• Polymer(Korea)
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• v.34 no.2
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• pp.108-115
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• 2010

The effects of acid-treated MWCNT and coupling agent on properties of MWCNT/SBR are investigated in this work. The MWCNTs oxidized using sulfuric and nitric acids were analyzed by the Raman scattering and Fourier transformed infrared spectroscopy(FT-IR). The FT-IR results indicate the presence of -COOH groups in the treated samples, and Raman spectroscopy of the acidtreated MWCNTs further corroborates the formation of surface defect due to the introduction of carboxyl groups. And the nanocomposites reinforced with MWCNTs were characterized extensively using the scanning electron microscopy(SEM), electrical conductivity, thermal conductivity, and tensile properties measurements. The results showed that nanocomposites onto acid-treated MWCNTs enhanced mechanical properties compared to those containing MWCNTs without acid treatment. These findings confirmed the improved interfacial interactions between MWCNTs and SBR arising from the coupling agents. But the electrical and thermal conductivity of nanocomposites decreased due to the chopping and formation of surface defects of MWCNTs.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.673-679
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• 1991

The electrochemical reduction of N-tert-butylbenzothiazole-2-sulfenamide (TBBS; vulcanization accelerator) was investigated by direct current, differential pulse polarography, cyclic voltammetry and controlled potential coulometry. The electrode reduction of TBBS proceeded E-C-E-C reaction mechanism by four electrons transfer at irreversible one wave (-2.31 volts vs. Ag/0.1M AgN$O_3$ in AN). As the results of controlled potential electrolysis, mercaptobenzothiazole (MBT), benzothiazole disulfide (MBT dimer) and extricated sulfur were products which followed by cleavage of the sulfenamide (-S-N=) bond. Upon the basis of products analysis and polarogram interpretation with pH variable, electrochemical reaction mechanism was suggested.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.680-688
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• 1991

The electrochemical reduction of N-oxyldiethylenebenzothiazole-2-sulfenamide (ODBS; vulcanization accelerator) was investigated by direct current polarography, differential pulse polarography, cyclic voltammetry and controlled potential coulometry. The irreversible electrode reduction of ODBS proceeded E-C-E-C reaction mechanism by three electrons transfer with irreversible one wave (-1.86 volts vs. Ag/0.1 M AgN$O_3$ in AN). As the results of controlled potential electrolysis, mercaptobenzothiazole (MBT), benzothiazole disulfide (MBT dimer) and extricated sulfur were products which followed by cleavage of the sulfenamide (-S-N=) bond. Upo the basis of products analysis and polarogram interpretation witli pH variable, electrochemical reaction mechanism was suggested.

• Polymer(Korea)
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• v.27 no.5
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• pp.436-442
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• 2003

Thermosetting elastomer such as EPDM (Ethylene Propylene Dien Rubber) has been applied to the sponge weatherstrip of a vehicle as a main material. However, the thermosetting elastomers have limited recycling and have brought about the environmental problems. Furthermore, many steps of the manufacturing process such as formulation, mastication and vulcanization make difficult to control uniformity of the endproducts. These problems of current EPDM weatherstrip necessitated development of a new recyclable material, Thermoplastic Vulcanizates (TPV). In this study the influence of the water contents, and the processing conditions. On the foam density and structure in water blowing process was carried out. We found that TPV also can be foamed with water, maintaining the uniformity form this study. Therefore, many inevitable problems of EPDM weatherstrip can be solved, and this new technique is expected to take a roll of making a breakthrough in the rubber industry.

• Polymer(Korea)
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• v.25 no.1
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• pp.63-70
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• 2001

The objective of this study was to investigate the effect of cure type on the processing and physical properties under conditions of similar stress-strain properties. On the carbon black filled natural rubber(NR) based compound, the induction time decreased, but the cure rate became fast with increasing loading of sulfur donor agent. Tensile strength was little affected on the curing type. However, elongation generally decreased with increasing accelerator. Effect of cure type on the blow-out properties was followings: CV

• THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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• v.1 no.1
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• pp.191-211
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• 1995

This experiment was designed to study the change of cytotoxic and antitumor effects according to the prebrewed method of Semen Tiglii and Rhizoma Coptidis. The cytotoxic and antitumor effects were evaluated on human cell lines(A 549, Caki-1, LL2, Sarcoma 180, NIH/3T3) after exposure to prebrewed Semen Tiglii and Rhizoma Coptidis water extract 0.1, 0.2, 0.4, 0.8, 1.6 mg/ml using in MTT assay, LDH, colony forming efficency and SRB assay which were regarded as a valuable method for cytotoxic and antitumor effects of unknown compound on tumor cell lines. The results obtained in this studies were as follows. 1. The cytotoxicity from the result of MTT assay was low slightly in the ST II(炒巴豆霜), high in the ST III(醋炒巴豆). The cytotoxicity of ST I + RC(生巴豆霜加黃連) was similar to that of STI(生巴豆霜). 2. The cytotoxicity from the result of LDH was low slightly in the ST Ⅱ (炒巴豆霜), high in the ST III(醋炒巴豆). The cytotoxicity of ST I + RC(生巴豆霜加黃連) was similar to that of ST I(生巴豆霜). 3. The antitumor affect on A 549 tumor cell from the result of colony forming efficiency was low slightly in the ST II (炒巴豆霜) and ST I + RC(生巴豆霜加黃連). 4. The antitumor effect on Caki-1 tumor cell from the result of SRB assay was low slightly in the ST II (炒巴豆霜). 5. Median survival time and Increased life span increased slightly in the ST I RC(生巴豆霜加黃連) and ST II (炒巴豆霜). 6. The inhibitory effect on the growth of Sarcoma 180 and Lewis lung carcinoma tumor cell increased slightly in the ST I + RC(生巴豆霜加黃連) and ST II (炒巴豆霜).

• Journal of Energy Engineering
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• v.28 no.4
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• pp.42-47
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• 2019

In this study, combustion characteristics were measured by selecting di-n-buthylamine, which is widely used as an emulsifier, insecticide, additive, rubber vulcanization accelerator, corrosion inhibitor, and raw material for dye production. The flash point of the di-n-buthylamine was measured by Setaflash, Pensky-Martens, Tag, and Cleveland testers. And the AIT of the di-n-buthylamine was measured by ASTM 659E. The explosion limits of the di-n-buthylamine was calculated using the measured flash points by Setaflash tester. The flash point of the di-n-buthylamine by using Setaflash and Pensky-Martens closed-cup testers were experimented at 38 ℃ and 43 ℃, respectively. The flash points of the di-n-buthylamine by Tag and Cleveland open cup testers were experimented at 48 ℃. The AIT of the di-n-buthylamine was experimented at 247 ℃. The LEL and UEL calculated by using lower and upper flash points of Setaflash tester were calculated at 0.69 vol% and 7.7 vol%, respectively. The measurement of the flash point measurement and the calculation method of the explosion limit prediction presented in this study can be used to study the fire and explosion characteristics of the other combustible liquids.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.608-613
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• 1998

The purpose of this experiment was the physical properties of rubber compounds with DPCB and pure carbon black. Si-O peak in the silcia surface was observed at the range of wavenumber from 1,100 to 1,200 in the DPCB by FT-IR analysis. Cure rate of rubber compounds containing DPCB and organic silane coupling agent were (Si69) delayed compared with those containing pure carbon black. 300% modulus and interaction coefficient of DPCB with silane coupling agent were higher than those of pure carbon black and PICO weight loss amount showed constant value. It was found that $0^{\circ}C$ tan$\delta$ of rubber compounds with DPCB was larger than those of pure carbon black at 2.0% silane coupling agent based on 50 phr DPCB and $60^{\circ}C$ tan$\delta$ of rubber compounds with DPCB decreased as increasing the usage coupling agent. Consequently, it is postulated that DPCB is strong candidate material for lowering rolling resistance under constant abrasion resistance.

• Elastomers and Composites
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• v.48 no.2
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• pp.114-124
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• 2013

To study the effects of structural difference and fatty acid chain length of glyceride, new dispersion agents having various glyceride structures such as mono-, di-, and tri-, were prepared using glycerol extracted from palm oil and fatty acid having various chain length ranges from 12 to 18. These dispersion agents were mixed with the rubber compounds and compared with conventional metal salt dispersion agents. Glyceride dispersion agent provided remarkable improvement in silica dispersion, compared to metal salt fatty acidic one, even though the viscosity of mixtures was relatively high due to low lubricating effect, and this was approved by mechanical properties, wear properties, and Payne effect. Also, the longer in chain length of fatty acid and the smaller in numbers of fatty acid, the dispersity of silica was improved.

• Elastomers and Composites
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• v.36 no.3
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• pp.188-194
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• 2001

Thermoplastic elastomers based on dynamically vulcanized NR/TOR/PP (rubber/PP=70/30) blends were prepared in a Haake banbury mixer. Effect of TOR content on the mechanical, dynamic mechanical and thermal stability of the rubber/plastic blends was characterized by UTM, DMTA, and TGA. On the addition of trans-polyoctylene rubber(TOR) to the rubber phase, there was a decrease in compression set and increase in tensile properties, hardness and dynamic properties as well as thermal stability or the elastomeric blends. Improvements in the properties were believed to be due to an increase in crosslink density of the rubber phase and increase in homogeneity of the blends.