• Elastomers and Composites
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• v.39 no.3
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• pp.217-227
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• 2004

A new thermotropic liquid crystalline polymer(TLCP) containing a triad aromatic ester type mesogenic unit and butylene terephthalate unit(BT) in the main chain was synthesized by polycondensation reaction. The TLCP synthesized showed nematic mesophasic behavior and its transition temperature from solid to mesophase was $260^{\circ}C$. The TLCP/PBT blends were prepared by in-situ polymerization in PBT solution and characterized by differential scanning calorimeter(DSC), thermogavimetric analyzer(TGA), scanning electron microscope(SEM), x-ray diffractometer(XRD), and dynamic mechanical thermal analyze, (DMTA). The blends showed well dispersed TLCP phases with domain sizes $0.05{\sim}0.2{\mu}m$ in the PBT matrix. As the increasing TLCP content from 5 to 20 wt%, ${\Delta}Hm$ values of pure PBT in the blend were increased because TLCP acts as a nucleating agent in the PBT matrix. The mechanical properties of the blends depended on the TLCP contents because the TLCP acted effectively as a reinforcing material in the PBT matrix. The blends showed good interfacial adhesion between the TLCP phase and PBT matrix.The blends prepared by in-situ polymerization showed higher mechanical properties and well dispersed TLCP domains than those of the blends prepared by melt blending.

• Polymer(Korea)
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• v.34 no.4
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• pp.300-305
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• 2010

Zaltoprofen is a propionic acid derivative of non-steroidal anti-inflammatory drugs (NSAIDs) and has been widely used in the treatment of a number of arthritic conditions or lumbago. Zaltoprofen has low water solubility and low bioavailability, therefore great efforts have been devoted to enhance the extent of drug adsorption. In this study, zaltoprofen was formulated into a tablet to enhance the bioavailability and to achieve sustained-release using additives such as lactose monohydrate, carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC). Fourier transform-infrared (FTIR) and differential scanning calorimeter (DSC) were employed to study the structure and crystallization of zaltoprofen in the tablet with various contents of additives. It was found that additives had interactions with zaltoprofen and inhibited the crystallization of zaltoprofen. Tablets containing low viscosity HPMC showed a higher release than those containing high viscosity HPMC. Also, as the amount of CMC increased zaltoprofen release increased.

• Polymer(Korea)
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• v.34 no.4
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• pp.333-340
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• 2010

Zaltoprofen, a propionic acid derivative non-steroidal anti-inflammatory drug (NSAID), is known to have powerful inhibitory effects on acute, subacute and chronic inflammation. We developed poly(lactide-co-glycolide)(PLGA) microspheres loaded with zaltoprofen for sustained controlled delivery using an oil-water solvent evaporation methods by varying PLGA molecular weight and cosurfactant contents. Physicochemical properties and morphology of zaltoprofen-loaded PLGA microspheres were investigated by scanning electron microscope, X-ray diffraction and differential scanning calorimeter. The size of microspheres increased with the molecular weight of PLGA and the content of cosurfactants. The increase of PLGA molecular weight and cosurfactant content decreased the porosity of microspheres, subsequently resulting in the slow drug release. The results demonstrated that the adjustment of PLGA molecular weight and the cosurfactant content allowed us to control the drug release profiles of drug-loaded microspheres.

• Applied Chemistry for Engineering
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• v.32 no.2
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• pp.197-204
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• 2021

This study investigated the smoke risk assessment of woods and plastics for construction materials, focusing on the smoke performance index-V (SPI-V), smoke growth index-V (SGI-V), and smoke risk index-VI (SRI-VI) according to a newly designed methodology. Spruce, Lauan, polymethylmethacrylate (PMMA), and polycarbonate (PC) were used for test pieces. Smoke characteristics of the materials were measured using a cone calorimeter (ISO 5660-1) equipment. The smoke performance index-V calculated after the combustion reaction was found to be 1.0 to 3.4 based on PMMA. Smoke risk by smoke performance index-V was increased in the order of PC, Spruce, Lauan and PMMA. Lauan and PMMA showed similar values. The smoke growth index-V was found to be 1.0 to 9.2 based on PMMA. Smoke risk by smoke growth index-V increased in the order of PMMA, PC, Spruce, and Lauan. COpeak production rates of all specimens were measured between 0.0021 to 0.0067 g/s. In conclusion, materials with a low smoke performance index-V and a high smoke growth index-V cause a high smoke risk from fire. Therefore, it is understood that the smoke risk from fire is high. It is collectively summarized by the smoke risk index-VI.

• Food Engineering Progress
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• v.14 no.2
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• pp.135-145
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• 2010

In order to enhance overall quality of the Backsulki, a sweet potato flour (SPF) which is rich in sugar and dietary fiber was added into the rice flour at 0, 5, 15, and 25% (w/w, db) ratios. Quality changes of the products were evaluated by storing at 5, 15, and 25$^{\circ}C$ for 4 days. Water binding capacity, swelling power, and solubility of the products increased as the SPF increased. Hunter colorimetric a- and b-value increased while L value of the products decreased as the SPF increased. Retarded retrogradation of the flour mixtures containing the SPF was shown from the DSC thermogram as indicated by the decreased $\Delta$H values. Increases in $T_{i}$ and $T_{p}$ values in relation with the starch gelatinization were shown from the DSC thermogram with a temperature margin of 15-20$^{\circ}C$ as the SPF increased. Increases in softness along with decreases in springiness and chewiness of the products were shown as the SPF increased. It was not so much the storage temperature as the added SPF affected the final texture of the products. Retarded growth of the total microbes of the products was noted by the added SPF during storage at 25$^{\circ}C$ for 3 days. Regarding the above and additional sensory preference scores of the products, a 15%(w/w) level of the SPF was suggested as optimum for the best Backsulki with improved qualities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.443-450
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• 2019

We studied to find the optimal manufacturing conditions of coffee grounds sludge RDF with oil drying method. We expanded the lab scale to pilot scale to compare the efficiency of the oil-drying equipment and The selection of the ratio of coffee grounds and oil, the setting temperature, and the temperature change and water content with time were measured. In order to analyze the characteristics of the research results, characteristics of solid fuels produced(Coffee grounds of oil-dried) by calorimeter, TGA, combustion equipment, and combustion gas measuring instrument were analyzed. As a result, the ratio of oil to coffee grounds was 4: 1, and when the setting temperature was set to $300^{\circ}C$, the water content reached 10wt.% or less within 20 minutes. ln addition, it showed high calorific value of 6,273kcal/kg. However, coffee grounds had a similar composition to wood and showed high luminance and produced a lot of CO in combustion gas. As a result, it is considered to be unsuitable for thermoelectric power plant and camping fuel, but the initial ignition speed is high and the heat generation is high, so it is considered that it can replace the fuels for current use.

• Fire Science and Engineering
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• v.33 no.2
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• pp.9-19
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• 2019

Experiments on the combustion characteristics of untreated wood specimens and those treated with four types of silicone compounds were carried out using a cone calorimeter according to the ISO 5660-1 standard. 3-Aminopropyltrimethoxysilane (APTMS), 3-(2-aminoethylamino) propylmethyldimethoxysilane (AEAPMDMS), and 3-(2-aminoethylamino) propyltrimethoxysilane (AEAPTMS) were used as the silane compounds. The flame retardants were synthesized with sodium silicate and amino silane compounds. The measured time to ignition after combustion at an external heat flux of $50kW/m^2$ was 9 s to 11 s. Time to ignition was marked with a delayed value in the 3 s to 5 s range. The peak heat release rate ($HRR_{peak}$) was reduced by 5 to 20% compared with the uncoated specimen, and AEAPMDMS showed the highest initial fire risk. The total heat release (THR) was decreased by 1 to 22%. Compared to the untreated specimen, the fire performance index (FPI) of the specimens coated with silicone sol compounds increased by 1.5 to 2.2 fold. The fire growth index (FGI) of the AEAPMDMS specimen was increased by 30% and the others were decreased by 93 to 94%. Therefore, the fire risk of wood coated with silicone compounds was improved in terms of the heat risk properties.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.670-676
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• 2018

Experiments on combustion gases generation of untreated cypress specimens or treated with boric acid, ammonium pentaborate, and boric acid/ammonium pentaborate additive were carried out. Test specimens were painted three times with 15 wt% boron compound aqueous solutions. After drying, the generation of combustion gas was analyzed using a cone calorimeter (ISO 5660-1). As a result, comparing to untreated specimen, the smoke performance index (SPI) of the specimens treated with the boron compound increased by 1.37 to 2.68 times and the smoke growth index (SGI) decreased by 29.4 to 52.9%. The smoke intensity (SI) of the specimens treated with boron compounds is expected to be 1.16 to 3.92 times lower than that of untreated specimens, resulting in lower smoke and fire hazards. Also, the maximum carbon monoxide ($CO_{peak}$) concentration of specimens treated with boron compounds was 12.7 to 30.9% lower than that of untreated specimens. However, it was measured to produce fatal toxicities from 1.52 to 1.92 times higher than that of permissible exposure limits (PEL) by Occupational Safety and Health Administration (OSHA). The boron compounds played a role in reducing carbon monoxide, but it did not meet the expectation of reduction effect because of the high concentration of carbon monoxide in cypress itself.

• Fire Science and Engineering
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• v.33 no.1
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• pp.76-84
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• 2019

Experimental studies using an open cone calorimeter were conducted to provide information on the CO and soot yields of wood combustibles required for a kitchen fire simulation of PBD. A total of eight specimens were examined for medium density fiberboard (MDF) and particle board (PB), which are used widely in kitchen furniture production, depending on the water content, surface processing method, and surface color. The thermal penetration time related to the fire spread rate in the depth direction differed significantly according to the surface processing treatment method, even for a specimen of identical thickness. The CO yield ($y_{CO}$) of the MDF and PB series did not change significantly according to the combustion mode and surface treatment process in flaming mode. On the other hand, $y_{CO}$ was approximately 10 times higher in smoldering mode than in flaming mode. The soot yield ($y_{soot}$), however, varied considerably depending on the combustion mode and surface treatment process. In particular, a higher $y_{soot}$ was found in flaming mode and in the surface-treated specimens. Finally, the $y_{CO}$ and $y_{soot}$ of MDF and PB measured for the kitchen fire simulation of PBD were applied.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.330-337
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• 2021

3D printing is not only at the fundamental study and small-scale level, but has recently been producing buildings that can be inhabited by people. Buildings require a lot of cost and labor to work on the form work, but if 3D printing is applied to the building, the construction industry is received attention from technologies using 3D printing as it can reduce the construction period and cost. 3D printing technology for buildings can be divided into structural and non-structural materials, of which 3D printing is applied to non-structural materials. Because 3D printing needs to be additive manufacturing, control such as curing speed and workability is needed. Since cement mortar has a large shrinkage due to evaporation of water, cement polymer dispersion is used to improve the hardening speed, workability, and adhesion strength. The addition of polymer dispersion to cement mortar improves the tensile strength and brittleness between the cement hydrate and the polymer film. Cement mortar using polymer materials can be additive manufacturing but it has limited height that can be additive manufacturing due to its high density. When light-weight materials are mixed with polymer cement mortar, the density of polymer cement mortar is lowered and the height of additive manufacturing, so it is essential to use light-weight materials. However, the use of EVA redispersible polymer powder and light-weight materials, additional damage such as cracks in cement mortar can occur at high temperatures such as fires. This study produced a test specimen incorporating light-weight materials and EVA redispersible polymer powder to produce exterior building materials using 3D printing, and examined flame resistance performance through water absorption rate, length change rate, and cone calorimeter test and non-flammable test. From the test result, the test specimen using silica sand and light-weight aggregate showed good flame resistance performance, and if the EVA redispersible polymer powder is applied below 5%, it shows good flame resistance performance.