• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.181-185
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• 2020

Hazardous and noxious substance (HNS) detection sensors were fabricated using multi-walled carbon nanotubes (MWCNTs) and various binder materials for ion batteries. To obtain uniformly printed films, the printing precision according to the substrate cleaning method was monitored, and the printing paste mixing ratio was investigated. Binders were prepared using styrene butadiene rubber + carboxymethyl cellulose (SBR+CMC), polyvinylidene fluoride + n-methyl-2-pyrrolidene (PVDF+NMP), and mixed with MWCNTs. The surface morphology of the printed films was examined using an optical microscope and a scanning electron microscope, and their electrical properties are investigated using an I-V sourcemeter. Finally, sensing properties of MWCNT printed films were measured according to changes in the concentration of the chemical under the various applied voltages. In conclusion, the MWCNT printed films made of (SBR+CMC) were found to be feasible for application to the detection of hazardous and noxious chemicals spilled in seawater.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.71-72
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• 2022

In this paper, the performance evaluation of the vibration damping ratio according to the polymer mixing ratio of the polymer modified mortar used as the floor finishing material of the apartment building structure was evaluated. To compare the vibration damping rate, ordinary potland cement (OPC) mortar and polymer modified mortar (PMM) were prepared. In addition, the mixed polymer was mixed with Styrene Butadiene Rubber (SBR) liquid polymer with a solid content of about 49%. Accordingly, the W/C of the test specimen was adjusted and compounded, and the experiment was conducted by mixing 5 types of the test specimen: OPC-60, PMM-5%, PMM-10%, PMM-15%, and PMM-20%. In addition, in order to adjust the W/C of the specimen, the fluidity of each specimen was set as 210 (±5) mm. The specimens measured density and flow in fresh mortar and after curing for 28 days, flexural strength, compressive strength and ultrasonic pulse were measured. The attenuation rate was shown. The experimental results showed that the density increased according to the mixing of the polymer, the flexural strength increased as the mixing rate of the polymer increased, and the compressive strength was decreased. In addition, it was shown that the vibration damping rate increases with the increase in the amount of polymer incorporated.

• Earthquakes and Structures
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• v.5 no.4
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• pp.477-497
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• 2013

This paper reports extensive experimental study done to compare workability and bond strength of five different types of polymer-based bonding agents for reinforcing bars in pinning retrofit. In pinning retrofit, steel pins of 6 to 10 mm diameters are inserted into holes drilled diagonally from mortar joints. This technique is superior to other techniques especially in retrofitting historic masonry constructions because it does not change the appearance of constructions. With an ordinary cement paste as bonding agent, it is very difficult to insert reinforcing bars at larger open times due to poor workability and very thin clearance available. Here, open time represents the time interval between the injection of bonding agent and the insertion of reinforcing bars. Use of polymer-cement paste (PCP), as bonding agent, is proposed in this study, with investigation on workability and bond strengths of various PCPs in brick masonry, at open times up to 10 minutes, which is unavoidable in practice. Corresponding nonlinear finite element models are developed to simulate the experimental observations. From the experimental and analytical study, the Styrene-Butadiene Rubber polymer-cement paste (SBR-PCP) with prior pretreatments of drilled holes showed strong bond with minimum strength variation at larger open times.

• Journal of the Korean Ceramic Society
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• v.50 no.2
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• pp.168-172
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• 2013

This work presents the effects of binders on the electrochemical performance of Si-C composites as the anode of lithium ion batteries. PAI (polyamide-imide) was used as an organic binder, and PAN (polyacrylonitrile), PAA (polyacrylic acid) and CMC + SBR (carboxymethyl cellulose + styrene-butadiene rubber) were used as aqueous binders. As a result, stabilization time for the cell with a Si-C composite anode synthesized using aqueous binders became shorter than an organic binder. Particularly in the case of the cell using PAA binder, better performance was observed in terms of adhesion strength, initial efficiency, the volume expansion ratio, Coulombic efficiency, and capacity retention.

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.74-81
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• 2021

Silicon (Si) is recognized as a promising anode material for high-energy-density lithium-ion batteries. However, under a condition of electrode comparable to commercial graphite anodes with low binder content and a high electrode density, the practical use of Si is limited due to the huge volume change associated with Si-Li alloying/de-alloying. Here, we report a novel core-shell composite, having a reversible capacity of ~ 500 mAh g-1, by forming a shell composed of a mixture of nano-Si, graphite nanosheets and a pitch carbon on a spherical natural graphite particle. The electrochemical measurements are performed using electrodes with 2 wt % styrene butadiene rubber (SBR) and 2 wt.% carboxymethyl cellulose (CMC) binder in an electrode density of ~ 1.6 g cm-3. The core-shell composites having the reversible capacity of 478 mAh g-1 shows the outstanding capacity retention of 99% after 100 cycles with the initial coulombic efficiency of 90%. The heterostructure of core-shell composites appears to be very effective in buffering the volume change of Si during cycling.

• Magazine of the Korea Concrete Institute
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• v.5 no.4
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• pp.145-155
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• 1993

The results of an experimental study on the manufacture and the mechanical properties of fiber reinforced fly ash$\cdot$lime$\cdot$gypsum composites are presented in this paper. 'The composites using fly ash, lime, and gypsum were prepared with various fibers (PAN-derived and Pitch-derived carbon fiber, alkali-resistance glass fiber) and a small amount of polymer emulsion-styrene butadiene rubber latex (SBR). As the test results show, the manufacturing process technology of fly ash$\cdot$lime$\cdot$gypsum composites was developed and its optimum mix proportions were successfully proposed. And the flexural strength and toughness of fiber reinforced fly ash$\cdot$lime $\cdot$gypsum composites were increased remarkably by fiber contents, but the compressive strength of the composites were influenced by the kinds fiber more than by the fiber contents. Also, the addition of a polymer emulsion to the composites decreased the bulk specific gravity, but the compressive and flexural strength, and the toughness of the composites were not influenced by it, but were considerably improved by increasing fiber contents.