• Macromolecular Research
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• v.11 no.6
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• pp.418-424
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• 2003

Exfoliated poly(methyl methacrylate-co-styrene) [P(MMA-co-ST)]/silicate nanocomposites were synthesized through a multistep emulsion polymerization. The methyl methacrylate monomers were polymerized first and then the styrene monomers were polymerized. The nanocomposites had core-shell structures consisting of PMMA (core) and PS (shell); these structures were confirmed by $^1$H NMR spectroscopy and TEM, respectively. P(MMA-co-ST) copolymers showed two molecular weight profiles and two glass transition temperatures (T$_{g}$) in GPC and DMA measurements. At 30 $^{\circ}C$, the nanocomposites exhibited 83 and 91 % increases in their storage moduli relative to the neat copolymer because the silicate layers were dispersed uniformly in the polymer matrix.x.

• The Korean Journal of Rheology
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• v.10 no.4
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• pp.247-255
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• 1998

The morphological changes during melt compounding of ternary blends containing various combinations of acrylonitrile-butadiene-styrene(ABS), methyl methacrylate-butadiene-ethyl acrylate(MBE), styrene-acrylonitrile(SAM) copolymers, and poly(methyl methacrylate)(PMMA) as dispersed components in a fixed matrix of polycarbonate(PC) have been investigated. Depending on the composition of the blend, MBE particles and PMMA phase appear to locate at the PC-SAN interface under the influence of interfacial tensions and motion induced coalescence. The interfacial viscosity is found to be a critical factor that affects the amount of coalescence.

• Journal of the Korean Chemical Society
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• v.24 no.3
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• pp.259-265
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• 1980

Poly (styrene-b-methyl methacrylate) (PS-b-PMMA) was synthesized by free radical telomerization: the telomerization of styrene with $CCI_4$ by using AIBN as initiator followed by a second telomerization of methyl methacrylate using $CCI_3$ end group of the resulting polymer as the macrotelogen, with AIBN initiation, gave the styrene-methyl methacrylate block copolymer. The effects of the concentration of the macrotelogen, the concentration of monomer, the molecular weight of the macrotelogen, the reaction temperature and the concentration of the solvent on the formation of the block copolymer were investigated. Block copolymers containing up to 10 weight percent PMMA were obtained by adjusting the reaction conditions.

• Macromolecular Research
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• v.14 no.5
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• pp.539-544
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• 2006

2-Furancarboxaldehyde-2-pyridinylhydrazone (FPH) and 5-methyl-2-furancarboxaldehyde-2-pyridinylhydrazone (MFPH) were synthesized and used as tridentate ligands of copper (I) bromide for the atom transfer radical polymerization of methyl methacrylate (MMA) and styrene. The polymerization of methyl methacrylate achieved high conversion and yielded polymers with a good control of molecular weight and low polydispersity (PDI=1.33). Higher PDI were observed in the polymerization of styrene. Using 1-phenyl ethylbromide (PEBr) and ethyl 2-bromoisobutyrate (EBiB) as model compounds for the polymeric chain ends, the activation rate constants of the new catalytic systems were measured. These results were correlated with the polymerization results and compared with another catalytic system previously reported.

• Elastomers and Composites
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• v.24 no.1
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• pp.11-18
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• 1989

The thermal degradation of Poly(methyl methacrylate) (PMMA) and poly(acrylonitrile butadiene styrene)(ABS) terpolymer as well as their mixtures were carried out using the thermogravimetry and differential scanning calorimetry(DSC) in the stream of nitrogen and air with 50 ml/min at the various heating rate from 4 to $20^{\circ}C/min$ and temperature from 200 to $300^{\circ}C$ The values of activation energies of thermal degradation determined by TG and DSC in the various PMMA/ABS mixtures were $34{\sim}58Kcal/mol,\;35{\sim}54Kcal/mol$ in the stream of nitrogen. The values of activation energy of ABS20% mixture was appeared high in camparison with addition rule. According to increasing the composition of ABS, the temperatures of glass transition and initial decomposition temperature were increased. PMMA/ABS mixtures by the analysis of infrared spectrophotometer were decomposed by main chain scission in the stream of nitrogen.

• 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.

• Journal of the Korean Chemical Society
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• v.13 no.4
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• pp.373-377
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• 1969

In order to determine the monomer reactivity ratio in copolymerization of acrolein, the copolymerization of acrolein with styrene, methyl methacrylate and vinyl acetate respectively was studied. The Q and e value of acrolein in each copolymerization were also calculated from those of monomer reactivity ratios, but the calculated values were slightly different from each other. The Q and e of acrolein for the system of acrolein-styrene copolymerization were Q = O.64 and e = O.62 respectively. Relations among the Q and e value, the composition and structure of copolymers and the mean sequence length in copolymerization were also discussed for acrolein copolymers.

• Polymer(Korea)
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• v.39 no.2
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• pp.191-199
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• 2015

In order to improve the low impact resistance of polystyrene without harming its transparency the styrene monomer was copolymerized with transparent butyl acrylate (BA), and methylmethacrylate (MMA) to obtained a poly(styrene-co-butylacrylate) P(SM-co-BA) and a terpolymer copolymer P(SM-co-BA-co-MMA). The polymers were then cross-linked with the aid of a cross-linking agent dicumylperoxide (DCP), and their mechanical and optical properties were tested. It was found that the contents of monomers and DCP affect the mechanical, thermal, and optical properties of the polymers. An increase in BA contents in P(SM-co-BA) and P(SM-BA-MMA) improved the mechanical strength, but the optical properties remained the same with some exception for P(SM-co-BA). An increase in the DCP contents improved the mechanical but found losses in the optical properties.

• Macromolecular Research
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• v.17 no.4
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• pp.218-220
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• 2009

• Elastomers and Composites
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• v.37 no.1
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• pp.21-30
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• 2002

Core-shell polymers of methyl methacrylate/styrene pair were prepared by sequential emulsion polymerization in the presence of sodium dodecyl benzene sulfonate(SDBS) as an emulsifier using ammonium persulfate(APS) as an initiator. 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, where as polymer blonds or copolymers show a combined properties from the physical properties or two homopolymers. This unique behavior of core-shell composite latex can be used in many industrial fields. However, in preparation of core-shell composite latex, several unexpected phenomina are observed, such as, particle coagulation, low degree of polymerization, and formation of new particles during shell polymerization. To solve the disadvantages, we studied the effects of surfactant concentrations, initiator concentrations, and reaction temperature on the tore-shell structure or PMMA/PSt and PSt/PMMA. Particle size and particle size 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 transition temperature($T_g$) was also measured by using differential scanning calorimeter. To identify the core-shell structure, pH of the composite latex solutions were measured.