• Journal of Hydrogen and New Energy
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• v.33 no.5
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• pp.574-582
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• 2022

A lithium-ion battery exhibits high energy density but has many limitations due to safety issues. Currently, as a solution for this, research on solid state batteries is attracting attention and is actively being conducted. Among the solid electrolytes, sulfide-based solid electrolytes are receiving much attention with high ion conductivity, but there is a limit to commercialization due to the relatively high price of lithium sulfide, which is a precursor material. This study focused on the possibility of relatively inexpensive and light lithium hydride and conducted an experiment on it. In order to analyze the characteristics of LiAlH₄, ion conductivity and thermal stability were measured, and a composites mixed with PVDF, a representative polymer electrolyte, was synthesized to confirm a change in characteristics. And metallurgical changes in the material were performed through XRD, SEM, and BET analysis, and ion conductivity and thermal stability were measured by EIS and LFA methods. As a result, Li₃AlH₆ having ion conductivity higher than LiAlH₄ is formed by the synthesis of composite materials, and thus ion conductivity is slightly improved, but thermal stability is rapidly degraded due to structural irregularity.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.181-186
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• 2008

2,5-Di-(2'-hydroxyethoxy)-4'-nitrostilbene (3) was prepared and polycondensed with terephthaloyl chloride, adipoyl chloride, and sebacoyl chloride to yield novel T-type polyesters (4-6) containing the NLO-chromophores dioxynitrostilbenyl groups, which constituted parts of the polymer backbones. Polymers 4-6 are soluble in common organic solvents such as acetone and N,N-dimethylformamide. They showed thermal stability up to 260 oC in thermogravimetric analysis with glass-transition temperatures obtained from differential scanning calorimetry in the range 90-95 oC. The second harmonic generation (SHG) coefficients (d33) of poled polymer films at the 1064 nm fundamental wavelength were around 1.42 ´ 10-9 esu. The dipole alignment exhibited high thermal stability up to 5 oC higher than glass-transition temperature (Tg), and there was no SHG decay below 100 oC due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications.

• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.226-232
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• 1990

The degradation phenomena and thermal stability of 2.5Y-TZP at low-temperature were studied by means of XRD, Raman spectra and microstructural analysis. The degradation of heat-treated 2.5Y-TZP at 20$0^{\circ}C$-20hr in air was observed on the TZP surface, be caused by the cracks generated from tlongrightarrowm transformation, and the cracks was propagated inside the polycrystalline body. The ZrO2 grain boundaries and grains near the crack were revealed as if these were diffused and dissolved. And it was also observed mlongrightarrowt transformation as the degraded TZP was refired at 140$0^{\circ}C$, and it was thought to be the fact that the moisture in atmosphere during the aging process contributed to the degradation. The thermal stability of 2.5Y-TZP was improved dramatically with an addition of 3w/o CeO2 or a provision of high Y2O3 concentration on the TZP surface.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.2
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• pp.59-65
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• 2018

We conducted an isothermal slow cook-off(ISCO) test for an aluminized explosive containing AP. The sample bulged before the run-away reaction, and therefore we were unable to obtain the ISCO data. However, these phenomena did not occur for a certain AP grade, which means that the quality of the AP exerted a significant effect on the thermal stability of the explosive formulation. In this study, we investigated the thermal stability difference between a good and bad AP grade. First, we characterized the thermal properties of all APs by Differential Scanning Calorimeter(DSC) and correlated them to the ISCO phenomena. In addition to the DSC study and ISCO test, we also investigated and calculated the SADT and self-heating rate by the ARC of the different AP qualities to interpret the thermal stability of the explosive formulation. Moreover, we investigated the impurity of the AP and a preparation method to remove the included impurity and crystallization. Finally, we implemented qualification methods to identify the quality of AP by DSC using a high-pressure crucible.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.467-468
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• 2007

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.541-542
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• 2009

We have developed an image reversal photoresist with high thermal stability and electric insulating properties for the single isolation structure of OLEDs. The thermal stability and electric insulating properties are investigated and compared with those of conventional insulator and cathode separator materials. The single isolation structure using the image reversal photoresist reduces the fabrication process steps and cuts down the manufacturing cost.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1941-1944
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• 2004

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.425-428
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• 1986

A new heterocuprate containing 2-pyridyloxy ligand, lithium 2-pyridyloxy-n-butylcuprate, has shown improved thermal stability and it reacts with acid chlorides to afford the corresponding ketones in high yields. Similarly, it can be effectively utilized in conjugate addition reactions of $\alpha,\beta$-unsaturated ketones. Of synthetic significance is that the complete utilization of n-butyl group in lithium 2-pyridyloxy-n-butylcuprate has been observed.

• Textile Coloration and Finishing
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• v.32 no.2
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• pp.103-110
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• 2020

Super engineering plastic(SEP) are applied to high performance and high value industries due to their excellent mechanical properties and high continuous operating temperature. Among them, PES and PEI are amorphous SEPs, and have the advantages of high flexibility, mechanical properties, transparency, and thermal stability. In this study, polyethersulfone(PES) and polyetherimide(PEI) fibers were manufactured to produce flame retardant artificial hair. PES and PEI fibers prepared through a melt-spinning process at a high temperature of 360 to 420℃. They are compared with commercial artificial hair by thermal gravimetric analysis(TGA), linear density, tenacity, and limited oxygen index(LOI) analysis. PES and PEI fibers have similar linear density and tenacity to commercial artificial hair, while their thermal stability and flame retardant are excellent. In particular, flame retardant was analyzed through LOI value and PES was 35.1%, which is superior to commercial artificial hair PET/Br(28.2%) and PET/P(20.2%). Therefore, PES and PEI are suitable as artificial hair for flame retardant.

• Journal of Adhesion and Interface
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• v.7 no.4
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• pp.39-44
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• 2006

A new kind of silicone-epoxy composite is reported in this research. The silicone-epoxy resin was synthesized by the hydrosilylation of tetramethycyclotetrasiloxane and 4-vinyl-1-cyclohexene 1,2-epoxy with a high reaction yield. It was found that the obtained silicone-epoxy resin shows a high reactive activity to the aluminum complex-silanol catalyst. The resin could be cured under the catalysis of $(Al(acac)_3/Ph_2Si(OH)_2$ at a concentration below 0.1 wt% to give a hard cured resin showing excellent optical clarity, UV resistance and thermal stability. It was also found that the Si-H groups facilitated the curing reaction and the silicone-epoxy resin bearing Si-H group could be cured effectively even if $Ph_2Si(OH)_2h$ was absent. Moreover, the UV resistance and thermal stability were improved significantly by the introduction of Si-H groups. This is possibly due to the reductive property of Si-H groups which can annihilate radical and peroxide effectively. This kind of silicone-containing epoxy composite might have very promising applications as optical resin, optical adhesive and encapsulation materials for electronic devices.