• KSBB Journal
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• 제21권5호
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• pp.401-404
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• 2006

MAA와 EGDMA를 단량체 및 가교제로 한 일체형 컬럼은 친수성의 구조표면을 하고 있어 쉽게 시료와 수소결합 등 강한 상호작용을 할 수 있다. 본 실험에서는 카페인과 트립토판을 분리물질로 선택하였으나 완전한 분리도를 얻을 수가 없었다. 이는 일체형 컬럼의 제조 시 여러 요인에 기인하다. 중합혼합반응물질의 양의 조성과 반응조건이 적절하지 못하는 등 원인으로 생각된다. 따라서 일체형 컬럼의 분리도를 향상시키기 위한 많은 실험이 요구된다.

• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.296-300
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• 1997

Glucose syrup and lactose, mixed with citric acid as a polymerizing catalyst, was processed using twin screw extruder, in which 40 of L/D(length/diameter) ratio was designed to provide sufficient retention in extruder for polymerization of sugars. The polymerization yields of glucose syrup were 36.90%, 55.44% and 77.10% at 160, 180 and 20$0^{\circ}C$, respectively, while those of lactose were 26.45%, 38.16% and 45.86% at the same temperatures. Gel permeation chromatography exhibited that the higher molecular weight fractions were increased with extrusion temperature, which also led to increasing hydrodynamic intrinsic viscosity. Both uco-oligosaccharides and lacto-oligosaccharides produced by extrusion of glucose syrup and lactose were stable for thermal treatments over a wide range of pH3.0~11.0. In addition, $\alpha$-amylase and amyloglucosidase treatment of gluco-oligosaccharides did not affect the solution viscosity, indicating the random linkage rather than $\alpha$-1, 4 linkages of glucose and thus the potential applications as a dietary fiber. In this research it was clearly observed that twin screw extrusion can be successfully utilized to produce gluco-oligosaccharides and lacto-oligosaccharides rapidly and continuously in conjunction with selective control of polymerized composition.

• 한국응용과학기술학회지
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• 제19권4호
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• pp.265-272
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• 2002

$CaCO_{3}$ absorbed sodium lauryl sulfate (SLS) surfactant was prepared, Core-shell polymers of inorganic/organic pair, which have both core and shell component, were synthesized by sequential emulsion polymerization using styrene(St) as a shell monomer and potasium persulfate (KPS) as an initiator, We found that when $CaCO_{3}$; core prepared by adding 2,0 wt% SLS, $CaCO_{3}$ core/PSt shell polymerization was carried out on the surface of $CaCO_{3}$ particle without forming the new PSt particle during St shell polymerization in the inorganic/organic core-shell polymer preparation, The structure of core-shell polymer were investigated by measuring the degree of decomposition of $CaCO_{3}$ using HCl solution, thermal decomposition of polymer composite using thermogravimetric analyzer and morphology by scanning electron microscope.

• Macromolecular Research
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• 제12권5호
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• pp.512-518
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• 2004

We have synthesized a novel macromonomer of vinyl-terminated bifunctional polyurethane having a molecular weight of 37,000 g/mol and successfully applied it to the dispersion polymerization of methylmethacrylate(MMA). We verified the presence of the vinyl terminal group and the macromonomer grafted onto the poly(ethylene glycol)(PEG) block in the PMMA particles by using $^1$H and $\^$13/C NMR spectroscopies. Monodisperse PMMA microspheres that have good uniformity of 1.01 were prepared at 20 wt% macromonomer content; we investigated the characteristics of the PMMA particles in terms of their molecular weight, molecular weight distribution, size of the particles, thermal properties, and glass transition temperature. We have found that the synthesized polyurethane macromonomer is an effective stabilizer.

• 한국응용과학기술학회지
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• 제18권4호
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• pp.273-284
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• 2001

A series of microcapsule were synthesized by using several PCM(Phase Change Material) as a core material and gelatin/arabic gum, melamine/formaldehyde as a shell material. Coacervation technique and in situ polymerization were adopted in synthesizing microcapsules. In the microencapsulation by coacervation, tetradecane and octadecane were used as core materials. In the microencapsulation by situ polymerization tetradecane, pentadecane, hexadecane, heptadecane, octadecane, and nonadecane were used as core material. The synthesized microcapsule was examined to observe the shape of the microcapsule. The particle size analysis was performed by particle size analyzer. The thermal properties(e.g. melting point, heat of melting, crystallization temperature, heat of crystallization, differences between melting point and crystallization temperature) were obtained by DSC(Differential Scanning Calorimeter). The stirring rate effect was investigated during the microencapsulation. It was found that with increasing the stirring rate much smaller microcapule was produced. However, this did not necessarily lead to formation of spherical microcapsule.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.30-33
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• 2006

Transparent indium tin oxide (ITO) anode surface was modified using $O_3$ Plasma and organic ultrathin buffer layers were deposited on the ITO surface using 13.56 MHz RF plasma polymerization technique. The EL efficiency, operating voltage and lifetime of the organic light-emitting device (OLED) were investigated in order to study the effect of the plasma surface treatment and role of plasma polymerized organic ultrathin buffer layer. Poly methylmethacrylate (PMMA) layers were plasma polymerized on the ITO anode as buffer layer between anode and hole transport layer (HTL). The plasma polymerization of the organic ultrathin layer were carried out at a homemade capacitive-coupled RF plasma equipment. N,N'-diphenyl-N,N'(3- methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) as HTL, Tris(8-hydroxyquinolinato) Aluminum $(Alq_3)$ as both emitting layer (EML)/electron transport layer (ETL), and aluminum layer as cathode were deposited using thermal evaporation technique. Effects of the plasma surface treatment of ITO and plasma polymerized buffer layers on the OLED performance were discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.114-115
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• 2007

In this paper, it was demonstrated that organic thin-film transistors (OTFTs) were fabricated with the organic passivation layer by vapor deposition polymerization (VDP) processing, In order to form polymeric film as an passivation layer, VDP process was also introduced instead of spin-coating process, where polymeric film was co-deposited by high-vacuum thermal evaporation from 6FDA and ODA followed by curing, Field effect mobility, threshold voltage, and on-off current ratio with 450-nm-thick organic passivation layer were about $0.21\;cm^2/Vs$, IV, and $1\;{\times}\;10^5$, respectively.

• 한국염색가공학회지
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• 제33권3호
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• pp.147-152
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• 2021

Bulk polymerization was used to produce poly(vinyl acetate) with different molecular weights, which were then saponified to prepare poly(vinyl alcohol) (PVA) with different molecular weights. With P_n of 2,060 and 3,240, the optimum film formation concentrations of PVA were found 7.5wt.% and 6.5wt.%, respectively. The drawing characteristics of the PVA film prepared at the optimum film formation concentrations were experimented, as well as the thermal characteristics of the PVA film based on the drawing ratio were observed. When the drawing velocity was fixed, it was found that the drawing ratios of all samples decreased as the heat band gap increased, and the melting temperature of the PVA film slightly increased as the drawing ratio increased regardless of the P_n of PVA.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.34-37
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• 2000

The effect of novel N-crotyl-N,N-dimethyl-4-methylanilinium hexafluroantimonate (CMH) curing agent on cure behavior and thermal properties of DGEBA epoxy cationic system was investigated. From DSC measurements of DGEBA/CMH system, it was shown that this system exhibits an excellent thermal latent characteristic in a given temperature and reveals complex cure behavior as indicated by multiple exotherms. The conversion and conversion rate of DGEBA/CMH system increased with increasing the concentration of initiator due to high activity of CMH. Viscoelastic properties during gel formation of DGEBA with CMH were investigated by rheological techniques under isothermal condition. The gel time obtained from the modulus crossover. point t(G')=G", was affected by high curing temperature and concentration of CMH, resulting in high degree of network formation in cationic polymerization. The thermal stabilities were discussed in terms of the activation energy for decomposition and thermal factors determined from TGA measurements.ents.

• ETRI Journal
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• 제24권6호
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• pp.409-414
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• 2002

This paper investigates the absorption and emission changes in poly(di-n-hexylfluorene)s. We prepared the poly(di-n-hexylfluorene)s end capped with 2-bromofluorene, 2-bromo-9,9-di-n-hexylfluorene, and 9-bromoanthracene through Ni (0) mediated polymerization. In addition, we also synthesized a structurally distorted copolymer of 2,7-dibromo- 9,9-di-n-hexylfluorene and 9,9-bis(4-bromophenyl) fluorene end capped with 2-bromofluorene through the same polymerization method. The absorption and emission changes of these polymers between before and after thermal annealing in a nitrogen atmosphere clarify the role of aggregate/excimer formation in poly(fluorene)s. The large absorption changes must be attributed to aggregate formation (ground state interaction), which causes only a slight red shift of the vibronically structured emission bands. We assign the additional long wavelength emission as an excimer band (excited state interaction), which is preferably formed at chain ends.