• 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.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.11a
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• pp.54-55
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• 2001

• Journal of Powder Materials
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• v.27 no.1
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• pp.63-71
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• 2020

It is necessary to fabricate uniformly dispersed nanoscale catalyst materials with high activity and long-term stability for polymer electrolyte membrane fuel cells with excellent electrochemical characteristics of the oxygen reduction reaction and hydrogen oxidation reaction. Platinum is known as the best noble metal catalyst for polymer electrolyte membrane fuel cells because of its excellent catalytic activity. However, given that Pt is expensive, considerable efforts have been made to reduce the amount of Pt loading for both anode and cathode catalysts. Meanwhile, the atomic layer deposition (ALD) method shows excellent uniformity and precise particle size controllability over the three-dimensional structure. The research progress on noble metal ALD, such as Pt, Ru, Pd, and various metal alloys, is presented in this review. ALD technology enables the development of polymer electrolyte membrane fuel cells with excellent reactivity and durability.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.82-89
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• 2016

In this paper, various of experiments were performed for checking the usefulness of Pozzolan Inorganic Polymer(PIP) Waterproof Admixture. The results of the experiment enabled to set the optimum mixture ratio of PIP waterproof admixture as 3.5%. Then, the test specimen mixed with PIP waterproof admixture was produced and consider whether meeting the quality standard of waterproofing admixture for concrete (KS F 4926) From the results, all the items such as mechanical properties and durability were meet the quality standard of KS. The PIP waterproof admixture concrete shows the high resistance of absorption, permeability and chloride ion penetration thanks to its internal components such as siliceous powder, zinc stearate and dispersive polymer.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.559-562
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• 2005

The purpose of this study is to evaluate the durability and bond strength of polymer powder-modified mortars with special accelerator components. The mortars were prepared with various polymer-binder ratios and applied to the concrete substrate as a repair material. Bond strength, flexural and compressive strengths, freeze-thaw resistance and carbonation resistance were measured for the test. As a result, bond strength of the mortars was increased with an increase in the polymer-cement ratio, and freeze-thaw resistance and carbonation resistance were significantly improved with increasing polymer-cement ratio also.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.537-540
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• 2005

Durability of the polymer-modified mortars using the redispersible SBR and PAE powder-modified mortars were experimentally investigated. Results of a previous study were used to determine the mix proportion that optimized the strength, and the freezing-thawing resistence, the carbonation depth and the chloride intrusion depth of the mortar for various polymer-cement ratios were studied. After 300 freezing-thawing cycles, the rate of weight reduction decreased from 7 to below 2 $\%$ as the polymer-cement ratios increased from 0 to 15 $\%$, and, on the 150 cycle basis, durability index increased from 60 to 98. Carbonation depth decreased from initial value of 5.5 to about 2.5 mm and chloride intrusion depth did from 3.5 to 1.5 mm

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.257-260
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• 2005

Graphite reinforced conductive polymer composites were fabricated by the compression molding technique. Graphite powder was mixed with an phenol resin to impart electrical property in composites. The ratio and particle size of graphite powder were varied to investigate electrical conductivity of cured composites. In this study, graphite reinforced conductive polymer composites with high filler loadings(>66wt.%) were manufactured to accomplish high electrical conductivity. With increasing the loading ratio of graphite powder, the electrical conductivity and flexural strength increased. However. above 80wt.% filler loadings, flexural strength decreased due to lack of resin. Regardless of graphite particle size, electrical conductivity wasn’t varied. On the other hand, with decreasing particle size, flexural strength increased due to high specific surface area.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1360-1363
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• 2007

The bus electrode is composed of two layers. One is the black matrix(BM) and silver layer is formed on top of black layer. The BM paste is made by mixing $Co_3O_4$ black powder with photosensitive vehicle and rheological additives. In this work we studied the effect of $Co_3O_4$ black powder and glass frit on the rheological property of photosensitive BM paste. We also examined how the size and content of black powder and glass frit affect the transmittance and reflectance of the BM layer after sintering.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1989.06a
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• pp.77-80
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• 1989

The aim of the study is to develope the processing technique of PZT-Polymer piezoelectric composite materials for ultrasonic transducer application such as biomedical probe and hydrophone. Piezoelectric composite of PZT and polymer with 1-3 connectivity patterns have been fabricated by dicing-filling method and extrusion forming method. In this study processing forming method. In the study processing steps by extrusion forming method in the preperation of PZT/polymer piezoelectric composites are described. The PZT powder used in the study is commercial powder which is prepared by mixing PbO, TiO$_2$ and ZrO$_2$. The binder, water and plasticizer are mixed with the PZT powder to form a slip. It is necessary to adjust the viescosity of slip according on the PZT rod diameters to be extruded. The electromechanical properties of the piezoelectric composites are characterized in terms of the thickness resonance mode. The pulse response characteristics by the ultrasonic transducer analyzer and osciloscope are evaluated.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.159-166
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• 2012

We have introduced the Pickering emulsion systems to generate novel confining geometries for the selforganization of monodisperse polymer microspheres using nanoparticle-stabilized emulsion droplets encapsulating the building block particles. Then, through the slow evaporation of emulsion phases by heating, these microspheres were packed into regular polyhedral colloidal clusters covered with nanoparticle-stabilizers made of silica. Furthermore, polymer composite colloidal clusters were burnt out leaving nonspherical hollow micro-particles, in which the configurations of the cluster structure were preserved during calcination. The selfassembled porous architectures in this study will be potentially useful in various applications such as novel building block particles or supporting materials for catalysis or gas adsorption.