• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.103-104
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• 2015

This study is an experiment about what affects the compressive strength by using a reducing agent (PNS based admixtures) to play cement using the cement paste based Waste Concrete Powder of waste concrete, which accounts for more than 60% of construction waste around the latest domestic and international It was. Securing the replacement of cement with Waste Concrete Powder and, by varying the admixture was to compensate for the low absorption of liquidity and obtain a fine powder. And the experiment was conducted with a constant water cement ratio and aggregate usage for the purpose of lowering the water cement ratio promoting strength development. When substituted with the experimental results of 0.3% based on 3 ~ 28 days as strength 36Mpa exhibited the highest strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.673-676
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• 2006

Steel FibreReinforced Shotcrete(SFRS) is one of the main tunnel support along with the rock bolt during the excavation and after the completion of the tunnel. In the standard qualification of the SFRS defined by Korea Highway Corporation, 28 day core specimen has to meet the compressive strength of 19.6 MPa and over 90 % fibre contents. Furthermore, for the 28 days brick shaped specimen made by shooting, flexural strength should be over 4.4 MPa and flexural toughness ratio which can be calculated from flexural toughness factor has to meet more than 68% of flexural strength. In shotcrete, accelerating agent is added for the rapid strength development. Silicate and aluminate type agents are known to develop shotcrete strength rapidly, however, has such problem to degrade the middle and long term strength. Hence, using poly carboxylic super plasticizer, it was aimed to enhance the quality of the shotcrete with the lower water-cement ratio and the same level of workability. The present paper shows the part of the field test result and its analysis.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.42-47
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• 2019

The four different polymer compounds were manufactured to make cable sheath for ship industry. Two kinds of ethylene-vinyl acetate (EVA) were selected as main matrix polymers for compounding with fire retardant, crosslinking agent, filler, plasticizer, and other additives. The properties of the four compounded materials were investigated with the contents of fire retardant, silane coated aluminum hydroxide (S-ATH). Rheology, Mooney viscosity, and tensile strength increased with S-ATH contents by reinforcing effect. With increasing fire retardant amount, fire resistance increased, but cold resistance didn't show an obvious enhancement due to polar effect of vinyl acetate in EVA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.727-731
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• 2009

Effects of various plasticizers (1.5%) such as glycerol, sorbitol, fructose, sucrose, and polypropylene glycol, and ferulic acid on the physical properties of Gelidium corneum (GC) film were examined. GC films containing plasticizer and ferulic acid were prepared by incorporating various amounts (10, 30, 50, 70, 100 mg/100 mL) of ferulic acid into the film. Water vapor permeability (WVP) of the GC film varied depending on the type of plasticizer, and among them the film containing sucrose had the lowest WVP. Tensile strength (TS) and % elongation (%E) of the film were in the range of $1.29{\sim}11.29$ MPa and $5.55{\sim}36.44$ %, respectively, and the WVP values were of $1.30{\sim}1.60\;ng\;m/m^{2}sPa$. In addition, the GC films were prepared using ferulic acid as a cross-linking agent. WVP of the film decreased with the addition of ferulic acid, and the film containing 30 mg ferulic acid had the lowest WVP value. TS value of the GC film containing 10 mg of ferulic acid was significantly higher than that of the control. However, further increase of ferulic acid concentration decreased the TS value. Therefore, 10 mg of ferulic acid was determined to be the optimal concentration for the film.

• Analytical Science and Technology
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• v.20 no.6
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• pp.488-495
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• 2007

A wallpaper having many surfaces in indoor is composed of various raw materials. In this study, TVOC contribution from raw materials of PVC wallpaper was evaluated by using headspace-solid phase microextraction (HS-SPME)-GC/MS. Samples were diluent, resin stabilizer, plasticizer, filler, blowing agent and PVC resin. 9 mL of each sample was put into 22 mL glass vial and they were equilibrated for 1 hour at $100^{\circ}C$. Headspace in vial was absorbed to $75{\mu}m$ Carboxen-PDMS fiber and analyzed by GC/MS. Aromatic compounds like a toluene, ethylbenzene and xylene, ketones compounds like a acetone, methoxyacetone and 2-butanone and alkane compounds like a nonane decane and undecane were identified from raw materials. And alcohol compounds like a ethanol and butanol and aldehydes were detected. TVOC emission of diluent, resin stabilizer, plasticizer, PVC resin, blowing agent and filler were $54.20{\mu}g/g$, $32.88{\mu}g/g$, $0.50{\mu}g/g$, $0.88{\mu}g/g$, $0.22{\mu}g/g$ and $0.11{\mu}g/g$, respectively. Contribution of TVOC emission of diluent, resin stabilizer and PVC resin that were concerned about add ratio were 0.708, 0.129, 0.115, respectively. In conclusion, it's necessary to reduce TVOC emission through improvement of diluent, resin stabilizer and PVC resin. Also, HS-SPME-GC/MS method which was developed in this study will be used for raw materials analysis effectively.

• Polymer(Korea)
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• v.35 no.5
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• pp.488-492
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• 2011

Three isocyanatopropyldimethoxysilylpolydimethylsiloxanes(IDMSi-PDMS) were synthesised from the reaction of isocyanatopropyltrimethoxysilane with monohydroxyl group termainated PDMS having different molecular weight($M_n$=5000, 10000, and 20000). Then PDMS modified polyurethane hybrid elastomer(PSMPH) were prepared from the reaction of IDMSi-PDMS with ${\alpha}$, ${\omega}$-hydroxyl group terminated polyurethane. PSMPH sealant was prepared by compounding PSMPH elastomer with additives such as plasticizer, adhesion promoter, crosslinking agent, vicosity increasing agent, inorganic filler, and catalyst at room temperature under nitrogen atmosphere. The methoxy group in the PSMPH sealant should be crosslinked with the hydroxyl group in the building stone or moisture by typical sol-gel reaction. The adhesive strength of the sealant having PDMS of $M_n$=5000 showed 40.28 kg of maxium load and 20.14 kg of break load. The shrinkage rate of the sealant having PDMS of $M_n$=20000 was 5.7% as the best result. Also, their skin over time, slump, oil content after 8 days under oil soaked paper and alkaline resistance characteristics show good results.

• Elastomers and Composites
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• v.35 no.4
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• pp.303-310
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• 2000

Low temperature retraction characteristics were investigated on the cured natural rubber with various ratios of crosslinking agents, filler and additives. The cured natural rubber product was elongated about 200% at $-40^{\circ}C$ for 24 hours and then retracted. In a definite range, the retraction was increased as the sulfur to accelerator ratio increased and as the filler contents decreased. The retraction was maximum for a definite range of amount of accelerators, plasticizer and activator. Adding some peroxide additively retraction characteristics improved and curing time got longer.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.240-248
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• 2011

All-vanadium redox flow battery (VRFB) has been studied actively as one of the most promising electrochemical energy storage systems for a wide range of applications such as electric vehicles, photovoltaic arrays, and excess power generated by electric power plants at night time. Among consisting elements of the VRFB, the ion exchange membrane and the electrode play important roles. In this study, carbon PVC coposite sheets for the VRFB have been developed and electrochemical characteristics investigated. Current collector for VRFB, carbon PVC composite sheets (CPCS), were prepared with G-1028 as a conducting particle, PVC as a polymer, Dibutyl phthalate (DBP) as a plasticizer and fumed Silica (FS) as a dispersion agent. CPCS has been shown to have the characteristics as an excellent current collector for VRFB and electrochemical properties of specific resistivity 0.31 ${\Omega}cm$, which were composed of G-1028 80 wt%, PVC 10 wt%, DBP 5 wt% and FS 5 wt%.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.154-158
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• 2001

The heat treatment of PVC film containing PVC 65%, DOP(Dioctyl Phthalate) 32% as plasticizer, Ca-Zn stearates and surface agent was peformed under several conditions to study the degradation behavior of PVC sheet. In the case of H$_2$SO$_4$, the dehydrochlorination was ca.100% at 25$0^{\circ}C$ for 3h. The char involving the smaller pores was produced with hydrothermal treatment. The pore size became small with increasing the treatment time and temperature. In the case of treatment with Ca(OH)$_2$, the sizes of pores produced in char were about sever ~ 10${\mu}{\textrm}{m}$ at 2$25^{\circ}C$ for 12h. In the case of H$_2$SO$_4$, the size of pores were about 1${\mu}{\textrm}{m}$ in 5M H$_2$SO$_4$for 12h.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.746-750
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• 2001

The heat treatment of PVC film containing PVC 65%, DOP(Dioctyl Phthalate) 32% as plasticizer, Ca-Zn stearates and surface agent was peformed under several conditions to study the degradation behavior of PVC sheet. In the case of H$_2$SO$_4$, the dehydrochlorination was ca.100% at 25$0^{\circ}C$ for 3h. The char involving the smaller pores was produced with hydrothermal treatment. The pore size became small with increasing the treatment time and temperature. In the case of treatment with Ca(OH)$_2$, the sizes of pores produced in char were about sever ~ 10${\mu}{\textrm}{m}$ at 2$25^{\circ}C$ for 12h. In the case of H$_2$SO$_4$, the size of pores were about l${\mu}{\textrm}{m}$ in 5M H$_2$SO$_4$for 12h.