conversion, % grafting, grafting efficiency, NR conversion, production ratio of TSGP and amount of GP(sum of TSGP and WDGP). The reaction has been confirmed through use of optical microscope to proceed via adsorption of emulsifier colloid particles onto the stretched NR molecule. From the analysis of the effects of various polymerization conditions on the grafting, it has also been found that the present rection system can easily yield high(over 90%) grafting efficiency and AAm conversion and relatively high(over 80%) NR conversion.onversion.

• Journal of the Korean Applied Science and Technology
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• v.27 no.2
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• pp.183-187
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• 2010

Core-Shell polymers of silicone dioxide-styrene system were prepared by sequential emulsion polymerization. In inorganic/organic Core-Shell composite particle polymerization, silicone dioxide adsorbed by surfactant sodium dioctyl sulfosuccinate (EU-DO133L) was prepared initially and then core silicone dioxide was encapsulated emulsion by sequential emulsion polymerization using styrene at the addition of potassium persulfate (KPS) as an initiator. We found that $SiO_2$ core shell of $SiO_2$/styrene structure was formed when polymerization of styrene was conducted on the surface of $SiO_2$ particles, and the concentration sodium dioctyl sulfosuccinate (EU-DO133L) was 0.5~2.0g. 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).

• Journal of Adhesion and Interface
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• v.13 no.3
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• pp.101-108
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• 2012

Narrowly dispersed poly(BMA-co-MMA) and PBMA latices (PSD : 1.002~1.008) were synthesized successfully by surfactant-free emulsion polymerization with 2,2' azobis(2-methyl-propionamidine) dihydrochloride (AIBA) and $K_2S_2O_8$ (KPS). The number average particle diameter and the number average molecule weight were found to be 160~494 nm and (1.25~7.55) ${\times}10^4$, respectively. The influences of BMA/MMA ratio, monomer and initiator concentrations, addition of DVB/EGDMA crosslink agent, and polymerization temperature on the polymerization rates and on the particle size and molecular weight were studied. The rate of polymerization increased with increasing MMA concentration in BMA/MMA weight ratio. The particle diameter as well as the polymer molecular weight could be controlled easily by controlling the BMA/MMA weight ratio, monomer concentration, AIBA and KPS concentration, and polymerization temperature.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.609-614
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• 2010

In this study, emulsion polymerizations for synthesizing acrylic pressure-sensitive adhesive(PSA) were carried out using 2-ethylhexyl acrylate(2-EHA), n-butyl acrylate(n-BA), methyl metacrylate(MMA) as fundamental monomers and acrylic acid(AAc) as a functional monomer in the presence of anionic SLS (sodium lauryl sulfate). To obtain the optimized synthetic condition in the polymerization, we analyzed the polymerization variables such as the effect of surfactant concentration and hydrophilic lipophilic values(HLB). At the same time, the final adhesive properties were also analyzed by the function of the initiator concentration and buffer concentration. In the results, the most stable emulsion was obtained at the surfactant concentrations between 3 and 5 wt%. It was also determined the effect of HLB value of nonionic surfactant and the initiator concentrations on the gel content. Stable emulsion is obtained using the surfactant having HLB value of 12.3. The rate of emulsion polymerization was increased at the initiator concentration greater than 1 wt%, but the stability of the emulsion was decreased. Finally, the effect of the buffer concentrations on the pH and the conversion of the acrylic emulsion product were experimentally measured. At the sodium bicarbonate concentration above 0.4 wt%, the buffer infulence was apparent. The buffer effect was fully acceptable at the concentrations between 0.6 and 0.8 wt% regardless of the monomer composition.

• Macromolecular Research
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• v.12 no.2
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• pp.240-245
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• 2004

Monodisperse PMMA micro spheres are prepared by means of a simple soap-free emulsion polymerization in methanol-enriched aqueous medium in a single step process. The size and uniformity of the microspheres are dependent on the polymerization temperature. In a stable system, the uniformity is improved with the polymerization time. The most uniform and stable micro spheres are obtained under mild agitation speed of 100 rpm at 70$^{\circ}C$. The monodisperse PMMA microspheres in the size range of 1.4-2.0 $\mu\textrm{m}$ having less than 5% size variation are successfully achieved with varying concentrations of monomer and initiator. As the monomer and initiator concentrations increase, the larger micro spheres with enhanced uniformity are obtained. However, the decreased amount of water induces the polydisperse PMMA particles due to the generation of secondary particles.

• Elastomers and Composites
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• v.31 no.3
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• pp.175-182
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• 1996

Polymer latices, prepared from the emulsion polymerization of vinyl monomer compounds, are widely used for many industrial applications. Included among these are uses in paints, adhesives, flocculants, and heavy-duty plastics as well as their original use in synthetic rubber compounds. The emulsion polymerization process with chemical initiator has chemical disadvantage such as removal of initiator which was left after polymerization. In this study, polystyrene latex was prepared by using ultrasonic irradiation which generate the free radical, and then it was analyzed by GPC. Reaction temperature hardly have an effect on average molecular weight. Average molecular weight is increased by increasing amount of surfactant, i.e. SDS, but polydispersity is decreased. After 90 minutes of reaction time, increase and decrease of average molecular weight Is repeated. It is proposed that monodisperse polymer is obtained by controlling ultrasonic irradiation time and surfactant concentration.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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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 Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.158-159
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• 2009

Conducting polyaniline (PAni)-titanium dioxide ($TiO_2$) nanocomposites have been synthesized by the inverted emulsion polymerization method. The resultant PAni-$TiO_2$ nanocomposites are characterized with their structural, morphological, conducting and optical properties.

• Journal of the Korean Applied Science and Technology
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• v.25 no.4
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• pp.485-494
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• 2008

The acrylic coating emulsions were prepared by the emulsion polymerization to protect the surface of steel plate from the corrosion chemicals like acid, base and salt water. MMA(methyl methacrylate), styrene, BA(butyl acrylate), and 2-HEMA(2-hydroxyethyl methacrylate) were used as monomer. KPS(potassium persulfate) and SBS(sodium bisulfite) as redox initiator and SDBS(sodium dodecylbenzene sulfonate) as emulsifier were used on the emulsion polymerization reaction. The most stable in-situ coating was obtained when 10% of MMA was added. Both particle size and quantity in emulsion were decreased as increasing the mount of SDBS. the most stable prepared coating emulsion with polyisocyanate crosslinker showed very high anticorrosion properties on the coated steel layer to salt water, whereas no significant improvement of anticorrosion property to acdic and basic condition it showed.

• Polymer(Korea)
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• v.34 no.6
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• pp.491-494
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• 2010

Colored, electrophoretic polymer nanoparticles of poly (styrene-co-divinylbenzene-co-vinyl acetate)[poly(St-co-DVB-co-VAc)] were prepared by emulsifier-free emulsion co-polymerization and reactive dyeing. The emulsifier-free emulsion polymerization of styrene, divinyl benzene and vinyl acetate was carried out at $70^{\circ}C$ for 20 hrs to obtain monodisperse polymer nanoparticles of poly(St-co-DVB-co-VAc) with an average diameter of 180~200 nm. These nanoparticles were transformed into poly(styrene-co-divinylbenzene-co-vinyl alcohol) [poly(St-co-DVB-co-VA)] nanoparticles through the saponification reaction. The poly(St-co-DVB-co-VA) nanoparticles were treated with reactive dyes to obtain the colored, monodisperse electrophoretic nanoparticles, and their morphology and surface charge were characterized by scanning electron microscopy, differential scanning calorimetry, UV/Vis absorbance and zeta-potentiometry.