• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.193-194
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• 2018

In this study, various materials such as epoxy material, urethane material, cement material, and acrylic material are used to solve the water leakage occurring in underground structures. However, in the reality that the durability is insufficient and the effect is insufficient, it is aimed to improve the repairing effect by using acrylics. As a second study, it is confirmed that leachate can be used as a repair material by considering long time under water stability, elongation range test, fatigue resistance test, tube stability test, damage recovery performance ana temperature stability considering leakage environment for polyacrylate. In addition, this material is applied to Expansion Joint to perform leakage repair, and to verify the effect of repairing leakage by monitoring and visual observation of concrete humidification.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.223-224
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• 2017

In this study, various materials such as epoxy material, urethane material, cement material, and acrylic material are used to solve the water leakage occurring in underground structures. However, in the reality that the durability is insufficient and the effect is insufficient, it is aimed to improve the repairing effect by using cement and acrylics in combination. As a first study, we tried to verify the performance of improve the performance by checking the product properties according to the composition ratio of polyacrylic resin. Polyacrylic resin is evaluated in three different composition ratios. When the material is selected for polyacrylic resin, it is applied to the field to understand the maintenance effect and durability.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.547-553
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• 2008

To achieve the ideal performances of paint film, resins and hardeners have to be chosen and designed in a proper way depending on the exposure circumstance of substrate and the requested physical properties. Six different kinds of clear paints were made in this experiment using alkyd polyol, polyester polyol, polyester modified acrylic polyol and another 3 acrylic polyol resins whose $T_g$ and OH value were partially modified. Then the tests for chemical, physical, and mechanical properties were measured after forming the paint films using aliphatic and aromatic polyisocyanate. The viscosity and elasticity of paint film were then measured in terms of gel point and $tan{\delta}$ using Rheometer and DMA. Through this viscoelastic characteristic test of polyurethane resin, we were able to choose the adequate resins and hardeners which are the most important in the top and primer painting system of urethane paint and, as a result of observing the physical, mechanical, and chemical properties of paint film by urethane, we have finally reached the conclusion that we could apply the proper polyol to top and primer paint for developing the polyurethane paint system.

• Journal of the Korean Ceramic Society
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• v.41 no.9
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• pp.690-695
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• 2004

In this study, inorganic (steel, asbestos and carbon) and organic (polyacryl and polyamide) fibers were used to investigate their reinforcing effects of the physical properties of Portland cement. From the load-displacement curve of each reinforced specimen, fracture strength, Young's module, fracture energy and fracture toughness were computed and compared with each other. In addition, the experiment of their impact toughness was carried out and compared with the fracture energy. For the improvement of fracture strength the inorganic (asbestos) fiber reinforcement was most effective, while the best reinforcing effect of impact toughness was achieved by organic (polyacryl) fiber. And steel fiber proved to be most adequate for improvement of both fracture strength and impact toughness. Steel fiber also showed the highest fracture energy and fracture toughness among all of the fibers.

• Polymer(Korea)
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• v.34 no.2
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• pp.150-153
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• 2010

In this research, biomolecule-immobilized multi-walled carbon nanotubes (MWCNTs) were prepared by using radiation-induced graft polymerization. For the immobilization of biomolecules, the surface of MWNCTs was functionalized by radiation-induced graft polymerization of acrylic acid. Based on the results of TGA and Raman spectroscopy it was found that acrylic acid was effectively graft-polymerized on the MWCNTs. Biomolecules such as DNA and proteins were immobilized onto the resultant poly(acrylic acid)-grafted MWCNTs. The results of the X-ray photoelectron spectroscopy and fluorescence microscopy confirmed that the biomoelcules were successfully immobilized on the poly(acrylic acid)-grafted MWCNTs.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.345-346
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• 2003

폴리아크릴로니트릴을 NaOH로 가수분해시키면 carboxylate anion과 carboxamide기가 생성되며, 물을 흡수할 경우 sodium carboxylate기의 해리로 팽윤이 크게 일어나므로 고흡수성을 지니게 된다[l]. 일반적으로 섬유가 팽윤을 하면 수축하며, 가수분해된 폴리아크릴로니트릴 섬유는 흡수되는 물 속의 염의 농도 또는 pH에 따라 팽윤도가 다르기 때문에 가수분해된 시간과 pH조건 변화에 따라서 수축하는 정도가 다르다. 과거의 연구결과에 의하면 아크릴 섬유는 2M HCI에서 최소의 길이로 수축하며, 2M NaOH에서 최대의 길이가 나타난다고 하였다[2]. (중략)

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.247-248
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• 2013

The waterproof construction for walls and floor in the underground parking lot in the construction of the apartment buildings have been excluded to the introduction of the waterproof design until now, because of the shorten construction period and the reduced construction costs. The concrete structures are existed to the joints in the vertical or horizontal parts commonly. In case of cracks, there are generated due to behavior by subsidence and external changing temperature environment. The cracks are generated by the frequent water leaks. So, the repair methods of the water leaks are proposed as the quick micro-cement and the polyacrylic resin in this study.

• Polymer(Korea)
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• v.24 no.4
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• pp.520-528
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• 2000

New high solid acrylic resins (BMHA) containing 70% of solids content have been synthesized. The environmental friendly high solid coatings (BNHS) were prepared by using these acrylic resins and polyisocyanates. The BMHA was obtained by introducing a new functional group, acetoacetoxyethyl methacrylate (AAEM), in the copolymerization of n-butyl acrylate, methyl methacrylate, and 2-hydroxyethyl acrylate. Lowering T$_{g}$ and increasing the AAEM amount in the BMHA resulted in a high value of conversion. There was no difference in conversion with the variations of OH values. In the next step, high solid BNHS coatings were prepared by the curing reaction between BMHA and polyisocyanate at room temperature. The properties of these coatings were evaluated especially for the application of automotive top-coating materials. The introduction of AAEM in the BNHS enhanced the abrasion resistance and solvent resistance of the coatings, which indicated the possible use of BNHS coatings for top-coating materials of automobile..

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.52-61
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• 2009

In this study, TAPEH (t-amyl peroxy 2-ethyl hexanoate) was selected for the reaction initiator which is a core factor for developing acrylic polyol binder. Tone M100 (caprolactone acrylate), 4HBA (4-hydroxy butyl acrylate), and 2HEMA (2-hydroxy ethyl methacrylate) were used for hydroxy-monomers. To check the applicability of raw materials mentioned above into the binders of 2 components acrylic polyurethane paint and reduce the VOC, the reactivity and film performance by different kinds of aliphatic polyisocyanate hardeners which are already generalized were reviewed. As the Tin-based catalyst has been regulated, the comparison test of reactivity and performance between the conventional catalyst and non-toxic metal catalyst recommended as the alternative was conducted as well. As a result, we were able to obtain the basic data which are necessary for applying 2 components high solid polyurethane paint and also reached a conclusion that it can be applied for developing new paints in terms of high performance, workability and environmental care.

• Polymer(Korea)
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• v.28 no.2
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• pp.143-148
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• 2004

${\alpha}$,$\omega$-Hydrogen polyorganosiloxane(HPMDMS) prepolymer was prepared from equilibrium polymerization ofoctamethylcyclotetrasiloxane, 1,3,5-trimethylcyclotrisiloxane, 1,3,5,7-tetravinyl-1,3,5,7-tetramethyl-cyclotetrasiloxane, and 1,1,3,3-tetramethyl disiloxane as an end-blocker in the presence of tetramethylammonium siloxanolate as a catalyst. Polyorganosiloxane modified with dimethylacrylamide(APMDMS) was prepared by hydrosilylation of HPMDMS with dimethylacrylamide in the presence of Pt catalyst, and followed by coordination of metal oxide (APMDMS-MO), such as NiO and FeO, to the amide moieties of the resulting polymer. The chemical structures of HPMDMS and APMDMS were confirmed by FT-IR and $^1$H-NMR analysis. Liquid silicone rubber containing metal oxide composite (LSRMO) was prepared by compounding APMDMS-MO, ${\alpha}$,$\omega$-vinylpolydimethylsiloxane, and a catalyst in a high speed dissolver. The thermal conductivity of LSRMO composite was determined to be 0.29 W/mK, and the volume resistivity exhibited a lower value than that of LSR composite. The mechanical and thermal properties of LSRMO and LSR composite were measured by UTM and TGA.