• Analytical Science and Technology
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• v.18 no.2
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• pp.97-103
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• 2005

The various size and morphology microcapsules were prepared to produce smell sweet by heating condensation reaction of melamine and formaldehyde using 5-types of surfactants such as the laurylbenzenesulfonic acid sodium salt (SDS), polyvinylpyrrolidon (PVP), polyvinyl alcohol (PVA), Span-80 and 2-acrylamido-2-methyl-1-1 propanesulfonic acid (AMP). As result it was found that the size and morphology of microcapsule is intimately associated with a kind of surfactants. In order to prepare microcapsule with antibacterial, the silver nanoparticle was prepared by gamma-irradiation. microcapsule with silver nanoparticle was prepared.

• Journal of the Korean Chemical Society
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• v.17 no.1
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• pp.60-66
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• 1973

When m-phenylenediamine (MPD) or m-aminophenol (MAP) was treated with formaldehyde(F), under $N_2$ stream, at the temperature $-5\sim0^{\circ}C$, addition condensation occurred and insoluble resins formed immediately. Under the same reaction conditions m-phenylenediamine, m-aminophenol and formaldehyde also easily copolycondensed and insoluble MPD-MAP-F type copolymer formed. MPD-MAP-F type copolycondensed resin was superior in both heat-resistant property and adsorptivity of Bromophenol Blue or Methylene Blue than the MPD-F and MAP-F type resins. From the result of TGA, under $N_2$stream, MPD-MAP-F resin showed about $40\%$ weight loss at $800^{\circ}C$, and this type of resin 1g adsorbed 308mg of Bromophenol Blue.

• Toxicological Research
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• v.13 no.1_2
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• pp.39-48
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• 1997

Cyclophosphamide(25, 50 or 100 mg/kg), orally administered to male Sprague-Dawley rats, caused a time- and dose-dependent thymic atrophy. In the light microscopic examination of the atrophic thymus, thymocytes with condensed or fragmented nucleus were multifocally observed in the cortical region, started to increase 8 hr after CPA treatment and reached to the maximal level at 16 hr, although such cells were not seen after 48 hr when the severe depletion of thymocytes were marked. In agarose gel electrophoresis to analyze the DNA changes, DNA extracted from atrophic thymus showed a oligonucleosomal laddering at the corresponding time to morphological changes. In an additional supportive experiment, thymocytes showing morphological changes, nuclear condensation or apoptotic body, exhibited a positive reaction to immunoperoxidase staining using in situ apoptosis detection kit. Separately, agarose gel electrophoresis of DNA from bone .marrow cells was performed to investigate the involvement of bone marrow cells in the process of thymocyte apoptosis. Although DNA laddering was slightly increased 2 and 4 hr after treatment, no clear correlation was inferred. Taken togather, it is concluded that thymocytes showing morphological changes in thymic atrophy induced by cyclophosphamide administration represent an apoptosis having biochemical nature of programmed cell death.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1627-1637
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• 2012

The coupling reaction between 5-bromo-3-phenylbenzo[c]isoxazole and diphenylamine followed by further condensation with a mono-, di- or ter-acetyl aromatic compound in the presence of diphenyl phosphate at $145^{\circ}C$ gave a novel asymmetric diarylquinolines, oligoquinolines with diphenylamine endgroups, and a first generation quinoline dendrimer in 41-82% isolated yield. The electrochemical and photophysical properties of the oligoquinolines were characterized by cyclic voltammograms (CVs) and spectroscopy. All the quinolines emit bright sky blue light due to charge transfer from quinoline group to diphenly amine with very high quantum efficiency (> 90%). Organic light-emitting diodes (OLEDs) were fabricated using these quinolines as emitting materials. Among different device architectures explored, OLEDs with a structure of ITO/PEDOT (40 nm)/TAPC (15 nm)/D-A quinoline (40 nm)/TPBI (30 nm)/LiF (1 nm)/Al using TAPC as an electron blocking layer and TPBI as a hole blocking layer gave the best performance. A high external quantum efficiency in the range of 1.2-2.3% were achieved in all the quinolines with the best performance in BBQA(5). Our results indicate diarylamino-substituted oligoquinoline and dendrimer are promising materials for OLEDs applications.

• Korean Journal of Materials Research
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• v.22 no.12
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• pp.696-700
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• 2012

(Na, K) $NbO_3$ thick film was successfully achieved using a sol-gel coating process with the addition of polyvinylpyrrolidone (PVP) to a metal alkoxide solution. The transparent coating solution, mixed with Nb:PVP = 1:1 in a molar ration, was synthesized by evaporating the solvent to over 62.5 wt%. Additive PVP increased the viscosity of the solution so that the coating thickness could be enhanced. The thickness of the (Na, K) $NbO_3$ film assisted by PVP was ca. 320 nm at the time of deposition; this value is four times thicker than that of the sample fabricated without PVP. Also, due to PVP binding with the OH groups of the metal alkoxide, the condensation reaction in the film was suppressed. The crystalline size of the (Na, K) $NbO_3$ films assisted by PVP was ca. 15 nm smaller than that of the film fabricated without PVP. After the sintering process at $700^{\circ}C$, the (Na, K) $NbO_3$ films were mainly composed of randomly oriented (Na, K) $NbO_3$ phase of perovskite crystal structure, including a somewhat secondary phase of $K_2Nb_4O_{11}$. However, by adding PVP, the content of the secondary phase became quite smaller than that of the sample without PVP. It was thought that the addition of PVP might have the effect of restraining the loss of potassium and that PVP could hold metalloxane by strong hydrogen bonding before complete decomposition. Therefore, the film thickness of the (Na, K) $NbO_3$ films could be considerably advanced and made more crack-free by the addition of PVP.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.203-209
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• 2017

The propenyl ether-type monomers which are applicable for cationic photo-polymerization were synthesized by the condensation reaction of mono and di-functional alcohol with allyl bromide. To examine photo-curable reactivity, these monomers were combined with cationic photoinitiator to prepare coating composition. As a result, the initial rate of polymerization of POMB in mono propenyl ether type was 10.2, which was relatively lower than BPOB in di-propenyl ethers type. However, POMB containing 1.5mol% photoinitiator almost quantitatively reacted within 90 seconds. In addition, Sulfonium salt type photo-initiators containing long-alkyl group showed good solubility with monomers and apperaed to have comparatively higher rate of polymerization and conversion ratio when applying DPSA and DPST which have high acidity on all monomers.

• Journal of the Korean institute of surface engineering
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• v.33 no.2
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• pp.77-86
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• 2000

In this study effects of La starting compounds and substrates on the densification of (P $b_{0.92}$L $a_{0.05}$)Ti $O_3$ thin films were investigated. After the heat treatment on platinized silicon at $650^{\circ}C$ for 30min thickness of PLT(i) thin films (from La-isopropoxide) shrank by 27%, while 33% reduction occurred for PLT (a) thin films (from La-acetate). These PLT(i) films showed less densified surface microstructure compared to the PLT (a) . Lower shrinkage of the films on platinized silicon than on bare silicon (41% and 40% for PLT (i) and PLT (a) respectively) is attributed to the earlier development of crystallinity in the film, which arrests film densification. In order to maximize sintering before crystallization, heat treatment at $400^{\circ}C$ for 3 hours followed by $650^{\circ}C$ for 30 min was attempted. This method increased the shrinkage of the PLT (i) and PLT (a) films two times and 1.5 times as much as that observed for the films heat treated at $650^{\circ}C$ for 30min, respectively. FTIR results indicated that first pyrolysis in the film is associated with the burning of acetate ligands. Condensation reaction between OHs was found to occur preferentially between $350^{\circ}C$ and $450^{\circ}C$, whereas majority of polycondensation between ROH-OH appears to occur until $300^{\circ}C$ and be completed below $450^{\circ}C$.EX>.

• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1218-1242
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• 2002

Photochemical reactions of aromatic carbonyl compounds with silyl ketene acetals have been explored. Irradiation of acetonitrile or benzene solutions containing aryl aldehydes or ketones in the presence of silyl ketene acetals is observed to promo te formation of ${\beta}-hydroxyester$, 2,2-dioxyoxetane and 3,3-dioxyoxetane products. The ratios of these photoproducts, which arise by competitive single electron transfer (SET) and classical Paterno-Buchi mechanistic pathways, is found to be dependent on the degree of methyl-substitution on the vinyl moieties of the ketene acetals in a manner which reflects expected alkyl substituent effects on the oxidation potentials of these electron rich donors. An analysis of the product distribution arising by irradiation of a solution containing butyrophenone (6) and the silyl ketene acetal 9, derived from methyl isobutyrate, provides an estimate of the rate constants for the competitive Norrish type Ⅱ, SET and Paterno-Buchi processes occuring. Finally, sequences involving silyl ketene acetal-aryl aldehyde or ketone photoaddition followed by 2,2-dioxyoxetane hydrolysis represent useful procedures for Claisen-condensation type, ${\beta}-hydroxyester$ synthesis.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.138-142
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• 1999

Imide-containing diamine and dicarboxylic acid monomers, N-(4-aminophenyl)-4-aminophthalimide(APAP), N-(4-carboxyphenyl)-4-carboxyphthalimide(CPCP), N,N'-oxydiphenylenebis(4-aminophthalimide)(ODPAP) and N,N'-oxydiphenylenebis(4-carboxyphthalimide)(ODPCP) were prepared. Poly(amide-imide)s were prepared by condensation reaction of the diamine and the dicarboxylic acid monomers. Poly(amide-imide)s were also prepared from the diamine monomers and aromatic acid chlorodes such as terephthaloyl chloride and isophthaloyl chloride. The polymers possess inherent viscosity of 0.18~0.67 dL/g and brittle films were cast from NMP/LiCl solution. The poly(amide-imide)s are easily soluble in NMP/LiCl and also partially soluble in polar aprotic solvents such as DMF, DMSO, NMP and DMAc even at $80^{\circ}C$. DSC traces of polymers showed no glass transition temperature and melting temperature, and TGA traces showed a 10% weight loss at $500^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.42 no.1
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• pp.50-55
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• 2005

New fast proton-conducting organic-inorganic nanocomposite membranes were successfully fabricated using polymer matrix obtained through proper oxidation of thiol ligands in (3-Mercaptopropyl) trimethoxysilane (MPTS) and hydrolysis/condensation reaction of (3-glycidoxypropyl) trimethoxysilane (GPTS). The obtained nanocomposite membranes showed relatively hirh proton-conductivity over $10^{-2}S/cm$ at $ 25^{circ}C$. The proton conductivities of the fabricated composite membranes increased up to $3.6{\times}10^{-1}$ S/cm cm by increasing temperature and relative humidity to $70^{circ}C$ and 100 $100RH\%$. The high proton conductivity of the composites Is due to the proton conducting path through the GPTS-derived 'pseudo-polyethylene oxide 'network in which sulfonic acid ligands work as a proton donor.