• Macromolecular Research
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• v.14 no.5
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• pp.504-509
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• 2006

Poly(vinyl phosphate-b-styrene) (PVPP-b-PS) block copolymers were synthesized successfully from poly(vinyl alcohol-b-styrene) (PVA-b-PS) by reaction with phosphorus oxychloride and subsequent hydrolysis. The obtained block copolymers were slightly crosslinked, and were characterized by various analytical techniques. The total phosphorus content and the ratio of the differently bound phosphorus were obtained by both solid-state $^{31}P$ NMR and pH titration, but the results differed slightly. Characterization by energy dispersion X-ray analysis (EDS) or Rutherford back scattering (RBS), on the other hand, determined the total phosphorus contents, but the results were quite different from those by solid-state $^{31}P$ NMR.

• Korean Journal of Materials Research
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• v.1 no.3
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• pp.151-155
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• 1991

The kinetics of isothermal crystallization in blends of poly(ethylene oxide) (PEO) and poly(styrene-co-acrylic acid) (SAA) has been examined as a function of the blend ratio, the copolymer composition, and the crystallization temperature, based on the Avrami eauation. The Avrami exponents were mostly chose to 2, independent of the crystallization temperature. The crystallization rate of PEO in PEO/SAA blends decreased with the increase of SAA content. And also, the higher the acrylic acid content in the SAA copolymer, 7he slower the crystallization rate of PEO in the blends.

• Macromolecular Research
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• v.10 no.2
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• pp.91-96
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• 2002

To explore the effects of intramolecular interactions within the copolymer on the phase separation behavior of polymer blends, copolymers having two different types of intramolecular interactions, i.e., intramolecular repulsion and intramolecular attraction were prepared . In this study, poly(styrene-co-methylmethacrylate) (P(S-MMA)) having intramolecular repulsion caused by positive interaction between styrene and MMA and poly(styrene-co-ethyl-methacrylate) (P(S-EMA)) and poly(styrene-co-cyclohexylmethacrylate) (P(S-CHMA)) having intramolecular attraction caused by negative interaction between styrene and methacrylate were blended with tetramethyl poly-carbonate (TMPC). The phase behavior of blends was examined as a function of copolymer composition and blend composition. TMPC formed miscible blends with styrenic copolymers containing less than certain amount of methacrylate. The phase separation temperature of TMPC blends with copolymer such as P(S-MMA) and P(S-EMA), first increases with methacrylate content, goes through a maximum and then decreases just prior to the limiting content of methacrylate for miscibility, while that of TMPC blends with P(S-CHMA) always decreases. The calculated interaction energy for TMPC-P(S-EMA) pair is negative and monotonically increases with EMA content of the copolymer. Such behavior contradicted the general notion that systems with more favorable energetic interactions have higher LCST, The detailed inspection of the lattice-fluid theory related to the phase behavior was performed to explain such behavior.

• Membrane Journal
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• v.6 no.4
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• pp.273-283
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• 1996

A cation-exchange membranes were prepared by polystyrene and poly(sodium 4-styrene sulfonate). The degree of crosslinking of polystyrene membranes was controlled by DVB. At the same time, the structure of PS membranes was changed from RO to MF by varying the concentration of PSS in the casting solution. Water flux increased with PS-PSS membranes due to the sulfonate groups, and final membrane cast from the solution containing 5% of DVB and 3% of PSS showed MF structure.

• Macromolecular Research
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• v.17 no.7
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• pp.469-475
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• 2009

We investigated the feasibility of dispersion polymerization without any stabilizer, which has been considered essential for ensuring colloidal stability. By employing small amounts of a lyophilic comonomer, 4-vinyl pyridine, styrene was successfully polymerized by dispersion polymerization in aqueous alcohol without stabilizer to afford stable poly(styrene-co-4-vinyl pyridine) copolymer microspheres. The stable microspheres were produced in the 4-vinyl pyridine range of 2-15 wt% to styrene. Without 4-vinyl pyridine, severely coagulated particles were obtained, implying that the poly(4-vinyl pyridine) moiety endowed colloidal stability. The polymerization kinetics, behavior, and properties of the ultimate particles showed general features of dispersion polymerization. The study results suggest that stabilizer- tree dispersion polymerization is possible, thereby facilitating the synthesis of impurity(stabilizer)-tree polymer particles.

• Journal of the Korean Applied Science and Technology
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• v.13 no.2
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• pp.67-76
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• 1996

저분자량 ($\overline{M}=1970$)을 갖는 poly(styrene)(PS)와 poly(vinymethylether) (PVME)의 블렌드를 열산화시킬 때 PVME의 분자량 감소 속도는 높은 분자량을 갖는 PS와 PVME의 블렌드를 열산화 시킬 때의 PVME 분자량 감소 속도보다 훨씬 느리다. 열산화 과정 동안 PS의 분자량은 변화하지 않았으며 저분자량의 PS의 일부가 산화된 PVME를 분리할 때 함께 녹음을 알 수 있었다. 저분자량의 PS의 모델 화합물로써 2. 4-diphenylpentane을 합성하였고 1%，5%，10%의 모델 화합물을 PVME에 첨가하여 열산화 시켰다. 이 모델 화합물을 첨가하여 PVME의 열산화를 약간 지연시킬 수 있음을 알 수 있었다.

• Journal of the Korean Applied Science and Technology
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• v.13 no.1
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• pp.55-65
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• 1996

저 분자량($M_{w}=1970$)의 poly(styrene)(PS)와 poly(vinylmethylether)(PVME)의 블렌드를 열 산화시킬 때 저 분자량의 PS의 첨가량이 증가할수록 유도기간이 증가하며 열 산화속도는 감소함을 알 수 있었다. 열 산화과정 동안 저 분자량 PS와 PVME 블렌드는 상 분리를 보이지 않았다. 저 분자량을 갖는 PS와 PVME 블렌드에서 PVME의 산화 속도는 높은 분자량을 갖는 PS와 PVME 블렌드에서 PVME의 열 산화 속도보다 훨씬 느려짐을 보였다.

• Macromolecular Research
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• v.16 no.8
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• pp.676-681
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• 2008

The $\pi$-complex membranes of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) of two silver salts of $AgBF_4$ and $AgCF_3SO_3$ were prepared and tested for the separation of the propylene/propane mixtures. The Fourier-transform infrared (FT-IR) spectra of these complexes showed that the silver salts were dissolved in SEBS up to a silver mole fraction of 0.14, due to $\pi$-complexation between the aromatic C=C bonds of styrene blocks and silver ions. Above this solubility limit, ion pairs and high-order ionic aggregates began to form, so that silver salts were distributed unselectively in both the EB and PS blocks. The domain size of the PS blocks was enlarged up to this critical concentration with increasing silver concentration without structural transitions, as confirmed by small angle x-ray scattering (SAXS). These structural properties of the SEBS/silver salt complexes may explain the lower separation properties for propylene/propane mixtures compared to poly(styrene-b-butadiene-b-styrene)(SBS)/silver salt complex membranes.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.171-176
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• 2012

In this study, a crosslinked poly(styrene-butadiene-styrene) [SBS] block copolymers were prepared by using gamma ray irradiation method. The effects of various radiation doses on the degree of crosslinking, thermo property, and morphology of crosslinked SBS block copolymer were investigated. The degree of crosslinking of crosslinked SBS block copolymers were measured by gel-fraction and FT-IR. It was found that the degree of crosslinking of crosslinked SBS block copolymers increases with increase of the irradiation dose while the TGA result shows that the initial degradation temperature of irradiated SBS block copolymer was shifted to lower temperature with increasing irradiation dose. These results indicate that degradation reaction also occurs when SBS block copolymer is exposed to gamma ray irradiation for crosslinking reaction. The SAXS and FE-SEM results indicate that the phase separation of the styrene block and butadiene block was reduced with increasing irradiation dose.

• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.285-293
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• 2001

To improve the vulnerable point and the mechanical property of the existing lightweight foamed concrete, this study was intend to manufacture the lightweight foamed concrete with wasted expanded poly-styrene, examinate and analyze the mechanical property of its. The experiment was being processed with mixing the wasted expanded poly-styrene maximum 40 % by stages and which was mainly basis on the practical mixture. The results of the experiment are following. The flow value is most affected by the mixtured rate of the wasted expanded poly-styrene. The more the mixtured ratio, the less the flow value and the more the more the unit quantity of cement and the W/C, the more the flow value. The apparent specific gravity indicated 0.31∼0.54 and which is seemed to be mainly included in the 0.4 degree and 0.5 degree that are regulated in the KS F 4039. The more the mixtured wasted poly-styrene ratio, the less the apparent specific gravity. The absorbing ratio which was depend on the mixture condition indicated 11 ∼46% and the more the mixtured ratio of the wasted expanded poly-styrene, the less the absorbing ratio remarkably. The compressive strength of the lightweight foamed concrete had a tendency to increase as the mixtured ratio of the wasted poly-styrene, the ratio quantity of cement and the apparent specific gravity increasing but as the ratio of bubble decreasing. The W/C affected little.