• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.185-186
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• 2005

저온소결 Glass/Ceramic계 기판재료 조성으로 $Al_2O_3$, $SiO_2$, Cordierite, $Al_2O_3{\cdot}3SiO_2$의 4가지 filler에 zinc-borosilicate(ZBS) glass를 첨가하여 기판재료로의 사용가능성을 조사하였다. 4가지 filer에 ZBS glass를 30$\sim$50vol%첨가하여 $700\sim950^{\circ}C$에서 2시간 소결한 결과 40, 50vol%첨가 했을 때 900$^{\circ}C$에서 치밀한 소결체를 얻을 수 있었다. LSI칩 신호라인의 빠른 신호전달에 직접적인 영향을 주는 유전율은 기존의 $Al_2O_3$기관($\fallingdotseq$9.7)보다 저유전율 ($900^{\circ}C$에서 $Al_2O_3$-50vol%ZBS 5.7, $SiO_2$-50vol%ZBS 5.9, Cordierite-40vo1%ZBS 5.9, $Al_2O_3${\cdot}3SiO_2$-50vol%ZBS 4.9)을 나타내어 저온소결 기판재료로 사용이 가능함을 확인하였다.

• Elastomers and Composites
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• v.41 no.1
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• pp.19-26
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• 2006

In this study, the effect of thermal aging temperature on the weight loss, glass transition temperature, and morphology of epoxy adhesives cured with amine (D-230), amide (G-5022), and anhydride (HN-2200) was investigated. As a result, the weight loss of three specimens was increased with increasing the thermal aging temperature. The result was attributed to the thermal aging which was occurred at the surface of adhesive specimens at high aging temperature, resulting in increasing the weight loss of the specimens. According to the DSC result, the glass transition temperature of DGEBA/D-230 and DGEBA/G-5022 samples war increased as the aging temperature increased, whereas the glass transition temperature of DGEBA/HN-2200 samples was constant above aging temperature of $150^{\circ}C$ and aging tine of 7 days. The SEM result indicated that the surface of DGEBA/G-5022 specimen showed more rough topography than that of DGEBA/D-230 or DGEBA/HN-2200 specimen after thermal aging. This could be correlated with the result of weight loss.

• 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.

• Journal of Ocean Engineering and Technology
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• v.22 no.6
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• pp.35-40
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• 2008

The effect of counterpart roughness on abrasive wear characteristics of side plate materials of FRP ship, which were composed of glass fiber and unsaturated polyester resin composites, were investigated at ambient temperature by pin-an-disc friction test. The friction coefficient, wear rate and cumulative wear volume of these materials against SiC abrasive paper were determined experimentally. The wear rate of these materials decreased rapidly with sliding distance and then maintained a constant value. It was increased as counterpart roughness was rougher in a wear test. The cumulative wear volume tended to increase nonlinearly with sliding distance and depended on applied load and sliding speed for these composites. It could be verified by SEM photograph of fracture surface that major failure mechanisms were overlapping layers, microcutting, deformation of resin, delamination, and cracking.

• Journal of Power System Engineering
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• v.14 no.4
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• pp.68-75
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• 2010

The effect of dispersion agent, the content and size of nanoparticle on the mechanical and thermal properties has been investigated in $TiO_2$ nanoparticle/epoxy resin composites(nanocomposites). The weight fraction of fabricated nanocomposites were 0, 1, 3, 5%, respectively. The glass transition temperature was lower than pure epoxy resin and decreased with the increasing of nanopaticle content. This is considered that the cross link of epoxy resin during solidification was hindered by the presence of nanoparticles. Nanocomposites of 3wt% content with dispersion agent showed the best tensile strength. The tensile strength of 20㎚ $TiO_2$ nanocomposites were higher than one of 200nm $TiO_2$ nanocomposites.

• Journal of the Korean Ceramic Society
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• v.37 no.2
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• pp.174-180
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• 2000

Y-TZP/mullite composites were prepared by the infiltration of Y-TZP precursor into partially reaction-sintered mullite. The addition of Y-TZP(~7.2 wt%) increased the bend strength(207 MPa), fracture toughness(4.6MPa.m1/2) and Vickers microhardness(853kg/$\textrm{mm}^2$) of the uninfiltrated mullite sintered at 162$0^{\circ}C$ for 10h by more than 75, 70 and 105%, respectively. Residual alumina-rich glass was observed at a mullite/mullite junction, due to the mullitization reaction of silica melt with crystalline $\alpha$-Al2O3 during a final sintering. Although ZrO2 inclusions improved the final sintered density of mullite they did not effectively prevent its grain growth.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.188-193
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• 2008

Epoxy/Organically Modified Layered Silicate Nanocomposites were prepared by dispersing synthetic layered silicate modified with alkyl ammonium ions. In the dispersing process, the organically modified layered silicate were mixed in epoxy resin with shearing, and aggregation of the silicate were removed by centrifugal separation after mixing epoxy resin and silicates. Micrographs taken by transmission electron microscopy(TEM) indicate that the nanocomposites have a mixed morphology including both parallel silicate layers and exfoliated silicate layers area, As the thermal properties, the glass transition temperature of the nanocomposites was shifted to a higher temperature($+6^{\circ}C$)than pure epoxy. Furthermore, dispersion of OMLS will prevented relative permittivity from increasing at a high temperature above the glass transition temperature.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.86-91
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• 2002

Glass/phenolic composite laminates have been used in the field of non-flammable light rail transit and their applications have expanded more widely. Low velocity impact tests have been used to evalute the effect of temperature and acceleration aging on low velocity impact response of phenolic matrix composites reinforced with woven E-glass fabric. The damage of matrix cracking and delamination are suddenly reduced the compressive strength after impact. The damage area increases with increasing temperature and impact energy. UT C-scan is used to determine damage areas by impact loading. Therefore, all this observations indicate reduced impact damage resistance and damage tolerance of the laminates at elevated temperature.

• Journal of Adhesion and Interface
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• v.2 no.4
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• pp.1-9
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• 2001

Silicone sealants are composed of polymer, plasticizer, crosslinker, catalyst and filler. Types and compositions of components are effected on sealant performances. In recent, use of alkoxy type silicone sealant increased due to environmental advantage. In this study, we investigated effects of component types and ratios on one-part room temperature curable alkoxy type silicone sealant preparation and adhesion properties. Alkoxy type silicone sealants were prepared with various PDMS (polydimethylsiloxane) viscosities. In addition, the effect of plasticizer, crosslinkers, and catalyst on sealant obtained from by mixture of PDMS viscosities of 20000 and 80000 was investigated. Reaction temperature on change of mixing time was observed, and then proper crosslinking systems were found. Adhesion (properties) of silicone sealants were measured. In the sealants preparation, stable reaction was achieved by adjusting composition variance ratio in the sealant mixture temperature below $40^{\circ}C$. The adhesion properties of sealant differ from substrate composition. The order of adhesion strength was glass/glass > glass/aluminum > aluminum/aluminum system. The elongation of sealant was increased as polymer viscosity and plasticizer content increased. The strength was increased as crosslinker and plasticizer decreased, while catalyst increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1671-1676
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• 2015

A unique crystallization behavior of poly(L-lactide)(PLLA)/poly(D-lactide)(PDLA) stereocomplex(SC) was observed when a PLLA/PDLA blend was subjected to the specific melting conditions. Therefore, we tried to blend PLLA and PDLA at overall composition to form PLA stereocomplexes. Moreover, impact modifier and reinforcement materials such as talc and glass fiber added to enhance the mechanical and thermal properties such as impact strength and heat distortion temperature(HDT). As a result, we got one representative result, one composite recipe with HDT $115^{\circ}C$. For more economic technology, we tried to blend PLLA and Polypropylene at overall composition and we got another representative result which could be applied to current PP/talc composites and ABS materials. The core technology of this might be the well dispersion of glass fibers into the matrix resin such as PP, PLLA and impact strength modifier.