• Fire Science and Engineering
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• v.30 no.1
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• pp.31-36
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• 2016

This study investigates the characteristics of thermal decomposition of an epoxy-based intumescent paint using thermogravimetric analysis (TGA) and numerical simulation. A mathematical and numerical model is introduced to describe mass loss profiles of the epoxy-based intumescent coating induced by the thermal decomposition process. The decomposition scheme covers a range of complexity by employing simplified 4-step sequential reactions to describe the simultaneous thermal decomposition processes. The reaction rates are expressed by the Arrhenius law, and reaction parameters are optimized to fit the degradation behavior seen during thermogravimetric (TG) experiments. The experimental results show a major 2-step degradation under nitrogen and a 3-step degradation in an air environment. The experiment also shows that oxygen takes part in the stabilization of the intumescent coating between 200 and $500^{\circ}C$. The simulation results show that the proposed model effectively predicts the experimental mass loss as a function of time except for temperatures above $800^{\circ}C$, which were intentionally not included in the model. The maximum error in the simulation was less than 3%.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1014-1020
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• 2004

In this study, durability of the nano-level inorganic polymer based coatings which can provide a barrier against the ingress of moisture or aggressive ions to concrete is discussed. For the durability evaluation of the coatings, chloride penetration test, accelerating carbonation test, freezing and thawing test, and sulfate ponding test are conducted. As the result of this study, concrete applied nano-level inorganic polymer based coatings has a much higher resistance to the ingress of chloride ion, carbon dioxide, moisture and aggressive acid than plain concrete and epoxy resin based paint by means of crosslinking three-dimensional structure with concrete structure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.90-91
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• 2017

Concrete can be used semi-permanently unless the steel is corroded. However, the concrete exposed to the marine environment is exposed to sea breeze, so chloride ions penetrate into the concrete and the steel is corroded accordingly. In order to solve these problems, there is a method of increasing the covering depth of the concrete and an application of the epoxy paint to the steel. In this study, the hydrotalcite type corrosion inhibitor was mixed with the concrete and the compressive strength, chloride diffusion coefficient and the corrosion properties of the steel were examined.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.573-581
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• 2021

In this study, a basic experiment was conducted to examine the possibility of using mechanochromic sensors to monitor the health of construction structures. The strain and color variation characteristics of the mechanochromic sensor according to the type of finish of the concrete material were investigated. As a result, it was confirmed that the strain and color variation reactivity of the mechanochromic sensor increased as the tensile strain of the concrete specimen increased. In addition, the difference in the finishing environments of concrete, urethane, epoxy, water-based paint and oil-based paint did not affect the deformation and discoloration characteristics of the mechanochromic sensor.

• Conservation Science in Museum
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• v.16
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• pp.114-121
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• 2015

Two pieces of comb-shaped jewelry which are made of animal bones were discovered in Daeseong-dong tomb No.88 in Gimhae. Foreign material was removed from the surface of the objects using ethanol and various small instruments. Fractures or cracks were repaired using cellulose-type synthetic resin and epoxy resin. Acrylic paint was applied repaired areas to match the color and finished conservation treatment. The two comb-shaped accessories, although differing in number of teeth and thickness, were produced by using the same method. A series of fine bone pieces, shaped like comb teeth, are placed between two long bones, assuming animal ulnas, and are fastened together by tying silk thread around them several times, then by placing a coat of lacquer.

• Conservation Science in Museum
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• v.12
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• pp.71-76
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• 2011

This study examined characteristics and structure of earthen Janggu that were excavated from Jeollabuk-do and other regions, and it described conservation process of earthen Janggu that were excavated from Samsanyujeok Jeonju. Earthen Janggu that were excavated from Samsanyujeok were destroyed and lost by more than one third, and they were thought to make use of them at living lives. We take an x-ray of center of the Janggu for inspect production technique and, destroyed area of the Janggu was recovered by making recovery frame made by plaster and using epoxy series CDK-520. After recovery, acrylic paint was used to do color matching and to get rid of sense of difference of the area that was recovered and remained.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.133-136
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• 2005

The accidents attributed to the forklift have increased as the number of the forklift increases. It is significant that most of the accidents were fatal. This study investigated slip distance of forklift depending upon the floor materials and their conditions in industrial site. For doing this, an experiment was conducted, in which the floor materials and their conditions were adopted as independent variables and the slip distance as dependent variable. Six floor materials included asphalt concrete, two color hardener mortar, epoxy paint and deluxe tile. Two types of floor conditions, wet and dry, were used in the experiment. The results showed that the slip distance was shorter on the asphalt and concrete floors than on other floors, and that the distance on the wet floor was six times longer than that on the dry condition. Based on this result, it is recommended that as in the advanced countries, the regulation or standard on the floor conditions such as friction coefficient be established for reducing forklift relevant accidents.

• Journal of ILASS-Korea
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• v.13 no.1
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• pp.42-50
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• 2008

In the present work, atomization characteristics of shear-thinning liquid slurry discharging from fan spray nozzles were studied experimentally for spray painting applications. The effects of solid particle size and concentration on the properties (especially on the viscosity) of suspensions and mean drop size were examined by using model fluids. In the range of low particle concentration (below 3 wt%), the fluid viscosity was primarily determined by the particle size. On the other hand, in the range of high particle concentration (higher than 10 wt%), the agglomeration phenomenon and the oil absorption capability of solid particles played major roles in determining the fluid viscosity. In the high concentration region, which most of the paints belong to, the fluid became more viscous and the shear thinning behavior appeared more prominent as the particle concentration was increased. In this region, mean drop size(SMD) decreased more rapidly with the increase of the injection pressure. Also, SMD became larger with the higher particle concentration and the larger particle size.

• Journal of Conservation Science
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• v.27 no.1
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• pp.115-121
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• 2011

A Urethane resin restoration material was made to be used in the restoration of stone cultural assets. The Urethane resin restoration material showed strong adhesive strength and tensile strength similar to epoxy recovery material, which had been mainly used for the recovery of stone cultural assets. The sealing property, anti-shrinking property and paint-ability of Urethane resin restoration material are also similar to existing epoxy system restoration materials. Especially, this Urethane resin restration material is expected to give permanence and continuous stability in the restoration of cultural assets made in stone by resolving the two big issues of existing epoxy recovery material, which are 'yellowing' and 'ir-reversibility'. This Urethane resin restration material had been directly applied as a filling material and adhesive and it was dissolved again. The Urethane resin, which had been used for the recovery, was able to be perfectly removed, which means that this Urethane resin recovery material has perfect reversibility. This Urethane resin restoration material also has enhanced convenience since user can adjust the working-life dependent on work environment. It is believed that this Urethane resin restoration material can also be used as a filling material or adhesive for other cultural assets made of ceramic or metal heritage, in addition to stone, since it has strong adhesive strength and tensile strength.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.5-14
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• 2023

In this study, LiDAR-reflective black hollow-structured silica/titania(B-HST) materials are successfully synthesized by employing the NaBH₄ reduction and etching method on silica/titania core/shell(STCS) materials, which also effectively enhance near-infrared(NIR) reflectance. Moreover, core-etched supernatant solutions are collected and recycled for the synthesis of extracted silica(e-SiO₂) process, which successfully applies as filler materials for semiconductor epoxy molding compound(EMC). In detail, B-HST materials, fabricated by the sequential experimental steps of sol-gel, reduction, and sonication-mediated etching method, manifest blackness(L^*) of 13.2 similar to black paint and excellent NIR reflectance(31.1%). Consequently, B-HST materials are successfully prepared as LiDAR-reflective black materials. Additionally, core-etched supernatant solution with silanol precursors are employed for synthesis of homogeneous silica filler materials via sol-gel method. As-synthesized silica fillers are incorporated with epoxy resin and carbon black for the preparation of semiconductor EMC. Experimentally synthesized EMC exhibits comparable mechanical-chemical properties to commercial EMC. Conclusively, this study successfully proposes designing procedure and practical experimental method for simultaneously synthesizing the NIR-reflective black materials for self-driving vehicles and EMC materials for semiconductors, which are materials suitable for the industrial 4.0 era, and presented their applicability in future industries.