• Elastomers and Composites
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• v.55 no.2
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• pp.95-102
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• 2020

Currently, peroxide cure is a widely used cure system for rubber materials. To improve its effectivity, co-agents are used to enhance the peroxide efficiency and mechanical properties of rubber materials. Co-agents are multifunctional organic compounds that are highly reactive towards free radicals. These co-agents provide higher cross-link densities for a given peroxide concentration and improve the mechanical properties of peroxide-cured rubber composites. In this study, trimethylolpropane trimethacrylate (TMPTMA) and high vinyl 1,2-polybutadiene (HVPBD) were used as co-agents. In order to obtain a concentration that achieves a favorable balance between mechanical properties and co-agent concentration, this research investigated the effects of co-agent content on the curing characteristics, chemical structures, and mechanical properties of HNBR composites. Additionally, the heat aging properties and compression sets of HNBR composites were investigated. Based on the results, we found that the HNBR composites with TMPTMA co-agents exhibited higher Shore A hardness and 10% modulus and better heat aging resistance and compression set than that of the HVPBD co-agent. The heat aging resistance and compression set deteriorated with increasing HVPBD content.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.1967-1971
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• 2013

Aim of our study is finding adsorbents suitable for pre-concentration of chemical warfare agents (CWAs). We considered Tenax, bare silica and polydimethylsiloxane (PDMS)-coated silica as adsorbents for dimethyl methylphosphonate (DMMP) and dipropylene glycol methyl ether (DPGME). Tenax showed lower thermal stability, and therefore, desorption of CWA simulants and decomposition of Tenax took place simultaneously. Silica-based adsorbents showed higher thermal stabilities than Tenax. A drawback of silica was that adsorption of CWA simulant (DMMP) was significantly reduced by pre-treatment of the adsorbents with humid air. In the case of PDMS-coated silica, influence of humidity for CWA simulant adsorption was less pronounced due to the hydrophobic nature of PDMS-coating. We propose that PDMS-coated silica can be of potential importance as adsorbent of CWAs for their pre-concentration, which can facilitate detection of these CWAs.

• Bulletin of the Korean Chemical Society
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• v.27 no.3
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• pp.395-398
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• 2006

Nerve agents (sarin, tabun, soman and VX) are class of military important substances able to cause many severe intoxications during few minutes. Currently, the threat of misuse of these agents is daily discussed. Unfortunately, there is no single antidote able to treat intoxication caused by all of these agents. Owing to this fact, new generation of antidotes, especially acetylcholinesterase (AChE; EC 3.1.1.7) reactivators, is still developed. In this study, we have tested four newly developed AChE reactivators: 1-(4-hydroxyiminomethylpyridinium)- 5-(4-carbamoylpyridinium)-3-oxa-pentane dibromide (1), 1-(3-hydroxyiminomethylpyridinium)-5-(4-carbamoylpyridinium)-3-oxa-pentane dibromide (2), 1,5-bis(2-hydroxyiminomethylpyridinium)-3-oxa-pentane dichloride (3) and 1,5-bis(4-hydroxyiminomethylpyridinium)-3-oxa-pentane dibromide (4) for their potency to reactivate in vitro tabun and cyclosarin-inhibited AChE. Their reactivation efficacy was compared with currently the most promising oxime HI-6 (1-(2-hydroxyiminomethylpyridinium)-3-(4-carbamoylpyridinium)-2-oxa-propane dichloride). According to obtained results, two AChE reactivators 1 and 4 were able to reactivate tabun-inhibited AChE. On the contrary, there was no better AChE reactivator than HI-6 able to reactivate cyclosarin-inhibited AChE.

• Journal of the Korean Applied Science and Technology
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• v.20 no.2
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• pp.81-86
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• 2003

To prepare alkaline degreasing agents(SADAs), tetrasodium pyrophosphate(TSPP), $Na_2CO_3$, Tetronix T-701 (T-701), Na-dioctyl sulfosuccinate(303C), Demol C, and MJU-100A were blended. The prepared degreasing agents were tested with steel specimens and the results were as follows. The degreasing powers of SADA-6($Na_2CO_3$ 50g/TSPP 25g/T-701 10g/303C 15g/Demol C 12g/MJU-100A 8g/water 130g mixture) for press-rust preventing oil were 98% and 99% degreasing at 4wt%, 70 $^{\circ}C$ and 90 $^{\circ}C$, respectively; for quenching oil, the degreasing power of SADA-6 was 92% degreasing at 4wt% and 70 $^{\circ}C$. From these results, it was proved that the SADA-6 exhibits a good degreasing power. Foam heights measured immediately after foaming by Ross & Miles method and Ross & Clark method at 6wt% and 60 $^{\circ}C$ were 16mm and 40mm, respectively. SADA-6 was proved a good low foaming degreasing agent.

• Journal of radiological science and technology
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• v.43 no.4
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• pp.273-280
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• 2020

In this study, the P contrast agent of Iopamidol, which is a nonionic iodide contrast agent most commonly used as a vascular contrast agent in medical institutions, and the O contrast agent of Ioversol, were studied. The physicochemical changes according to the temperature change were compared and analyzed using the Bruker Avance 500MHz Nuclear Magnetic Resonance Spectrometer owned by the Korea Basic Science Institute (KBSI). There was no physical or chemical change in the O contrast medium of Ioversol formulation in temperature change. However, in the P contrast agent of Iopamidol, a doublet peak began to appear in the 1.1 ppm region of the sample at 60℃, and the doublet peak was clearly observed in the sample at 80℃. As a result of this study, 1H-NMR analysis revealed that the P contrast agent of the Iopamidol formulation was dissociated from chemical bonds as it rose to a high temperature of 60℃ or higher, resulting in the formation of foreign substances. It was evaluated that the O contrast agent of Ioversol formulation had physico-chemical stability than the P contrast agent of Iopamidol formulation. As shown in this study, it is necessary to analyze the physical and chemical changes of contrast agents according to various environmental factors.

• Clean Technology
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• v.16 no.2
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• pp.103-116
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• 2010

It has been reported that the LCD panel market in the FPD industry is become growing and its panel size and production capacity are increasing, and its manufacturing technique is improved every year. FPD manufacturing process requires high cleanliness in its overall process. Especially, FPD cleaning process which accounts for 30~40% of total manufacturing process is very important in its technological and productivity aspects. It is difficult to remove residual liquid-crystal in the fine gap after liquid-crystal injection process in the cell. In this study, aqueous cleaning agents with excellent cleaning, rinsing, and penetrating abilities, but minimum ion content for LCD panel were formulated through mixing glycol ether-type and glycol dimethyl ether-type solvents and nonionic surfactants which are widely used as raw materials for alternative cleaning agents because of environmental regulation at home and abroad. And the formulated cleaning agents were applied to clean FPD liquid crystal after its injection in the cell. Physical properties, cleaning efficiencies, and rinsabilities of the formulated cleaning agents with different combination ratios of solvents, surfactants and additives were measured. As experimental results, the formulated cleaning agents showed higher wetting indices and cloud point than the traditional commercial cleaning agent. And it was found that cleaning efficiencies of the formulated cleaning agents were influenced by the structure of main solvents in them and the types of liquid crystal as soil for cleaning. The best cleaning agents among the formulated cleaning agents showed similar cleaning efficiencies and better rinsabilities compared to the conventional cleaning agent.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1439-1444
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• 2002

6-Nitroquipazine has higher binding affinity for SERT than other selective serotonin reuptake inhibitors. We have prepared 6-nitroquipazine based rhenium complexes which would lead to the development of potential SPECT imaging agents with $^{99m}Tc$ for 5-HT transporter.

• Bulletin of the Korean Chemical Society
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• v.26 no.7
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• pp.1135-1137
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• 2005

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1147-1151
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• 2009

The synthetic route of novel 3′-C-methyl carbodine analogue is described. The construction of tertiary alcohol at 3′- position of carbodine analogues was successfully made via sequential [3,3]-sigmatropic rearrangement, ring-closing metathesis (RCM) and stereoselective dihydroxylation reactions starting from ethyl glycolate.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.684-689
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• 2010

We synthesized a variety of SAPO catalysts with various structure directing agents by the hydrothermal method and applied them to the D-xylose dehydration. Single or mixtures of organic amines, viz. tetraethylammonium hydroxide(TEAOH), dipropylamine(DPA), diethylamine(DEA), morpholine and diethanolamine(DEtA) were used as structure directing agents. The $N_2$-isotherm, $NH_3$-temperature programmed desorption(TPD) and temperature programmed oxidation(TPO) were conducted to characterize SAPO catalysts. Among tested SAPO catalysts, the SAPO-34 synthesized with morpholine showed the highest furfural yield. The external surface area as well as the surface concentration of acid sites appeared to affect the catalytic activity for the dehydration of xylose into furfural.