• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.104-108
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• 2011

In the non-conductive adhesives (NCAs) for adhesion of micro electro mechanical system (MEMS), there are some problems such as delamination and cracking resulting from the large differences of coefficients of thermal expansion (CTE) between NCAs and substrates. So, the addition of inorganic particles such as silica and nano clay to the CTEs composit have been applied to reduce the CTEs of the adhesives. Additions of the flexibilizers such as siloxanes have also been performed to improve the flexibility of epoxy composite. Amino modified siloxane (AMSs) were used to improve compatibility between epoxy and siloxane. In this study, glass transition temperatures (Tg) and moduli of those composites were measured to confirm the effects of AMS with two different equivalents on thermal/mechanical properties of AMS/epoxy composites. Tg of KF-8010/epoxy composites decreased from 148 to $122^{\circ}C$ and those of X-22-161A/epoxy composites decreased from 148 to $121^{\circ}C$. Moduli of KF-8010/epoxy composites decreased from 2648 to 2143 MPa by adding KF-8010 and moduli of X-22-161A/epoxy composites decreased from 2648 to 2014 MPa. In short, using long Si-O chain AMS leads to a greater decrease in moduli. However, haven't showed significant differences in Tg's.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.139-145
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• 2016

In this study, the moisture related hygroscopic characteristics and mechanical properties of epoxy-clay nanocomposites were investigated by experiments as a function of the weight fraction of nanoclay. The hygroscopic and mechanical properties including the moisture saturation amount, moisture diffusivity, adhesive strength, and tensile properties were obtained by moisture absorption test and various tensile tests, respectively. Also, the molecular dynamics (MD) simulation was devised to study of hygroscopic characteristics of nanocomposites and the results were compared to experimental results as a function of the nanoclay content. It was demonstrated that the proposed MD simulation technique can be successfully used for the prediction of the effects of the nanoclay on the moisture diffusion characteristics.

• Conservation Science in Museum
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• v.14
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• pp.29-35
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• 2013

In cases, such as white porcelain with openwork lotus scroll design, where the ceramics has intricate form and decorations, we normally use casts to restore the work, in that current restoration materials have short molding time which causes difficulties in delicate work. However, since using a cast for restoration requires longer work-time and uses more materials, we decided to restore in direct. Since the molding time in the restoration material is closely related to the workability, restoration material which secures longer work hours is necessary when directly restoring a complex form of body. Therefore we experimented on the work-time, color variation and workability as time passes by making mixtures of Epoxy putty and Baked clay in different ratios. As a result of the experiment, the mixture ratio of OS8:RQ2 turned out to be the most effective ratio.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1531-1540
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• 2002

With the invention of the inlaying technique for celadon in the latter half of the 12th century, the Koryo potters reached a new height of artistic and scientific achievement in ceramics chemical technology. Inlaid celadon shards, collected in 1991 during the surface investigation of Kangjin kilns found on the southwestern shore of South Korea, were imbedded in epoxy resin and polished for cross-section examination. Backscattered electron images were taken with an electron microprobe equipped with an energy dispersive spectrometer. The spectrometer was also used to determine the composition of micro-areas. Porcelain stone, weathered rock of quartz, mica, and feldspar composition were found to be the raw material for the body and important components in the glaze and white inlay. The close similarity between glaze and black inlay in the microstructure suggests that the glaze material was modified by adding clay with high iron content, such as biotite, for use as black inlay. The deep soft translucent quality of celadon glaze is brought about by its microstructure of bubbles, remnant and devitrified minerals, and the schlieren effect.

• Journal of Conservation Science
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• v.36 no.6
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• pp.475-482
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• 2020

In this study, we synthesized rosin-based epoxy resin and manufactured two components adhesives and epoxy putty using this epoxy resin. This study manufactured main element of adhesives for enabling it to form epoxide group by letting epichlorohydrin react to maleic anhydride modified rosin, and used room temperature curing type triethylenetetramine for hardener. The ratio between main element and hardener of of manufactured adhesives was 100 : 20, and main element and hardener of filling material were manufactured as clay type by mixing them with filler. Manufactured undiluted adhesives and filling material showed very stable result in the adhesive strength (3.06 MPa) and ultraviolet irradiation, showing outstanding result comparing to existing restoration adhesives. And it is considered a material having reversibility as it was dissolved in organic solvents such as acetone and toluene after being hardened, which showed a result that solved part of possible problems caused by restoration. As a result of use and application of manufactured adhesives and filling material for actual wood crafts, they showed excellent results in workability, stability, removability etc., and this study confirmed that the material can be used for and applied to various fields.

• Journal of Conservation Science
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• v.19
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• pp.31-42
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• 2006

There are many materials used in restoring missing parts of pottery and ceramics and they are used according to the each quality of materials. In our research we tried to find the new repair materials to solve many problems exposed in the existing repair materials. As a result, we made new repair materials that we properly put oven bake clays into repair epoxy putty which is being used as oven bake clays for a long time. Fortunately, through testing yellowing, vickers hardness, coloring and heating temperature, We could get an idea that new repair materials would be the best materials in the efficiency of restoration, yellowing, and coloring.

• Advanced Composite Materials
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• v.16 no.4
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• pp.269-282
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• 2007

Fully biodegradable high strength composites or 'advanced green composites' were fabricated using yearly renewable soy protein based resins and high strength liquid crystalline cellulose fibers. For comparison, E-glass and aramid ($Kevlar^{(R)}$) fiber reinforced composites were also prepared using the same modified soy protein resins. The modification of soy protein included forming an interpenetrating network-like (IPN-like) resin with mechanical properties comparable to commonly used epoxy resins. The IPN-like soy protein based resin was further reinforced using nano-clay and microfibrillated cellulose. Fiber/resin interfacial shear strength was characterized using microbond method. Tensile and flexural properties of the composites were characterized as per ASTM standards. A comparison of the tensile and flexural properties of the high strength composites made using the three fibers is presented. The results suggest that these green composites have excellent mechanical properties and can be considered for use in primary structural applications. Although significant additional research is needed in this area, it is clear that advanced green composites will some day replace today's advanced composites made using petroleum based fibers and resins. At the end of their life, the fully sustainable 'advanced green composites' can be easily disposed of or composted without harming the environment, in fact, helping it.

• Conservation Science in Museum
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• v.25
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• pp.9-26
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• 2021

This paper describes the production methods that were originally used for an arrow bundle excavated from a Bronze Age residential area in Auraji in Jeongseon, Gangwon-do Province and the conservation treatment process that it subsequently underwent. An arrow conventionally consists of an arrowhead and a shaft. It is rare to excavate a shaft along with an arrowhead in a complete form since the shaft is made of organic materials. Notably, the arrow bundle from the Auraji site is of great significance as it shows traces of tangless stone arrowheads attached to charred shafts and offers an important case of the split end of a piece of a tree being inserted into an arrowhead. For a further examination of the characteristics of the arrows from Auraji, microscopic investigation was conducted and the type of wood used for the arrow shafts was examined. The sequence and direction of processing and the particle sizes of the grinding tools were revealed through the analysis of traces of grinding on the stone arrowheads. The shaft is presumed to have been made from a green length of three-year-old willow (Salix spp.). A curing agent with a high degree of waterproofing and reversibility was used during the on-site curing process according to demands of the surrounding environment, and a technique that the authors call the "Bridge" method was used for emergency collection of the relics. Once the bundle was transferred to the conservation treatment lab, reinforcing materials were carefully chosen as it was important not to damage the relics during the process of turning them for the repair of their reverse sides. For this purpose, artificial clay was selected since it can safely bear a load and has excellent physical properties. Finally, detached parts were rejoined, the relics and their surrounding materials were cleaned, and the bottom sides were finished with epoxy resin prior to the display of the relics at the museum.

• Conservation Science in Museum
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• v.16
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• pp.32-45
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• 2015

The bronze incense burner, discovered in Chungung-dong, Hanam, Gyeonggi-do in 1971, is a hanging incense burner dating from the Goryeo period. The incense burner was covered with a thick layer of clay. The object was in a severely deteriorated state, affected by bronze disease which resulted in extensive corrosion. Numerous cracks were present across its surface, and some parts had been broken off. To preserve and display the bronze incense burner in a stable condition, deposits of foreign material were removed from the surface, and the weakened metal was strengthened. Cracked and broken areas were reinforced using woven glass fiber, followed by the application of epoxy resin to restore the shape. To investigate the method of production, a chemical analysis was performed, and the microstructure was examined. The chemical analysis revealed that the body of the incense burner as well as the ear, loop, lid and the knob were cast in a ternary alloy of Cu-Sn-Pb. Moreover, copper nails with high copper content were used to securely join the ear to the body of the incense burner. The microstructure was mainly α-phase, and non-intermetallic inclusions composed of Cu and S were detected.

• Journal of the Korea Furniture Society
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• v.27 no.1
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• pp.8-14
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• 2016

Increasing concerns of environment need to make change furniture field to more environmentally friendly approach, such as reuse of by-products from wooden products. As it is, the methods of recycling wood for industrial purposes have the advantage of productivity and adaptability. However, the industrial way is required a certain production facility of processing wooden by-products and has possible hygienic problems due to contaminated sources. Many designers have developed their own methods for reuse of wood in unique and artistic ways. Even so, because of confined sources, it could be not enough supply. Therefore, I developed the design methodology utilizing wooden by-products from S Design Company to relieve former ways' problems. The design suggestion took materials from a safe and abundant source. The wooden leftover pieces were connected together with epoxy clay, so previous process traces of furniture are remained as a decorative factor. Moreover, the synthesized material was able to be processed by ordinary woodworking facilities without additional installations. In doing so, console table focused on a commercial purpose and dining table for an artistic objective were successfully fabricated as final suggestions. In consideration of the proposal using wooden furniture leftovers, diverse recycling designs should be investigated for future reference.