• Journal of the Korean Applied Science and Technology
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• v.21 no.3
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• pp.197-203
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• 2004

Acrylic resins ($HSC_s$ : EA/EMA/2-HEMA/CLA) which contain 70% solid content were synthesized by the copolymerization of monomers (2-hydroxyethyl methacrylate, ethyl acrylate, and ethyl methacrylate) and functional monomer (caprolactone acrylate : CLA) which improves the crosslinking density and physical properties of films. The physical properties of the prepared acrylic resins (HSCs) containing CLA, are as follows : viscosity 245${\sim}$515 cps ; $M_n$ 2670${\sim}$2840 ; and conversions, 83${\sim}$91%, respectively. From the correlation of $T_g$ values, viscosities, and $M_n$ of the HSCs, it was found that viscosity and $M_n$ increased with $T_g$ value.

• Journal of the Korean Applied Science and Technology
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• v.23 no.2
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• pp.99-109
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• 2006

In order to obtain the maximum flame retardancy as well as the minimum deterioration of physical properties of PU flame-retardant coatings, chlorine and phosphorus functional groups were introduced into the pre-polymer of modified polyesters. In the first step, the tetramethylene bis(orthophosphate) (TBOP) and neohexanediol dichloroacetate (DCA-adduct) intermediates were synthesized. In the second step, 1,4-butanediol and adipic acid monomers were polymerized with the two kinds of intermediates to obtain copolymers. The modified polyesters containing chlorine and phosphorus (ATBA-10C, -20C, and -30C) were synthesized by adjusting that the content of phosphorus compound was fixed as 2wt% and the contents of chlorine compound (dichloroacetic acid) were varied as 10, 20, and 30wt%. Average molecular weight and polydispersity index of the preparation of ATBAs were decreased with increasing DCA content because of the increase in hydroxyl group that retards reaction.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.823-827
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• 2005

Barrier ribs in the plasma display panel (PDP) function to maintain the discharge space between the glass plates as well as to prevent optical crosstalk. Patterning of barrier ribs is one of unique processes for making PDP. Barrier ribs could be formed by screen-printing, sand blasting, etching, and photolithographic process. In this work photosensitive barrier rib pastes were prepared by incorporating binder polymer, solvent, functional monomers photoinitiator, and barrier rib powder of which surface was treated with fumed silica particles. Studies on the function of materials for the barrier rib paste were undertaken. After optimization of paste formulation and photolithographic process, it was applied to the photosensitive barrier rib green sheet and was found that photolithographic patterning of barrier ribs could be formed with good resolution up to $110{\mu}m$ height and $60{\mu}m$ width after sintering.

• Journal of the Korean Applied Science and Technology
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• v.22 no.4
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• pp.371-378
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• 2005

In the previous study, three kinds of monomers and the functional monomer, acetoacetoxyethyl methacrylate (AAEM), which could improve the film property and cross-linkage, were polymerzied into acrylic resin copolymers (HSA-98-20, HSA-98-0, HSA-98+20) containing 80% solid content. In this study, the high-solid coatings(HSA-98-20C, HSA-98-0C, HSA-98+20C) were prepared by the curing reaction between acrylic resins containing 80% solid content and isocyanate at room temperature. Various properties were examined for the film coated with the prepared high-solid coatings. The introduction of AAEM in the coatings enhanced the abrasion resistance and solvent resistance of coatings, which indicated the possible use of high-solid coatings for top-coating materials of automobile. The curing times measured by viscoelastic measurement were 350, 264, and 212 min for HSA-98-20C, HSA-98-0C, and HSA-98+20C, respectively. This shows that the curing times become shorter with increasing $T_g$ values.

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.68-75
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• 2001

Photopolymerization, the utilization of electromagnetic radiation(or light) as the energy source for polymerization of functional monomers, oligomers is the basis of important commercial processes with broad applicability, including photoimaging and RV curing of coatings and inks. The objective of this study is to investigate the characteristics of environmental fraternitive photopolymerization of methyl methacrylate(MMA). This work is the first step to continue further research about alkyl methacrylate. The experiment was done in aqueous solution under the influence of photo-initiator concentration(0.05-0.25mol/l), light intensity (5000-9000 ${\mu}J/cm^2$) and monomer concentration(2-6mol/l). Methyl methacrylate was polymerized to high conversion ratio using hydrogen peroxide($H_2O_2$) and the kinetics model we have obtained is as follows. $R_p=k_p[S]^{0.41}[M]^{0.62}[L]^{2.45} exp(53.64/RT$). The differential method of thermogravimetric analysis(Friedman method) was used to obtain value of activation energy on decomposition reaction. The average value of it res 45.4Kca1/mol.

• Advances in environmental research
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• v.2 no.4
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• pp.309-321
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• 2013

High AA new high capacity sorbent for preconcentration and determination of nickel in environmental samples was synthesized. The sorbent was synthesized by copolymerization of allyl glaycidyl ether / imminodiacetic acid with N,N-dimethylacrylamide as functional monomers in the presence of N,N-bismethylenacryl amid as cross linker and characterized by Fourier transform infra red spectroscopy, elemental analysis, thermogravimetric analysis and scanning electron microscopy. A recovery of 93.6% was obtained for the metal ion with 0.1 M, sulfuric acid as the eluting agent. The sorption capacity of the functionalized sorbent was 55.9 $mgg^{-1}$. The equilibrium sorption data of Ni(II) on polymeric sorbent were analyzed using Langmuir, Freundlich, Temkin and Redlich.Peterson models. Based on equilibrium adsorption data the Langmuir, Freundlich and Temkin constants were determined 0.87 (L mg-1), 25.87 ($mgg^{-1}$) $(Lmg^{-1})^{1/n}$ and 171.4 ($Jmol^{-1}$) respectively at pH 4.5 and $20^{\circ}C$.

• Macromolecular Research
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• v.16 no.6
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• pp.555-560
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• 2008

A series of hydroxyl-group containing polyimides (HPIs) were prepared in order to investigate the structure-gas permeation property relationship. Each polymer membrane had structural characteristics that varied according to the dianhydride monomers. The imidization processes were monitored using spectroscopic and thermog-ravimetric analyses. The single gas permeability of He, $H_2$, $CO_2$, $O_2$, $N_2$ and $CH_4$ were measured and compared in order to determine the effect of the polymer structure and functional -OH groups on the gas transport properties. Surprisingly, the ideal selectivity of $CO_2/CH_4$ and $H_2/CH_4$ increased with increasing level of -OH incorporation, which affected the diffusion of $H_2$ or the solubility of $CO_2$ in HPIs. For $H_2/CH_4$ separation, the difference in the diffusion coefficients of $H_2$ and $CH_4$ was the main factor for improving the performance without showing any changes in the solubility coefficients. However, the solubility coefficient of $CO_2$ in the HPIs increased at least four fold compared with the conventional polyimide membranes depending on the polymer structures. Based on these results, the polymer membranes modified with -OH groups in the polymer backbone showed favorable gas permeation and separation performance.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.143-146
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• 2002

Unsized AS-4 carbon fibers were etched by RF plasma and then coated via plasma polymerization in order to enhance adhesion to vinyl ester resin. The gases utilized for the plasma etching were Ar, $N_2 and O_2$, while the monomers used for the plasma polymerization coating were acetylene, butadiene and acrylonitrile. The conditions for the plasma etching and the plasma polymerization were optimized by measuring interfacial adhesion with vinyl ester resin via micro-droplet tests. Among the treatment conditions, the combination of Ar plasma etching and acetylene plasma polymerization provided greatly improved interfacial shear strength (IFSS) of 69MPa compared to 43MPa with as-received carbon fiber. Based on the SEM analysis of failure surface and load-displacement curve, it was assume that the failure might be occurred at the carbon fiber and plasma polymer coating. The plasma etched and plasma polymer coated carbon fibers were subjected to analysis with SEM, XPS, FT-IR or Alpha-Step, and dynamic contact angles and tensile strengths were also evaluated. Plasma polymer coatings did not change tensile strength and surface roughness of fibers, but decreased water contact angle except butadiene plasma polymer coating, possibly owing to the functional groups introduced, as evidenced by FT-IR and XPS.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2245-2250
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• 2014

A new accepter unit, 6,7-difluoro-2,3-dihexylquinoxaline, was prepared and utilized for the synthesis of the conjugated polymers containing electron donor-acceptor pair for OPVs. New series of copolymers with dioctyloxybenzodithiophene as the electron rich unit and 6,7-difluoro-2,3-dihexylquinoxaline as the electron deficient unit are synthesized. The solid films of poly[2,6-(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene)-alt-5,8-(6,7-difluoro-2,3-dihexylquinoxaline)] (PBQxF) and poly[2,6-(4,8-bis(2-ethylhexyloxy) benzo[1,2-b:4,5-b']dithiophene)-alt-5,8-(6,7-difluoro-2,3-dihexyl-5,8-di(thiophen-2-yl) quinoxaline)] (PBDTQxF) show absorption bands with maximum peaks at about 599 and 551 nm and the absorption onsets at 692 and 713 nm, corresponding to band gaps of 1.79 and 1.74 eV, respectively. The devices comprising PBQxF with $PC_{71}BM$ (1:2) showed open-circuit voltage ($V_{OC}$) of 0.64 V, short-circuit current density ($J_{SC}$) of $1.58mA/cm^2$, and fill factor (FF) of 0.39, giving power conversion efficiency (PCE) of 0.39%. To obtain absorption in the longer wavelength region, thiophene units without any alkyl group are incorporated as one of the monomers in PBDTQxF, which may result in low solubility of the polymers to lead lower efficiency.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.348-352
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• 2011

In this research, we have synthesized new pendant-type polyurethane polymers by introducing various chromophores with stilbene derivatives in the side-chain of the polymer backbone. The Stilbene monomers, N,N-bis(2-hydroxyethyl) amino-4'-cyanostilbene, N,N-bis(2-hydroxyethyl)amino-4'-methoxy stilbene, N,N-bis(2-hydroxyethyl)amino-4'-acetylstilbene, and N,N-bis(2-hydroxyethyl) amino stilbene, were synthesized by Wittig reaction. Another stilbene monomer, N,N-bis(2-hydroxyethyl)amino-4'-nitrostilbene, was synthesized by Knoevenagel condensation. By the measurement of UV-Vis absorption and Photoluminescence (PL) spectrum, we found that introduction of the electron-withdrawing group as a substituent shifts both UV-Vis and PL spectra to longer wavelength, and the introduction of the electron-donating group results in blue-shift of the spectrum. In case of polymer with $NO_2$ group as a substituent, PL is quenched.