• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.300-305
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• 1998

Kinetics of termonomer emulsion polymerization during interval II (i.e, after completion of latex particle formation) were studied through pseudo-homopolymerization (PHP) method. Extended Smith-Ewart equation and equation of instantaneous polymer composition are respectively reduced to the corresponding equation for homopolymerization by defining average rate constants. Average number of radicals per particle and instantaneous polymer compositions were respectively predicted by varying termonomer composition within latex particles for systems containing no more than one growing radical per particle. Styrene-Methyl methacrylate-Acrylonitrile (SMA) system was used for model calculation.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.468-473
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• 2003

유화중합은 물을 용매로 사용하기 때문에 화재와 폭발의 위험성이 없고 환경문제가 없으며 원료 원가 면에서 저렴한 특징이 있기 때문에 수요가 매년 증가하고 있는 실정이다. 이 같은 장점을 지닌 유화중합은 물을 분산매로 폴리머를 제조하는 유용한 기술이지만 유화제, 이온성의 개시제 등과 같이 폴리머 본래의 성질을 저하시키며 물에 잘 용해되는 성분을 수반한다. 따라서 이러한 기존 유화중합법의 단점을 보완한 새로운 에멀젼 라텍스 제조기술로서, 유화제 대신에 폴리비닐알콜과 같은 보호폴로이드 또는 유기 과산화물을 사용하는 무유화제 제조기법에 대한 연구가 이루어지고, 이와 같이 제조된 에멀젼 라텍스는 기존 공정에 의해 제조된 제품에 비해 내수성과 건조된 필름의 인장 강도 및 여러 매트릭스에 대한 부착력이 향상된다. 그러나 이들 방법으로 제조된 폴리머도 복합 물성이 요구되는 분야에는 한계가 있어 복합 라텍스 제조에 대한 새로운 연구가 최근에 많이 되고 있다.(중략)

• Elastomers and Composites
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• v.43 no.4
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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.

• Elastomers and Composites
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• v.33 no.4
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• pp.231-237
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• 1998

In order to investigate the physical properties of rubber blend compound, this experiment was carried out on the cure rate, loss tangent, reinforcement and abrasion properties of S-SBR (solution styrene-butadiene rubber) blends containing silane coupled silica and E-SBR (emulsion styrene-butadiene rubber) blends containing carbon black as a model compound. E-SBR blend showed the highest total bound rubber(TBR), while S-SBR blends showed constant TBR level regardless of rubber type. Rapid cure rate was achieved when the styrene and vinyl content of rubber microstructure decreased and TBR content of rubber compounds increased. The modulus as the index of rubber reinforcement showed the linear relation with TBR content. The large amount of PICO loss was observed when the styrene and vinyl content of rubber microstructure increased, while the small amount of PICO loss was observed when the ratio of bu-tadiene increased in the S-SBR blends with silane copuled silica. The high loss tangent at $0^{\circ}C$, the low loss tangent at $60^{\circ}C$, and the large difference of loss tangent were shown in the S-SBR blends with high styrene content compared to E-SBR blend.

• 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.

• 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.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.10a
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• pp.148-153
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• 2003

고분자 물질은 유기용제를 사용하여 제조되는 경우가 일반적이다. 이들 중에서 용제형 아크릴계 고분자는 점착강도, 내습성, 내수성 그리고 내열성 등이 우수하여 페인트, 접ㆍ점착제, 섬유 등의 산업전반에 이용되고 있으나 용제사용에 따른 화재의 위험성과 환경적인 문제점 때문에 규제의 대상이 되고 있다. 이러한 위험성과 환경문제점은 유화중합법에 의해 고분자물질을 제조함으로써 해결되며, 그 중에서 단계 유화중합법은 다른 중합법에 비해 온도조절이 용이하며, 반응속도와 분자량을 조절할 수 있다는 장점 때문에 latex 공업이나 고분자 blending 기술면에서 많이 이용되고 있는 실정이다.(중략)

• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.470-475
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• 2009

To study the optimal synthesis conditions of aqueous acrylic adhesive using emulsion polymerization, the effects of monomer, surfactant and initiator on the adhesive properties, such as conversion rate, particle size, peel strength, and glass transition temperature, were investigated. 2-EHA, n-BA and MMA were used as main monomers, 2-HEMA and AAc as functional monomers, SLS as surfactant and APS as initiator, respectively. The conversion rate was over 95% at 3.75% surfactant(SLS/monomer), 0.612% initiator(APS/monomer) and $82^{\circ}C$ reaction temperature. When the excess amount of surfactant or initiator was used, the peel strength represented decreasing tendency. The maximum conversion rate and peel strength were obtained at 65% 2-EHA/monomer, 20% BA/monomer, and 10% MMA/monomer.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.294-299
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• 1998

To prove pseudo-homopolymerization(PHP) method indirectly for general system which includes more than one growing radicals per particle, Mayo-Lewis equation of bulk copolymer system was derived form probability equation about instantaneous copolymer composition of emulsion copolymer system during interval II. From Extended Smith-Ewart equation proposed by Ballard et al. in emulsion copolymerization, exact solution was obtained for 0-1 system (i.e., the system containing no more than one growing radical per particle). From the exact solution, average number of radicals per particle and instantaneous copolymer composition were predicted to reach the steady state which a few minutes. So the reliability of this approximation method could by proved directly for 0-1 system. Styrene-butadiene(St-Bu) and Styrene-methyl methacrylate (St-MMA) system were used for model calculations.

• Polymer(Korea)
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• v.27 no.6
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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.