• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.199-204
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• 2010

The objective of this paper is to present new binder systems that can be applied in composite rocket propellants, to improve properties of these propellants not only for better performance, but also to reduce waste and pollution. These novel systems are based on the thermoplastic elastomer (TPE) binders, which consists of copolymers with the addition of a plasticizer, and additives. The effect of the novel TPE binder systems on the burning rate and mechanical properties of AP based propellants was studied. The results show that propellants based on the novel TPE binders have a better energy performance than today's workhorse hydroxyl terminated polybutadine/ammonium perchlorate propellant, exhibit a similar range of burning rate, possess appropriate mechanical properties, and exhibit good processing and aging characteristics at low cost.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.279-282
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• 2008

고체 로켓 추진제로 널리 사용되는 물질은 AP/HTPB 복합추진제이다. 고체 로켓 주위에 열 하중이 가해진다면(화재 등) 추진제가 발화할 수 있고, 사고의 원인이 된다. 본 연구에서는 AP/HTPB 복합추진제의 주위에 열 하중을 가함으로써 AP/HTPB의 발화특성을 확인해 보았다.

• 한국추진공학회지
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• 제24권3호
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• pp.41-46
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• 2020

본 연구에서는 당 논문과 동일한 제목 하에 이루어진 연구결과에 이어서 최신 개발 고에너지 열가소성(ETPE)추진제의 시차 주사 열량(DSC) 및 열중량 분석(TGA)법으로 열분석을 진행하여 고에너지 열가소성 추진제의 특징을 확인하였으며, 추진제 둔감성을 확인하기 위해 추진제 둔감 정도 확인 시험인 LSGT, 파쇄성 시험을 진행하였다. 추진제 원료로는 GAP(Glycidyl Azide Polymer)이 45% 함유된 고에너지 열가소성(ETPE) 바인더와 고에너지 가소제(DEGDN), 산화제로는 AP(Ammonium Perchlorate)와 RDX(research development explosive, cyclotrimethylenetrinitramine)를 사용하였다. 위와 같은 분석을 통해, 개발된 ETPE 추진제가 일반적인 RDX/AP 추진제와 유사한 열적 거동을 갖는 것을 확인 하였다.

• 공업화학
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• 제26권2호
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• pp.145-153
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• 2015

Solvent/anti-solvent법으로 제조된 $Cr_2O_3$/과염소산암모늄 에너지 복합체의 X선 회절 분석 결과 $Cr_2O_3$이 내포된 과염소산암모늄 입자는 순수한 과염소산암모늄과 동일한 결정 구조로 확인되었으며 주사전자현미경 사진으로부터 측정된 입방체 형상 결정의 평균입도는 약 $2.5{\mu}m$이었다. 복합체의 열중량 분석으로부터 $Cr_2O_3$에 의해 과염소산암모늄의 고온 분해 영역 분해 온도가 낮아짐을 알 수 있었고, 복합체 분해 반응의 활성화 에너지는 Starlink 방법에 의해 계산되었다. 이와 같은 활성화 에너지의 변화로 인하여, 과염소산암모늄의 분해 반응 메카니즘은 전환율 약 0.25까지는 주로 핵생성에 의한 다공성 구조가 생성되면서 분해되는 것으로 보이며, 전환율 0.3 이상에서는 과염소산암모늄의 격렬한 분해 반응이 승화보다 우선하는 것으로 보인다.

• Bulletin of the Korean Chemical Society
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• 제11권4호
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• pp.276-281
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• 1990

The equivalent conductance of univalent cation (potassium, silver, thallium and ammonium) perchlorates in methanol containing 18-membered crown ethers, 18-crown-6 (18C6) and 1,10-dithia-18-crown-6 (DT18C6) were measured at different temperatures. The equivalent conductances of ammonium perchlorate were increased by increasing content of DT18C6 exceptionally, due to more favorable solvations than complexations. From the equivalent conductance changes, the formation constants for 1:1 compmlexes have been determined, and the values of enthalpy and entropy changes have been calculated. The complexations of 18C6 and DT18C6 with the univalent cations under investigation are all exothermic and the ${\Delta}$S values are all negative and no considerable differences around 50 J/ (k mol). The selectivity order of 18C6 is $K^+ > Tl^+ > Ag^+ > NH_4^+$, while that of DT18C6 is $Ag^+ > Tl^+ > NH_4^+ > K^+$. By sulfur substitutions in 18C6 result in significant decrease in stability, but the stability of $Ag^+$-DT18C6 complex are $10^4$ times larger than those of $K^+$. This increase of stabilities for $Ag^+$-DT18C6 complex are primary due to the result of favorable exothermic heat of reaction between the polarizable soft cation and soft sulfur centers. In NMR experiment, the stepwise additions of cation perchlorates into crown ether solutions induced two major spectral changes. First, the resonance all shift down field and the cation induced shifts were linear up to 1:1 cation/crown ratio, above which no further changes were observed. On the basis of these results, it could be concluded that 1:1 complex is formed. Second, the magnitudes of cation induced shifts were different each other in same ligand. By addition of silver ion to the solution of DT18C6, the largest shift of proton peak near the sulfur atom was observed. These effects are also arisen from the results of covalent bonding between "soft-soft" interactions.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1329-1334
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• 2006

The electrochemical reduction of coumarin, 7-acetoxy-4-methyl coumarin (AMC), and 7-acetoxy-4-bromomethyl coumarin (ABMC), in 0.1 M tetraethyl ammonium perchlorate/acetonitrile solution was carried out by direct current, differential pulse polarography, cyclic voltammetry, and controlled potential coulometry. The electrochemical reduction of ABMC was proceeded through three steps of electron transfer coupled with the chemical reactions. The color of solution was changed to yellow when the carbonyl group was reduced during 2nd step (-1.8 volts) and independented with cleavage of bromo group. Highest fluorescence intensity showed when the electrochemical reduction of AMC was controlled at near the potential (-2.3 volts vs. Ag/AgCl).

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.2961-2965
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• 2012

Mesoporous carbons with tailored pore size were prepared by using sucrose as the carbon source and silicas as the templates. The silica templates were obtained from a hydroxypropyl-${\beta}$-cyclodextrin-silica hybrids using ammonium perchlorate oxidation at different temperatures to remove the organic matter. The structures and surface chemistry properties of these carbon materials were characterized by $N_2$ adsorption, TEM, SEM and FTIR measurements. The catalytic performances of these carbon materials were investigated through the reduction of nitroaromatic using hydrazine hydrate as the reducing agent. Compared with other carbon materials, such as active carbon, and carbon materials from the silica templates obtained by using calcination to remove the organic matter, these carbon materials exhibited much higher catalytic activity, no obvious deactivation was observed after recycling the catalyst four times. Higher surface area and pore volume, and the presence of abundant surface oxygen-containing functional groups, which originate from the special preparation process of carbon material, are likely responsible for the high catalytic property of these mesoporous carbon materials.

• 분석과학
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• 제18권1호
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• pp.89-95
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• 2005

Studies on the electrochemical reduction of 7-acetoxy-4-bromomethyl-coumarin (ABMC), 7-acetoxymethyl coumarin (AMC), and coumarin in 0.1 M tetraethyl ammonium perchlorate acetonitrile solution were carried out with direct current, differential pulse polarography, cyclic voltammetry, and controlled potential coulometry. The electrochemical reduction of ABMC was proceeded through three irreversible steps coupled with the chemical reactions. The solution color was changed to yellow when the carbonyl group was reduced during second step and the color change was independent with bromo group of ABMC. Fluorescent intensity was highest when the electrochemical reduction was controlled at near the overpotential of supporting electrolyte (-2.3 volts).

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.27-31
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• 2003

A Polythiophene-quinoline/glassy carbon (PTQ/GC) modified electrode was developed for the determination of trace mercury in industrial waste water, natural water, soil, and other media. The electrode was prepared by the cyclic voltammetric polymerization of thiophene and quinoline on glassy carbon (GC) electrode by the potential application from -0.6 V to +2.0 V (50 mV/sec) in a solution of 0.1 M thiophene, quinoline and tetrabutyl ammonium perchlorate (TBAP) in acetonitrile. Optimum thickness of the polymer membrane on the GC electrode was obtained with 20 repeated potential cyclings. The redox behavior of Cu(Ⅱ) and Hg(Ⅱ) were almost identical on this electrode. The addition of 4-(2-pyridylazo)resorcinol (PAR) to the solution containing Cu(Ⅱ) and Hg(Ⅱ) allowed the separation of the components due to the formation of the Cu(Ⅱ)-PAR complex reduced at -0.8V, which was different from the Hg(Ⅱ) reduced at -0.5 V on a saturated calomel electrode (SCE). The calibration graph of Hg(Ⅱ) shows good linear relationship with the correlation factor of 0.9995 and the concentration gradient of 0.33 ㎂/㎠/ppb down to 0.4 ppb Hg. The method developed was successfully applied to the determination of mercury in samples such as river, waste water, and sea water.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.989-998
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• 2010

The titled dye of DBPI gives amplified spontaneous emission (ASE) with maximum at 580 nm upon pumping by nitrogen laser (${\lambda}_{ex}\;=\;337.1\;nm$). The ground state absorption cross section (${\sigma}_A$) and emission cross section (${\sigma}_E$) as well as effective emission cross section(${\sigma}^*_E$) have been determined. The electronic absorption spectra of DBPI were measured in ethanol and tetrahydrofuran at room and low temperature. DBPI displays molecular aggregation in water. The photochemical reactivity of DBPI was also studied in carbon tetrachloride upon irradiation with 525 nm light. The electrochemical investigation of DBPI dye has been carried out using cyclic voltammetry and convolution deconvolution voltammetry combined with digital simulation technique at a platinum electrode in 0.1 mol/L tetrabutyl ammonium perchlorate (TBAP) in two different solvents acetonitrile ($CH_3CN$) and dimethylformamide (DMF). The species were reduced via consumption of two sequential electrons to form radical anion and dianion (EE mechanism). In switching the potential to positive direction, the compound was oxidized by loss of two sequential electrons, which were followed by a fast dimerization and/or aggregation process i.e $EC_{dim1}EC_{dim2}$ mechanism. The electrode reaction pathway and the chemical and electrochemical parameters of the investigated compound were determined using cyclic and convolutive voltammetry. The extracted electrochemical parameters were verified and confirmed via digital simulation method.