• Journal of Aerospace System Engineering
• /
• v.7 no.4
• /
• pp.36-41
• /
• 2013

In order to improve incombustibility of EPDM(Ethylene propylene diene monomer)-based rubber, inorganic materials as $Al(OH)_3$ and $Sb_2O_3$ were added. The mechanical and thermal properties have been measured for vulcanized rubber loaded with different concentrations of $Al(OH)_3$ and $Sb_2O_3$. As inorganic material contents increases from 5phr to 30phr, the specific gravity and hardness increase while elongation at break decreases. This study performed incombustibility test and thermal analysis through TGA(Thermogravimetric Analyzer). As a results, incombustible and thermal properties of EPDM-based rubber were improved as $Al(OH)_3$ and $Sb_2O_3$ contents increase.

• Carbon letters
• /
• v.5 no.3
• /
• pp.113-117
• /
• 2004

The mesophase pitch was prepared by adding 1~10 wt% of the borane-pyridine complex (BPC) to decant oil. It was prepared in a reactor held at $450^{\circ}C$ for 2 h in $N_2$ atmosphere. The mesophase pitches were analyzed using thermogravimetric analyzer (TGA), melting point apparatus, X-ray diffraction (XRD) and polarized optical microscope. The coke yield, softening point, toluene insoluble, density and content of anisotropy in the mesophase pitches were increased with BPC contents. The XRD profiles did not show any effect of addition of BPC on the formation of mesophase pitch, while the crystallinity of mesophase pitches was increased when the materials were heat treated with boron compound.

• Applied Chemistry for Engineering
• /
• v.3 no.3
• /
• pp.464-470
• /
• 1992

The copolyester was prepared by melt polycondensation varying the amount of ethylene glycol(EG) and pentanediol from terephthalic acid(TPA), EG and pentanediol isomers were. used as the third monomer. The chemical structure and the compositions of the copolyester were determined by nuclear magnetic resonance spectroscopy. Thermal properties were investigated with the aid of differential scanning calorimetry and thermogravimetric analyzer.

• Korean Chemical Engineering Research
• /
• v.58 no.1
• /
• pp.142-149
• /
• 2020

In this study, the electrochemical performance of Graphite/Silicon/Pitch composites as anode material was investigated to improve the low theoretical capacity of artificial graphite. Spherical artificial graphite surface was coated with polyvinylpyrrolidone (PVP) amphiphiles material to synthesize Graphite/Silica material by silica islands growth. The Graphite/Silicon/Pitch composites were prepared by petroleum pitch coating and magnesiothermic reduction. The Graphite/Silicon/Pitch composite electrodes manufactured using poly(vinylidene fluoride) (PVDF), carboxymethyl cellulose (CMC) and polyacrylic acid (PAA) binders. The coin type half cell was assembled using various electrolytes and additives. The Graphite/Silicon/Pitch composites were analysed by X-ray diffraction (XRD), scanning electron microscope (SEM) and a thermogravimetric analyzer (TGA). The electrochemical characteristics of Graphite/Silicon/Pitch composite were investigated by constant current charge/discharge, rate performance, cyclic voltammetry and electrochemical impedance spectroscopy. The Graphite/Silicon/Pitch composites showed high cycle stability at a graphite/silica/pitch ratio (1:4:8 wt%). When the electrode is prepared using PAA binder, the high capacity and stability is obtained. The coin type half cell assembled using EC: DMC: EMC electrolyte showed high initial capacity (719 mAh/g) and excellent cycle stability. The rate performance has an capacity retention (77%) at 2 C/0.1 C and an capacity recovery (88%) at 0.1 C / 0.1 C when the vinylene carbonate (VC) was added.

• Clean Technology
• /
• v.29 no.3
• /
• pp.185-192
• /
• 2023

This study was conducted to obtain basic process simulation data before conducting pyrolysis experiments for the development of a thermochemical conversion system by recirculation of heat carrier and gases thereby. In this study, polypropylene (PP) was used as a pyrolysis sample material as an alternative to waste plastics, and fluid sand was used as a heat transfer medium in the system. Manganese (Mn) was chosen as the catalyst for the pyrolysis experiment, and the catalyst pyrolysis was performed by impregnating it in the sand. The basic properties of PP were analyzed using a thermogravimetric analyzer (TGA), and liquid oil was generated through catalytic pyrolysis under a nitrogen atmosphere at 600℃. The carbon number distribution of the generated liquid oil was confirmed by GC/MS analysis. In this study, the effects of the presence and the amount of Mn loading on the yield of liquid oil and the distribution of hydrocarbons in the oil were investigated. When Mn/sand was used, the residue decreased and the oil yield increased compared to pyrolysis using sand alone. In addition, as the Mn loading increased, the ratio of C₆~C₉ range gasoline in the liquid oil gradually increased, and the distribution of diesel and heavy oil with more carbon atoms than C₁₀ in the oil decreased. In conclusion, it was found that using Mn as a catalyst and changing the amount of Mn could increase the yield of liquid oil and increase the gasoline ratio in the product.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.5
• /
• pp.1125-1129
• /
• 2008

Polypropylene (PP)/corn starch master batch(starch-MB) blends with different PP compositions of 90, 80, 70, and 60 wt% were prepared by melt compounding at $200^{\circ}C$, using lab scale Brabender mixer. The chemical structures, thermal properties and non-isothermal crystallization behavior of the PP/starch-MB blends were investigated by FT-infrared spectrometry (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). The fabrication of the PP/starch-MB blend was confirmed by the existence of hydroxy group in FT-IR spectrum. There was no district change in melting temperature and melting enthalpy, and TGA curve indicates a decrease in degradation temperature with starch-MB content. The non-isothermal crystallization process was analyzed using by Avrami equation. The Avrami exponents were in the range of 2.71-3.97 for PP and 1.48-1.99 for PP/starch-MB blonds. The activation energies calculated by Kissinger method were 233 kJ/mol for PP, 484 kJ/mol for PP90, 541 kJ/mol for PP80, 553 kJ/mol for PP70, and 422 kJ/mol for PP60.

• Transactions of the Korean hydrogen and new energy society
• /
• v.22 no.2
• /
• pp.168-177
• /
• 2011

A set of kinetics study on the reduction with $CH_4$, oxidation with steam and oxidation with air was performed for $Fe_2O_3/ZrO_2$. $Fe_2O_3/ZrO_2$ was prepared by aerial oxidation method. The reactivity experiments were performed in a thermogravimetric analyzer (TGA) with different reacting gas concentrations and temperatures. The obtained activation energy of reduction by methane, oxidation by water and oxidation by air are 219 kJ/mol, 238 and 20 respectively.

• Korean Chemical Engineering Research
• /
• v.47 no.6
• /
• pp.676-682
• /
• 2009

Devolatilization of the Refuse Derived Fuel(RDF) which is produced at WonJu in Korea was characterized in air atmosphere with variation of heating rate(10, 20 and $30^{\circ}C/min$) in TGA. The results of TG Analysis have shown that the pyrolysis and char combustion of the RDF occurred in the range of $350{\sim}700^{\circ}C$ depending on the heating rate. Activation energy of the RDF which was determined by using Friedman and Ozawa-Flynn-Wall method was in the range of 14.44~18.40 kcal/mol. Also, reaction order(n) and pre-exponential factors(A) were 1.219 and $3.02{\times}10^5$ by using Friedman method, respectively. In order to find out the devolatilization mechanism of the RDF, twelve solid-state mechanisms defined by Coats Redfern Method were tested. The results of the Coats Redfern Method have shown that chemical reaction is the effective mechanism by comparison with the value of the activation energy which was derived from the Friedman and Flynn-Wall-Ozawa method and correlation coefficient from twelve solid-state mechanisms of Coats Redfern Method. The solid state decomposition mechanism of the RDF was found to be a decelerated $F_1$ type, random nucleation with one nucleus on the individual particle.

• Korean Chemical Engineering Research
• /
• v.50 no.3
• /
• pp.391-397
• /
• 2012

The depletion of conventional oil reserves and the increasing energy need in developing countries such as China and India result in exceeding oil demand over supply. As a solution of the problem, the efficient utilization of heavy oil has been receiving more and more interest. In order to utilize heavy oil, upgrading processes are required. Among the upgrading processes, thermal decomposition is thought to be relatively simple and economical. In this study, to understand basic characteristics of thermal decomposition of heavy oil, we conducted pyrolysis experiments of deasphalted oil (DAO) produced by a solvent deasphalting process. DAO is a mixture of many components and consists mainly of materials of carbon number 20~40. For the comparison with results of DAO pyrolysis, additional pyrolysis experiments with single materials of carbon number 30 ($C_{30}H_{62}$, $C_{30}H_{58}O_4S$, $C_{30}H_{63}O_3P$) were conducted. Pyrolysis experiments were carried out non-isothermally with variation of heating rate (10, 50, $100^{\circ}C$/min) in a thermogravimetric analyzer. Average pyrolysis activation energy determined by using Arrhenius method, Ingraham and Marrier method, and Coats and Redfern method was 72~99 kJ/mol. In the activation energy calculated by Ozawa-Flynn-Wall method, DAO had wider variation than other single materials.

• Korean Journal of Food Science and Technology
• /
• v.37 no.4
• /
• pp.567-573
• /
• 2005

Compatability of films made of chitosan, gelatin, and their blends prepared by aqueous solution casting was investigated using a thermogravimetric analyzer(TGA) and a dynamic mechanical analyzer (DMA). TGA showed gelatin is more thermally stable than chitosan, and thermal stability of chitosan in blends was higher than that of pure chitosan due to interaction among functional groups of component polymers in blend. Glass transition temperature $(T_g)$ of blends was dependent on chitosan content of blends. Blend films exhibited good miscibility. Moisture and glycerol contents of blend strongly affected thermal properties of two component polymers.