• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.28-29
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• 2006

To improve Mechanical and Thermal Properties of semiconducting materials in power cable, we have investigated those of semiconducting materials showed by changing the content of carbon black and Carbon Nanotube. Density were measured by EW-200SG. High temperature, heat degradation initiation temperature, and heat weight loss were measured by TGA (Thermogravimetric Analysis). The dimension of measurement temperature was $0[^{\circ}C]$ J to $700[^{\circ}C]$, and rising temperature was $10[^{\circ}C/min]$. Heat degradation initiation temperature from the TGA results was decreased according to increasing the content of Carbon Nanotube. That is, heat stabilities of EVA containing the weak VA (vinyl acetate) against heat was measured the lowest. From the results of the experiment applied in this study, it is evident that a small amount of Carbon nanotube additives significantly improved the Mechanical and Thermal Properties of semiconducting materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.133-137
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• 2004

In this paper, we investigated impurities content, absorption properties, and thermal properties showing by changing the content of carbon black which is semiconductive materials for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Impurities content of specimens and absorption properties were measured by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer) and Karl Fisher. And high temperature, heat degradation initiation temperature, and heat weight loss were measured by TGA (Thermogravimetric Analysis). The dimension of measurement temperature was 0$[^{\circ}]$ to 800$[^{\circ}]$, and rising temperature was 10$[^{\circ}/min]$. Impurities content was highly measured according to increasing the content of carbon black from this experimental result also absorption amount was increased according to these properties. Specially, impurities content values of the A1 and A2 of existing resins were measured more than 4000[ppm]. Heat degradation initiation temperature from the TGA results was decreased according to increasing the content of carbon black. All over, heat stabilities were EEA>EBA>pEVA. That is, heat stabilities of EVA containing the weak VA(vinyl acetate) against heat was measured the lowest.

• Journal of Pharmaceutical Investigation
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• v.27 no.3
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• pp.233-239
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• 1997

Glibenclamide is a second generation sulfonylurea that is orally active as a hypoglycemic drug. It exists as a crystalline powder which is sparingly soluble in water. It was investigated that the potential of glibenclamide to exhibit polymorphism. Three polymorphic modifications (form 1, form 2 and form 3) and three pseudopolymorphic modifications (form 4, form 5 and form 6) were obtained by crystallization from different organic solvents. The isolated crystal forms were characterized by differential scanning calorimetry(DSC), thermogravimetric analysis(TGA) and X-ray crystallography powder diffraction studies. Form 1 was the most stable and melt at $175.4^{\circ}C$. Form 2 was metastable and melt at $151.0^{\circ}C$. Form 3 was a new polymorphic modification because it was different from form 1 and form 2 in X-ray crystallography powder diffraction data. Form 4 was a 1 : 7(toluene : glibenclamide) toluene solvate; form 5 was a 1 : 5(toluene : glibenclamide) toluene solvate; form 6 was a 3 : 8(pentanol : glibenclamide) pentanol solvate. All forms were stable in 3-month storage under 0% or 100% humidity condition. The dissolution rate of form 4 was highest; those of form 2, form 3, form 1, form 5 and form 6 followed.

• Polymer(Korea)
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• v.38 no.1
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• pp.108-112
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• 2014

Novel adhesive polyaspartamides containing catechol and primary amine pendent groups were synthesized through successive ring-opening aminolysis reactions of dopamine (DOP) and ethylenediamine (EDA) with polysuccinimide (PSI). The oxidative gelation of aqueous dopamine-modified polyaspartamide was observed by adding $NaIO_4$ as the oxidizing reagent. FTIR, UV-vis and oscillatory rheometry was used to elucidate the oxidative cross-linking toward gel formation. The prepared gel was characterized by the swelling degree, thermogravimetric analysis (TGA), and by scanning electronic microscopy (SEM).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.5
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• pp.403-406
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• 2019

We prepared yarned carbon nanotube (CNT) fibers from a CNT forest synthesized on a Si wafer by chemical vapor deposition (CVD). The yarned CNT fibers were thermally annealed to reduce their resistance by removing the amorphous carbonaceous impurities present in the fibers. The resistance of the yarned CNT fiber gradually decreased with an increase in the annealing temperature from $200^{\circ}C$ to $400^{\circ}C$ but increased again above $450^{\circ}C$. We carried out thermogravimetric analysis (TGA) to confirm the burning properties of the amorphous carbonaceous impurities and the crystalline CNTs present in the fibers. The pattern of the mass change of the sample CNT fibers was very similar to that of the resistance change. We conclude that CNT fibers should be thermally annealed at temperatures below $400^{\circ}C$ for reducing and stabilizing their resistance.

• Composites Research
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• v.34 no.3
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• pp.180-185
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• 2021

Due to the formation of random three dimensional network structure, which cause a lot of scattering of phonons, the thermal conductivity is low when the liquid crystalline epoxy is cured with amine-based curing agent. This problem is solved by using a cationic initiator that can make mesogen groups to be stacked structure. In this experiment, the thermal stability is compared by investigating the activation energy of isothermal decomposition through TGA of an epoxy using an amine-based curing agent and a cationic initiator. As a result, the energy of the activation of the epoxy using a cationic initiator is high. Compared with the previous experiments, the thermal stability is similar to the thermal conductivity.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.3
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• pp.202-208
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• 2022

Pt-Ni nanocatalysts were loaded on carbon black by spontaneous reduction reaction of platinum (II) acetylacetonate and nickel (II) acetylacetonate, and they were characterized by transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), energy dispersive x-ray analyzer (EDS), BET surface area and fuel cell test station. The distribution of the Pt and Ni nanoparticles was observed by TEM, and the loading weight of Pt-Ni nanocatalysts on the carbon black was measured by TGA. The elemental ratio of Pt and Ni was estimated by EDS. It was found that the loading weight of Pt-Ni nanoparticles was 5.54 wt%, and the elemental ratio of Pt and Ni was 0.48:0.35. Specific surface area was measured by BET analysis instrument and I-V characteristics were estimated.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.715-722
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• 2022

Pt-Fe/carbon black nanocatalysts were prepared by spontaneous reduction reaction of Platinum(II) acetylacetonate and Iron(II) acetylacetonate in a nucleophilic solvent and they were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analyzer (EDS), thermogravimetric analyzer (TGA), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) surface area analysis and anion exchange membrane (AEM) water electrolysis test station. The distribution of the Pt and Fe nanoparticles on carbon black was observed by TEM, and the loading weight of Pt-Fe nanocatalysts on the carbon black was measured by TGA. Elemental ratio of Fe:Pt was estimated by EDS and it was found that elemental ratio of Pt and Fe was changed in the range of 1:0 to 0:1, and the loading weight of Pt-Fe nanoparticles on the carbon black was 5.95-6.78 wt%. Specific surface area was greatly reduced because Pt-Fe nanocatalysts blocked the pores. I-V characteristics were estimated.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.1091-1099
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• 2024

Fluoride-salt-cooled High-temperature Reactor (FHR) is a promising nuclear reactor technology. Among many challenges presented by the molten fluoride salts is the corrosion of salt-facing structural components. Higher moisture contents, in the FLiNaK (LiF-NaF-KF, 46.5-11.5-42 mol%) salt, aggravate intergranular corrosion and pitting for the given alloys. Therefore, several thermal dehydration tests of FLiNaK salt were performed with a batch size suitable for thermal-hydraulic experiments. Thermogravimetric Analysis (TGA) was performed for the three constituent fluoride salts individually. Preliminary thermal dehydration plans were then proposed for NaF and KF salts based on the TGA curves. However, the dehydration process may not be required for LiF since its low mass loss (<1.3 wt%). To evaluate the performance of these thermal dehydration plans, a batch-scale salt dehydration test facility was designed and constructed. The preliminary thermal dehydration plans were tested by varying the heating rates, target temperature, and holding time. The sample mass loss data showed that the high temperatures (>500 ℃) were necessary to remove a significant amount of moisture (>1 wt%) from NaF salt, while relatively low temperatures (around 300 ℃) with a long holding time (>10 h) were sufficient to remove most of the moisture from KF salt.

• Fibers and Polymers
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• v.4 no.4
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• pp.195-198
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• 2003

Epoxidized polybutadiene (EPB) was prepared by polybutadiene (PB) with m-chloroperbenzoic acid (MCPBA) in homogeneous solution. EPB was blended with poly(3-hydroxybutyrate) (PHB) up to 30 wt% by solution-precipitation procedure. The thermal decomposition of PHB/EPB blends was studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). The thermograms of PHB/EPB blends contained a two-step degradation process, while that of pure PHB sample exhibited only one-step degradation process. This degradation behavior of PHB/EPB blends, which have a higher thermal stability as measured by maximum decomposition temperature and residual weight, is probably due to crosslinking reactions of the epoxide groups in the EPB component with the carboxyl chain ends of PHB fragments during the degradation process, and the occurrence of such reactions can be assigned to the exothermic peaks in their DTA thermograms.