• 한국잠사곤충학회지
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• 제34권2호
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• pp.32-40
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• 1992

반응개시제로 potassium persulfate를 사용한 MAA 가공견섬유에 대하여 열분석, IR spectrum, 아미노산 분석, 전자현미경 등의 기기분석을 통하여 반응 mechanism에 대하여 구명하고자 하였다. IR spectroscopy 분석에서 가공견섬유의 peak은 미가공견섬유와 MAA polymer의 peak을 모두 가지고 있으며, 특이한 peak의 변화는 관찰할 수 없었다. 아미노산 분석에서는 vinyl monomer가 graft된다는 종래의 특정 아미노산의 함량에 있어서, 가공률의 증가에 따른 변화를 관찰할 수 없었으며, MAA 가공견섬유의 중합 mechanism은 styrene 및 MMA의 graft 가공에서와는 일치하지 않는 것으로 나타났는데, 이는 monomer, 개시제, 반응조건에 따라 반응에 관여하는 아미노산이 다른 것으로 추정된다. SEM 관찰에서는 가공률이 낮은 경우의 섬유표면은 미가공견섬유의 표면과 그 차이를 인정할 수 없었으나, 가공률이 증가함에 따라 섬유표면에 섬유축방향으로 줄무늬가 형성되는 것을 관찰할 수 있었다. 이상의 관찰과 앞서 발표한 열분석 결과를 종합하면, potassium persulfate를 반응개시제로한 MAA 가공견의 중합기구에 대해서는 DSC나 IR spectroscopy에 의한 관찰로는 중합기구를 정성정량적으로 분석하기는 힘든 것으로 나타났으며, 아미노산 분석결과로부터 이미 styrene이나 MMA 가공견의 grafting site로 알려 져 있는 Gly, Ala, Ser, Tyr, Thr, Met 및 염기성 아미노산 등의 특정 아미노산에 선택적으로 graft되는 경향을 인정할 수 없으므로 이는 graft 중합에 의해 결합되는 것이라기보다 단지 섬유내부중합에 의해 polymer가 섬유내부에 형성되는 것으로 추정된다. 현미경관찰에서도 polymer는 주로 섬유내에 형성되며, 무게증가율이 큰 경우에는 섬유의 표면에 MAA에 의한 특징적인 줄무늬의 형성을 관찰할 수 있었다.

• Transactions on Control, Automation and Systems Engineering
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• 제4권1호
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• pp.62-74
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• 2002

The tracking of a reference temperature trajectory in a polymerization batch reactor is a common problem and has critical importance because the quality control of a batch reactor is usually achieved by implementing the trajectory precisely. In this study, only energy balances around a reactor are considered as a design model for control synthesis, and material balances describing concentration variations of involved components are treated as unknown disturbances, of which the effects appear as time-varying parameters in the design model. For the synthesis of a tracking controller, a method combining the input-output linearization of a time-variant system with the parameter estimation is proposed. The parameter estimation method provides parameter estimates such that the estimated outputs asymptotically follow the measured outputs in a specified way. Since other unknown external disturbances or uncertainties can be lumped into existing parameters or considered as another separate parameters, the method is useful in practices exposed to diverse uncertainties and disturbances, and the designed controller becomes robust. And the design procedure and setting of tuning parameters are simple and clear due to the resulted linear design equations. The performances and the effectiveness of the proposed method are demonstrated via simulation studies.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.409-414
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• 2007

Wettability of solid surfaces with liquids is governed by the chemical properties and the microstructure of the surfaces. We report on the preparation of liquid-repellent surfaces using surface-attached monolayers of perfluorinated polymer molecules on porous silica substrates. A covalent attachment of the polymer molecules to the substrate is achieved by generation of the polymer chains through starting a surface-initiated radical-chain polymerization of a fluorinated monomer. To this, self-assembled monolayers of azo initiators are attached to silica substrates, which are used to kick off the polymerization reaction in situ. The growth of the fluorinated polymer films and the characterization of the obtained surfaces by surface plasmon spectroscopy, XPS, and contact angle measurements is described. It is shown that perfluorinated polymer films can be grown with controlled thicknesses on flat and even on porous silica surfaces, essentially without changing the surface roughness. The combination of the low surface energy coating and the surface porosity allows generation of materials which are both water and oil repellent.

• Elastomers and Composites
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• 제47권1호
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• pp.30-35
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• 2012

새로운 스타폴리머인 바이오폴리부타디엔은 리빙 음이온중합이라는 고분자의 정밀 합성법을 통하여 분자량, 분자량분포, 조성 및 세부구조를 제어하였다. 리빙 음이온중합에 의해 n-BuLi으로 개시된 polybutadienyllithium(PBDLi)의 연쇄말단이 ESO(Epoxidized Soybean Oil)의 기능성 그룹과 커플링 반응을 일으키며 스타폴리머를 합성한다. 분자량이 1,000/5,000/10,000(g/mol)인 PBDLi을 중합하여 THF존재하에서 반응 후 GPC에 의한 분자량 및 arms분석과 $^1H$-NMR, FT-IR에 의한 고분자 구조 분석을 통하여 바이오폴리부타디엔의 합성을 확인하였다.

• Korean Membrane Journal
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• 제8권1호
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• pp.67-73
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• 2006

Transparent materials are well known but preparation of transparent poly 2-hydroxyethyl methacrylate {poly (HEMA)} material by varying solvent is a new one and economically reliable. This material is prepared from hydroxyl based monomer HEMA by radical polymerization using benzoyl peroxide (BPO) as initiator and isobutanol, 2-butanol, 1-butanol, hexane and toluene as a solvent. The reaction temperature, time and stirring speed were set at $70^{\circ}C$, 4 hrs and 150 rpm, respectively. The polymer was characterized for functional group by IR spectroscopy. It was observed that the intensity of band at $1637 cm^{-1}$ a characteristic band of C=C stretching disappeared indicating that it was completely consumed after polymerization. It was observed that swelling percentage increases with increase as time passes but after a certain time a constant swelling percentage is achieved. SEM pictures reveals that poly (HEMA) prepared by different solvent shows pore with a distinguishable void up to several micrometers. The BET surface area, cumulative pore volume and average pore diameter is greater in poly (HEMA) prepared by hexane as a solvent compared to other solvents. Poly (HEMA) prepared by 1-butanol as a solvent shows higher glass transition temperature compared to other solvents. Poly (HEMA) prepared by different solvents shows $90{\sim}94%$ light transmission property from light transmission measurement and looks transparent.

• Macromolecular Research
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• 제15권7호
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• pp.633-639
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• 2007

A variety of NMR techniques were applied to the micro-chemical structural characterization of polyanilines prepared via an efficient synthetic method in a self-stabilized dispersion medium in which the polymerization was conducted in a heterogeneous organic/aqueous biphasic system without any stabilizers. Here, the monomer and growing polymer chain were shown to function simultaneously as a stabilizer, imparting compatibility for the dispersion of the organic phase, and as a form of flexible template in an aqueous reaction medium. Polymerizations predicated on this concept generated polyanilines with a low defect content: solution state $^{13}C-NMR$ and solid $^{13}CDD/CP/MAS$ spectroscopy indicated that the synthesized HCPANi and its soluble derivative, HCPANi-t-BOC, evidenced distinctly different NMR spectra with fewer side peaks, as compared to conventionally prepared PANis, and the complete structural assignments of the observed NMR peaks could be determined via the combination of both 1D and 2D techniques. Ortho-linked defects in HCPANi were estimated to be as low as 7%, as shown by a comparison of the integration of the carbonyl carbon resonance peaks.

• Macromolecular Research
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• 제9권3호
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• pp.150-156
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• 2001

Polystyrenes(PS) were grafted onto polypropylene(PP) in the PP solution by ultrasonic irradiation-initiated polymerization of styrene. The resulting products consisted of mixtures of homopolymers and PP-PS copolymer because of the homopolymerization of styrene itself and copolymerization with PP. The dependency of the designated polymerization on sonication times was investigated to monitor the evolution lion of the copolymerization. Formation of the PP-PS copolymer was confirmed by FTIR analysis of the reaction products after a proper separation procedure of free PS and PP-PS copolymer. It was found that the tendency for the formation of PP-PS copolymer was closely related with the phase behavior of the PP/styrene mixture which was also influenced by sonication time. In order to verify the effectiveness of the PP-PS copolymer as a compatibilizer for PP/PS blend, melt mixing of PP/PS/PP-PS was performed in a batch mixer. During the mixing, the average torque was higher for the blend containing PP-PS copolymer influencing compatibilization. In accordance with the results from FRIR analysis and torque measurement, the PS domain size remarkably decreased in the PP/PS/PP-PS blend.

• Macromolecular Research
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• 제15권2호
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• pp.173-177
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• 2007

Living anionic and cationic polymerizations have been combined to prepare various types of comb-like copolymers composed of polystyrene (PS) and polyisoprene (PI) blocks, with a precisely controlled architecture. According to the relative placement of these elementary building blocks, combs with randomly distributed PS and PI or with poly(styrene-b-isoprene) diblock branches (I & II, respectively) can be prepared. The reaction procedure initially includes the synthesis of a poly(chloroethylvinyl ether) using living cationic polymerization, which is used as the reactive backbone to successively graft $PS^-Li^+$ and $PI^-Li^+$ or $PI-b-PS^-Li^+$ to obtain structures (I) or (II). The synthesis of Janus-type PS-comb-b-PI-combs (III) initially involves the synthesis of a diblock backbone using living cationic polymerization, which bears two distinct reactive functions having either a protected or activated form. Living $PS^-Li^+$ and $PI^-Li^+$ are then grafted, in two separate steps, onto each of the reactive functions of the backbone, respectively.

• Macromolecular Research
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• 제14권3호
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• pp.373-382
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• 2006

A series of crosslinkable, waterborne polyurethanes (I-WBPUs) were prepared by in-situ polymerization using isophorone diisocyanate (IPDI)/poly(tetramethylene oxide) glycol (PTMG, $M_n$=2,000)/dimethylol propionic acid (DMPA)/ethylene diamine (EDA)/triethylamine (TEA)/aminoplast[hexakis(methoxymethyl)melamine (HMMM)] as a crosslinking agent. Typical crosslinkable, waterborne polyurethanes (B-WBPUs) blended from WBPU dispersion and aqueous HMMM solution was also prepared to compare with the I-WBPUs. The crosslinking reaction between WBPU and HMMM was verified using FTIR and XPS analysis. The effect of the HMMM contents on the dynamic mechanical thermal, thermal, mechanical, and adhesion properties of the I-WBPU and B-WBPU films were investigated. The storage modulus(E'), glass transition temperatures of the soft segment ($T_{gs}$) and the amorphous regions of higher order ($T_{gh}$), melting temperature ($T_m$), integral procedural decomposition temperature (IPDT), residual weight, $T_{10%}$ and $T_{50%}$ (the temperature where 10 and 50% weight loss occurred), tensile strength, initial modulus, hardness, and adhesive strength of both I-WBPU and B-WBPU systems increased with increasing HMMM content. However, these properties of the I-WBPU system were higher than those of the B-WBPU system at the same HMMM content. These results confirmed the in-situ polymerization used in this study to be a more effective method to improve the properties of the WBPU materials compared to the simple blending process.

• 한국안전학회지
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• 제19권1호
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• pp.81-87
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• 2004

Composite particles using inorganic and organic chemicals were synthesized and the results of those reaction were compared to variation of temperature and agitation speed in presence of $CaCO_3$ which was adsorbed SDBS. Also the synthesises were optimized according to conversion rate of composite particles. In inorganic/organic core-shell composite particle polymerization, $CaCO_3$ adsorbed by 0.5wt% surfactant SDBS was prepared initially and then core $CaCO_3$ was encapsulated by sequential emulsion polymerization using MMA at the addition of APS 3.16${\times}$$10^{-3}$mol/L to minimize the coagulated PMMA particle itself during MMA shell polymerization. Encapsulated PMMA on $CaCO_3$ as inorganic/organic core-shell particles was verified by FT-IR and DSC analysis. It was found that the $CaCO_3$ was very well encapsulated by PMMA as shell. The surfaces were distinctly found as spindle shape and broad particle distribution after capsulation.