• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.83-90
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• 2021

In this study, effects of the physical and chemical properties of low temperature heated carbon on electrochemical behavior as a secondary battery anode material were investigated. A heat treatment at 600 ℃ was performed for coking of petroleum based pitch, and the manufactured coke was heat treated with different heat temperatures at 700~1,500 ℃ to prepare low temperature heated anode materials. The physical and chemical properties of carbon anode materials were studied through nitrogen adsorption and desorption, X-ray diffraction (XRD), Raman spectroscopy, elemental analysis. Also the anode properties of low temperature heated carbon were considered through electrochemical properties such as capacity, initial Coulomb efficiency (ICE), rate capability, and cycle performance. The crystal structure of low temperature (≤ 1500 ℃) heated carbon was improved by increasing the crystal size and true density, while the specific surface area decreased. Electrochemical properties of the anode material were changed with respect to the physical and chemical properties of low temperature heated carbon. The capacity and cycle performance were most affected by H/C atomic ratio. Also, the ICE was influenced by the specific surface area, whereas the rate performance was most affected by true density.

• Applied Biological Chemistry
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• v.41 no.6
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• pp.451-456
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• 1998

To find out the repeated application effect of chicken and pig manure composts on tomato growth and soil physico-chemical properties, different rates of the composts were applied to greenhouse soils with low fertility for 3 years and tomato was grown annually. As application rate of compost increased, the growth and fruit yield of tomato increased markedly, and there are also a little increase in sugar content in fruit juice and weight per fruit. When only compost was applied, however, physical and chemical properties in soil showed to be unbalanced such as significantly low bulk density and hardness, and high porosity as well as high organic matter and exchangeable K content, and low exchangeable Ca content than those of optimum range for soil diagnosis. Therefore mixed use of compost and chemical fertilizer is more promising way than the only use of compost to make suitable physico-chemical properties for tomato growth.

• Macromolecular Research
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• v.15 no.6
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• pp.520-526
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• 2007

The effects of poly($({\varepsilon}$-caprolactone) (PCL) on poly(acrylonitrile-butadiene-styrene) (ABS) and polycarbonate (PC) blends were studied. Blends of ABS/PC (70/30, wt%) with PCL as a compatibilizer were prepared by a twin screw extruder. From the glass transition temperature $(T_g)$ results of the ABS/PC blends with PCL, the $T_g$(PC) of the ABS/PC (70/30) blends decreased with increasing PCL content. From the results of the morphology of the ABS/PC (70/30) blends with PCL, the phase separation between the ABS and PC phases became less significant after adding PCL in the ABS/PC blends. In addition, the morphological studies of the ABS/PC blends etched by NaOH indicated that the shape of the droplet was changed from regular round to irregular round by adding PCL in the ABS/PC blends. These results for the mechanical properties of the ABS/PC blends with PCL indicated that the tensile, flexural and impact strengths of the ABS/PC (70/30) blends peaked at a PCL content of 0.5 phr. From the results for the rheological properties of the ABS/PC (70/30) blends with PCL content, the storage modulus, loss modulus and complex viscosity increased at PCL content up to 5 phr. From the above results of the $T_g$, mechanical properties, morphology and complex viscosity of the ABS/PC blends with PCL, it was concluded that the compatibility was increased with PCL addition in the ABS/PC (70/30, wt%) blends and that the optimum concentration of PCL as a compatibilizer is 0.5 phr.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.107-116
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• 2013

PURPOSES: The liquid-type chemical warm-mix asphalt (WMA) additive has been developed. This study evaluates the basic properties of the additive and the mechanical properties of WMA asphalt and mixture manufactured by using the newly developed chemical additive. METHODS: First, the newly developed WMA additive was applied to the original asphalt by various composition of additive components and dosage ratio of additive. These WMA asphalt binders were evaluated in terms of penetration, softening point, rotational viscosity, and PG grade. Based on the binder test results, one best candidate was chosen to apply to the mixture and then the mechanical properties of WMA mixture were evaluated for moisture susceptibility, dynamic modulus, and rutting and fatigue resistance. RESULTS : According to the binder test, WMA asphalt binders showed the similar properties to the original asphalt binder except the penetraion index of WMA additive was a little higher than original binder. From the Superpave mix design, the optimum asphalt content and volumetric properties of WMA mixture were almost the same with those of hot mix asphalt (HMA) mixture even though the production and compaction temperatures were $30^{\circ}C$ lower for the WMA mixture. From the first set of performance evaluation, it was found that the WMA mixture would have some problem in moisture susceptibility. The additive was modified to improve the resistance to moisture and the second set of performance evaluation showed that the WMA mixture with modified chemical additive would have the similar performance to HMA mixture. CONCLUSIONS : Based on the various laboratory tests, it was concluded that the newly developed chemical WMA additve could be successfully used to produce the WMA mixture with the comparable performance to the HMA mixture. These laboratory evaluations should be confirmed by applying this additive to the field and monitoring the long-term performance of the pavement, which are scheduled in the near future.

• Corrosion Science and Technology
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• v.7 no.5
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• pp.269-273
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• 2008

It is known that the fluoric resin has the most outstanding properties in the extremely acidic environment of high temperature. However, this resin is the thermal hardening type that needs long time heat treatments above $250^{\circ}C$. It's impossible to use in situ in the extremely acidic environment such as a huge FGD ductworks or industrial chemical tanks. Furthermore, even the natural hardening type fluoric coatings which can be hardened less than $120^{\circ}C$ can not be applied to the highly acidic environmental plants because of its chemical resistance. In this study, new fluoric coatings that has excellent thermal resistance, chemical resistance and corrosion resistance has been developed in order to solve above problems and to be applied to the large plant structures in the field. These newly developed coatings are organic and inorganic composite type that have fluoric rubber(100 wt%), fluoric resin(5~50 wt%), oxalates(5~30 wt%), inorganic fillers mixed with plate-type and bulk-type solids(20~150 wt%), hardeners(0.5~5 wt%), and hardening hasteners(0.1~3 wt%). The best chemical and physical properties of these coatings are acquired by variation of adhesive reinforcement agents, dispersants, leveling agents. Mixing ratios of plate-type and bulk-type inorganic fillers influence the thermal properties, abrasive resistance and chemical infiltration properties of coatings. The mixing control is also very important to have homogeneous surface and removing inner voids of coatings.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.80-83
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• 2005

In this work, effects of oxygen plasma on surface characteristics of carbon fibers were investigated in mechanical properties interfacial of carbon fibers-reinforced composites. The surface properties of the carbon fibers were determined by acid/base values, FT-IR, and X-ray photoelectron spectroscopy (XPS). Also, the mechanical properties of the composites were studied in and critical stress intensity factor ($K_{IC}$) and critical strain energy release rate mode II ($G_{IIC}$) measurements. As experimental results, the $O_{lS}/C_{lS}$ ratio of the carbon fiber surfaces treated by oxygen plasma was increased compared to that of untreated ones, possibly due to development of oxygen-containing functional groups. The mechanical properties of the composites, including $K_{IC}$ and $G_{IIC}$ had been improved in the oxygen plasma on fibers. These results could be explained that the oxygen plasma was resulted in the increase of the adhesion of between fibers and matrix in a composite system.

• Elastomers and Composites
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• v.45 no.1
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• pp.44-50
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• 2010

The butadiene rubber(BR) blends with chloroprene rubber(CR) were prepared by mechanical mixing method. Cure characteristics, mechanical properties, ozone resistance properties and dynamic mechanical properties were subsequently examined. The properties of ozone resistance of pure BR was significantly improved through blending with 50 wt% CR. Dynamic characteristics determined from a Rheovibron generally showed two glass transition($T_g$) for the entire blends, $tan{\delta}$ peak monotonically shifted toward the higher temperature with the increasing content of CR. Optimum cure time of compound was significantly lengthened with loading of CR.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.174-174
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• 2006

By condensing two different functional monomers, highly fluorescent aromatic polymers were prepared to produce a conjugated- conjugated spacer-type copolymer or conjugated-non-conjugated spacer-type copolymer. As synthesized polymers were soluble in an organic solvent and showed significantly enhanced optical properties compared to its monomer. Variation in the monomer composition afforded polymers having multifunctionaility such as photochromic-fluorescent polymers. Transparent thin films of the polymer as a solid medium were prepared using spin coating method and fabricated as a photoswitch, which showed photo-induced conductivity switching properties depending on the core monomeric unit in the polymers.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2315-2319
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• 2012

To improve the performance of $LiFePO_4F$, a novel sol-gel process is developed. For comparison, ceramic process is also implemented. From X-ray diffraction results we know that each sample adopts a triclinic $P{\bar{1}}$ space group, and they are isostructural with amblygonite and tavorite. The scanning electron microscope images show that the homogeneous grains with the dimension of 300-500 nm is obtained by the sol-gel process; meanwhile the sample particles obtained by ceramic process are as big as 1000-3000 nm. By galvanostatic tests and at electrochemical impedance spectroscopy method, the sample obtained by sol-gel process presents better electrochemical properties than the one obtained by ceramic process.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.651-654
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• 2014