• Title/Summary/Keyword: differential scanning calorimetry(DSC)

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Bromination of Alkyl Chlorides by LiBr and CaBr2 adsorbed on Alumina (LiBr와 CaBr2가 흡착된 알루미나상에서 일어나는 염화 알킬의 브롬화반응)

  • Park, Yeong Hoon;Shin, Young Mun;Cho, Beom Jun;Kim, Chang Bae
    • Applied Chemistry for Engineering
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    • v.7 no.5
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    • pp.1015-1019
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    • 1996
  • Several alkyl chlorides were brominated using LiBr and $CaBr_2$ adsorbed on alumina in the absence of solvent. The yields of alkyl bromides were fairly high. Such a high reactivity by these bromide salts might be due to the interaction of minute amount of water and the salt on alumina. Differential scanning calorimetry (DSC) thermogram was provided and discussed.

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Synthesis and Characterisation of Hole Transporting Materials Based on N,N,N-Tris-[4-(Naphthalen-1-yl-phenylamino)Phenyl]-N,N,N-Triphenylbenzene-1,3,5-Triamine (N,N,N-Tris-[4-(Naphthalen-1-yl-phenylamino)Phenyl]-N,N,N-Triphenylbenzene-1,3,5-Triamine을 이용한 Hole Transporting 재료의 합성)

  • Mathew, Siji;Haridas, Karickal R.
    • Journal of the Korean Chemical Society
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    • v.54 no.6
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    • pp.717-722
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    • 2010
  • Two derivatives of star shaped compounds based on naphthylamine with symmetric trisubstituted benzene as core, methoxy and ethoxy as end substitutions are synthesized. The synthesized compounds are characterized by UV-visible, FT-IR and NMR spectrometric techniques. The electronic and thermal properties of the compounds are studied using cyclic voltametry (CV) and differential scanning calorimetry (DSC) respectively. The data's obtained have similarity with the arylamines that have been already used in optoelectronic devices. So these compounds are interesting materials for applications in such devices.

Kinetics on the Thermal Decomposition of Cellulose (셀룰로오스의 열분해 반응속도론)

  • 최승찬;박영수
    • Journal of the Korean Society of Tobacco Science
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    • v.5 no.2
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    • pp.55-62
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    • 1983
  • Four of non- isothermal methods evaluating kinetics have been studied by using differential scanning calorimetry (DSC) and thermogravimetry (TG) and applied for kinetics of the thermal decomposition of cellulose. It is concluded that the heating evolution methods with DSC and approximative methods with TC can lead to satisfactory kinetic analysis. Results calculating the reacting order and the activation energy of cellulose decomposition were 1/2 order and 42kcaB/mol, respectively.

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Study of Cure Kinetics of Vacuum Bag Only Prepreg Using Differential Scanning Calorimetry (시차주사열량계를 이용한 진공백 성형 프리프레그의 경화 거동 연구)

  • Hyun, Dong Keun;Lee, Byoung Eon;Shin, Do Hoon;Kim, Ji Hoon
    • Composites Research
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    • v.33 no.2
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    • pp.44-49
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    • 2020
  • The cure kinetics of carbon fiber-reinforced prepreg for Vacuum Bag Only(VBO) process was studied by differential scanning calorimetry (DSC). The total heat of reaction (ΔHtotal = 537.1 J/g) was defined by the dynamic scanning test using prepregs and isothermal scanning tests were performed at 130℃~180℃. The test results of isothermal scanning were observed that the heat of reaction was increased as the temperature elevated. The Kratz model was applied to analyze the cure kinetics of resin based on the test results. To verify the simulation model, the degree of cure from panels using different cure cycles were compared with the measurement. The simulation model showed that the error against the experimental value was less than 3.4%.

Differential Scanning Calorimetry of Rice Starch (쌀 전분의 Differential Scanning Calorimetry)

  • Hyun, Chang-Kee;Park, Kwan-Hwa;Kim, Young-Bae;Yoon, In-Hwa
    • Korean Journal of Food Science and Technology
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    • v.20 no.3
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    • pp.331-337
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    • 1988
  • The thermal properties of typical five Indica and five Japonica rice varieties were investigated by Differential Scanning Calorimetry (DSC). There was no significant difference in gelatinization temperature between Indica and Japonica varieties, but the average enthalpy of gelatinization was larger in Indica types than that in Japonica. However, the enthalpy of melting of amylose-lipid complex was larger in Japonica types than that in Indica types. The DSC thermogram of hydrolyzed rice residue included a smaller peak of gelatinization with narrow range of temperature. Retrogradation of gelatinized rice kernel was also determined with DSC theremograms. The endothermic peak areas clearly increased with increasing storage time at $4^{\circ}C$ so that the area could be used as a measure of the relative degree of retrogradation. The results indicated that Samgang variety(Indica) retrograded more rapidly than Chuncheong variety(Japonica).

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Study of the Curing Reaction Rate of a Glass Fiber Reinforced Bisphenol-A (BPA) Epoxy Prepreg by Differential Scanning Calorimetry (DSC) (Differential Scanning Calorimetry (DSC)를 이용한 유리섬유 Bisphenol-A(BPA)계 에폭시 프리프레그의 경화 반응 속도 연구)

  • Kwon, Hyeon-Jin;Park, Hee-Jung;Lee, Eun-Ju;Ku, Sang-Min;Kim, Seon-Hong;Lee, Kee-Yoon
    • Composites Research
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    • v.31 no.1
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    • pp.30-36
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    • 2018
  • The curing behavior of glass fiber reinforced epoxy prepregs based on Bisphenol-A (BPA) was studied by differential scanning calorimetry (DSC). The total heat of reaction(${\Delta}H_{total}=280.3J/g$) was determined based on the results of the dynamic heating scanning experiments. Isothermal experiments were carried out at $110{\sim}130^{\circ}C$, and it was observed that the maximum conversion and the maximum reaction rate were increased as temperature increased. Also Kamal equation was applied to analyze autocatalytic reaction of epoxy prepregs. The higher temperatures, the greater reaction rate constants ($k_1$, $k_2$). Theoretical values were calculated by these reaction rate constants and compared with experimental values. And it was confirmed that they were in reasonable agreement. At the beginning of the reaction, the experimental data and theoretical prediction were shown the same tendency, but at the end of reaction, the experimental data were smaller than theoretical predicted values due to reaction rates controlled by diffusion.

Freezing Behaviors of Frozen Foods Determined by $^1H$ NMR and DSC

  • Lee, Su-Yong;Moon, Se-Hun;Shim, Jae-Yong;Kim, Yong-Ro
    • Food Science and Biotechnology
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    • v.17 no.1
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    • pp.102-105
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    • 2008
  • The freezing patterns of commercial frozen foods were characterized by using proton nuclear magnetic resonance ($^1H$ NMR) relaxometry and differential scanning calorimetry (DSC). The liquid-like components like unfrozen water were investigated as a function of temperature (10 to $-40^{\circ}C$) and then compared with the unfrozen water content measured by DSC. The formation of ice crystals and the reduction of water in the foods during freezing were readily observed as a loss of the NMR signal intensity. The proton NMR relaxation measurement showed that the decreasing pattern of the liquid-like components varied depending on the samples even though they exhibited the same onset temperature of ice formation at around $0^{\circ}C$. When compared with the unfrozen water content obtained by the DSC, the NMR and DSC results could be closely correlated at the temperature above $-20^{\circ}C$. However, the distinct divergence in the values between 2 methods was observed with further decreasing temperatures probably due to the solid glass formation which was not detected by DSC.

Cure Kinetics of Diglycidyl ether of bisphenol A-Methylene dianiline-Succlnonitrile System (Diglycidyl ether of bisphenol A/Methylene dianiline/Succinonitrile계의 경화반응 속도론)

  • Jo, Seong-U;Sim, Mi-Ja;Kim, Sang-Ok
    • Korean Journal of Materials Research
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    • v.2 no.4
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    • pp.257-262
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    • 1992
  • The cure kinetics of a diglycidyl ether of bisphenol A (DGEBA) with 4, 4'-methylene dianiline (MDA) added succinonitrile was studied through the dynamic run method by applying the data to the Kissinger equation which analyses the effect of the heating rate on the temperature at maximum reaction rate using Differential Scanning Calorimetry (DSC) analyzer in the range of 3$0^{\circ}C$-35$0^{\circ}C$. In the DGEBA/MDA system with SN, the activation energy ($E_a$) and the pre-exponential factor (A) were calculated. From these results, the rate constants (k) were obtained according to the different SN contents.

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The Thermotropic Phase Behaviors of Artificial Phospholipid Liposomes Incorporated with Soyasaponin (대두사포닌이 침투된 인공 인지질 생체유사막의 열에 의한 상변화에 관한 연구)

  • Kim, Nam-Hong;Roh, Sung-Bae
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.22 no.3
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    • pp.323-327
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    • 1993
  • The effect of soyasaponin on the liposomal phospholipid membrane was investigated by differential scanning calorimetry (DSC). Soyasaponins were obtained and the enthalpy changes and the sizes of cooperative unit of the transition were calculated. The thermograms of L-$\alpha$-dimyristoyl phosphatidylcholine (DMPC) incorporated with soyasaponin showed that the phase transition temperature was significantly lowered and the peak was broadened. This was attributed to the possibility that incorporation of soyasaponin into the lipid bilayers reduced the cooperative unit of phospholipid bilayers. These results indicate soyasaponin might have significant effect on the fluidity of biological membrane.

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The Thermal Stability Analysis of Fumes and Mists During the Drying Process of a PCB (PCB 건조공정의 흄과 미스트에 대한 열안정성 분석)

  • Chu, Chang Yeop;Lee, Jung Suk;Baek, Jong Bae
    • Journal of the Korean Society of Safety
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    • v.34 no.4
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    • pp.32-40
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    • 2019
  • During the manufacturing process of a printed circuit board(PCB), fumes and mists are generated as the ink dries on the PCB surface. The generated fumes and mists are deposited in the dryer wall and the exhaust duct. Deposited fumes and mists may present a fire hazard if the dryer temperature control system fails. In this study, the thermal stability of the fumes and mists deposited in the dryer and ducts has been analyzed by experimental methods such as thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), auto ignition temperature (AIT), and multiple mode calorimetry(MMC). According to the experimental analyses, experimental samples are likely to generate gas at the temperature ($180{\sim}240^{\circ}C$) that deviates from the normal operating temperature ($150{\sim}156^{\circ}C$). It has been shown that the thermal stability is degraded when the temperature is deviated from the normal operating temperature. In the end, engineering and management safety measures of accidental prevention have been suggested.